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MARCH 2016

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THE DEADLIFT EDITIONBy Chris Beardsley

Welcome

Welcome to the Deadlift Edition! In this excitingedition we have covered two brand-new deadlift

biomechanics studies, one of which compared hex-bar

deadlifts and conventional straight-bar deadlifts, and

another which compared deadlifts with and without

chain resistance. Both of these are valuable additions

to the literature, but the hex-bar stud had the slight

edge for sheer interest value, as it both replicates

some of the findings of earlier studies, as well as

building upon them to provide new information.

What did we know about hex-bar deadlifts?

Introduction

ntil ver recentl, onl one stud had ever compared

the hex-bar and straight-bar deadlifts, at least as faras the biomechanics are concerned. "winton et al.

#$%&&' compared the hex-bar and conventional

straight-bar deadlifts in a group of powerlifters at a

range of loads, from &% ( )%* of &+. he did a lot

of hard wor in this investigation and measured a

great man variables. /owever, the did not record

the electromograph #E0' of an muscles, so it was

exciting to see that 1amara et al. #$%&2' recorded

E0 in their paper, as well replicating some of the

same data that was previousl measured b "winton

et al. #$%&&'. +eplication is often overlooed in the

literature, but it is actuall a reall important thing to

do in science, as it reduces the ris of tpe I error

when looing at the literature as a whole. In otherwords, if all the studies in the same area produce the

same outcome, we can be fairl sure that the effect is

real, and not caused b chance. 3f course, it does not

do awa with methodological problems, but that is a

stor for another time!

Maximal deadlift loads

3riginall, "winton et al. #$%&&' measured the &+ for

both the straight-bar and hex-bar deadlifts, in their

population of powerlifters. he found that the hex-

bar deadlift allowed a greater load to be used for the

&+ compared to the straight-bar deadlift #$24 5 6&

g vs. $64 5 78g'. he had hpothesi9ed that this

would happen, because of the smaller external

moment arms at the hip and nee in the hex-bar,

compared to the straight-bar. In contrast, in their

population of oung males with some resistance

training experience, and the abilit to deadlift at least

&.4 times bodweight, 1amara et al. #$%&2' did not

find an significant difference in &+ between the

straight-bar and hex-bar deadlifts #&)&.6 5 $:.7 vs.

&)&.& 5 $:.2g'. It was interesting to see that the

finding b "winton et al. #$%&&' was not replicated b

this stud, although we can see that the loads lifted

were much smaller. ;erhaps the difference lies in the

fact that the recreationall-trained sub<ects in this

stud were much less silled than the powerlifters

investigated previousl.

Joint angle movements

3ne of the uni=ue features of the hex-bar deadlift is

the fact that the lifter stands exactl in the middle of

the barbell center of mass, in the sagittal plane. his

means that <oint angle movements must differ when

picing up the barbell from the floor, in comparison

with a straight-bar deadlift, irrespective of whether the

conventional stle deadlift is used, or the sumo stle.In the stud performed b "winton et al. #$%&&', the

researchers used motion analsis to record <oint angle

movements. he found that the trun, hip and anle

angles at lift-off were not significantl different

between the hex-bar and straight-bar deadlifts,

although the did note that the nee angle was much

greater #more flexed' when using the hex-bar than

when using the straight-bar #:).) vs. :$.4 degrees'.

his greater amount of nee flexion maes the hex-

bar deadlift loo slightl more lie a sumo deadlift, or

even a s=uat, than the conventional straight-bar

deadlift. nfortunatel, 1amara et al. #$%&2' did not

record <oint angle movements in their stud.

External moment arm lengths

External moment arm lengths sound intimidating but

are actuall ver straightforward. When ou pic up

the barbell from the floor in the deadlift, our muscles

exert forces on our <oints to create a sstem of net

<oint moments that wor together to move the bar

verticall upwards. B >ewton?s @aws, these net <oint

moments must be e=ual and opposite to the moments

exerted in the opposite direction b the barbell. As we

all now, moments are calculated b multipling force

b the moment arm length. he force here is the sum

of the barbell weight and its inertia #determined b

how fast ou accelerate the bar'. he moment arm

lengths are determined b the distances between the

barbell center of mass #in the sagittal plane' and the

<oint centers. When the external moment arm lengths

are long, this means that net <oint moments #and

therefore muscle forces' must be ver large in order

to counteract them. In their stud, "winton et al.

#$%&&' measured the external moment arm lengths at

each ma<or lower-bod <oint #lumbar @4-"&C, hip,

nee and anle'. he found that the lumbar, hip and

anle moment arm lengths were not significantl

different between the hex-bar and straight-bar

deadlifts, but the nee moment arm length differed

greatl, changing from ).6cm in the straight-bar

deadlift to -&.8cm in the hex-bar deadlift. his

surprising difference has two implications. irstl, it

means that the external moment arm length at thenee was actuall smaller in the hex-bar deadlift than

in the conventional deadlift. While this sounds illogical,

it is the second implication that clarifies the situation.

he change from a positive value #in the straight-bar

deadlift' to a negative value #in the hex-bar deadlift'

means that the net <oint moment re=uired in the

conventional, straight-bar deadlift to counteract the

external moment produced b the barbell is a nee

flexion moment, which is produced b the hamstrings,

while in the hex-bar deadlift it is a nee extension

moment, which is produced b the =uadriceps!

1opright "trength and 1onditioning +esearch @imited, $%&2

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Net joint moments

ollowing up on their analsis of external moment arm

lengths, "winton et al. #$%&&' used inverse dnamics

to calculate net <oint moments. After doing this

analsis, the actuall found more significant results

than when <ust looing at the external moment arm

lengths alone. he found that there were lower pea

moments at the lumbar spine, at the hip and at theanle in the hex-bar deadlift compared to the straight-

bar deadlift, but an increased pea moment at the

nee. his expands on the moment arm length

findings =uite a lot, and tells us that the hex-bar

deadlift cuts down on the low bac extensor, hip

extensor, and anle plantar-flexor contributions to the

lift, compared with the straight-bar deadlift. It also

confirms that the net <oint moment at the nee is for

nee extension, which is generated b the =uadriceps,

while in the conventional deadlift it is for nee flexion,

which is produced b the hamstrings. #It is worth

noting here that because of co-contraction, both

muscle groups will be contracting hard, but the

observations made here still indicate that there is adifference in terms of which muscle group is exerting

the most force in each deadlift variation.' ltimatel,

these findings put the hex-bar deadlift closer to the

sumo deadlift or the s=uat than the conventional

straight-bar deadlift. 3r to put it another wa, the

conventional straight-bar deadlift is a more hip-

dominant lift than the hex-bar deadlift.

Peak force, peak velocity, and peak power

When "winton et al. #$%&&' performed their original

investigation, the found that the hex-bar deadlift

produced greater pea force, pea velocit and pea

power outputs compared to the conventional straight-

bar deadlift. And <ust lie "winton et al. #$%&&',

1amara et al. #$%&2' also found that the hex-bar

deadlift displaed significantl greater pea force,

pea power, and pea velocit compared to the

straight-bar deadlift. /owever, this is not simple

replication, as there is more to sa. hese differences

were achieved in both studies even though the &+

values were different in terms of absolute load in in

"winton et al. #$%&&' but the same in 1amara et al.

#$%&2', suggesting that it was not the greater load in

"winton et al. #$%&&' that was primaril responsible

for the differences in force and power output between

the straight-bar and hex-bar deadlifts. Exactl wh the

hex-bar is superior in these respects is something of a

pu99le, but might be because the overall worload is

more evenl apportioned across all <oints, meaningthat there is no one <oint #lie the hips in the straight-

bar deadlift' that is the limiting factor and therefore

woring maximall to produce ver high forces #and

therefore contracting slowl, in accordance with the

force-velocit relationship'. Indeed, we can see that in

1amara et al. #$%&2', although the difference in pea

force was significant, it was not that big. In contrast,

the differences between lifts in respect of pea power

and pea velocit were much bigger. his fits with the

idea that the hex-bar allows the lower bod muscles

to wor in a more co-ordinated wa and share the

load, thereb woring closer to the velocit-end of the

force-velocit spectrum.

Electromyography EM!"

Although "winton et al. #$%&&' did not record E0 in

their stud, 1amara et al. #$%&2' did. It is important

to note that the also used a ver sound approach to

taing their measurements, as the sub<ects lifted the

straight-bar deadlift #in a conventional stle' and the

hex-bar deadlift for 7 repetitions each with 24* and

)4* of &+ on separate occasions. he same relativeload was used for each exercise variation, and onl

sub-maximal numbers of repetitions were performed

#i.e. not to muscular failure'. hese two features are

critical for us to be confident that the E0 data can be

compared between the two exercises #and are usuall

the reasons wh other E0 studies are not as useful,

such as those comparing high- and low-loads taen to

failure'. As expected based on the net <oint moments

analsis performed b "winton et al. #$%&&', 1amara

et al. #$%&2' reported significantl greater E0

amplitudes in the vastus lateralis #=uadriceps' for the

hex-bar deadlift compared to the straight-bar deadlift,

and the straight-bar deadlift displaed significantl

greater E0 amplitudes in the biceps femoris and theerector spinae, compared to the hex-bar deadlift. his

is exactl in line with the net <oint moment data

reported b "winton et al. #$%&&', which found lower

lumbar extensor and lower hip extensor net <oint

moments in the hex-bar deadlift, and is consistent

with the idea that the conventional straight-bar

deadlift is a more hip-dominant exercise than the hex-

bar deadlift.

Conclusions

3verall, lie the researchers who performed these

studies, we can conclude that the hex-bar deadlift

involves a much less hip-dominant pattern of muscle

activation than the straight-bar deadlift, and a morenee-dominant pattern. Although not measured, it

also liel involves lower <oint loads at the lumbar

spine, which ma be advantageous for training more

fre=uentl and avoiding overload. And perhaps most

importantl of all, it seems that the hex-bar deadlift

involves greater pea force, power, and velocit,

whether the absolute loads for the &+ are similar or

greater. his ma mae the hex-bar deadlift the best

option for training athletes, who need to develop the

abilit to produce large amounts of force at ver high

speeds.


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Strength coach notes

Effect of strength and power

training on tackling a#ility in

semiprofessional rug#y league

players

he researchers concluded that rugb league plaers who displaed

the greatest improvements in absolute and relative s=uat strength

displaed the largest changes in tacling abilit. he improvements in

lower-bod strength were closel associated with the beneficial

changes in tacling abilit.

Efficacy of a four$week uphill

sprint training intervention in

field hockey players

he researchers concluded that following <ust ) sessions of uphill

running /II, repeated sprint performance was improved b &$ ( &4*

in semi-professional female field hoce plaers, and this was also

accompanied b beneficial changes in certain specific hoce fitness

tests.

%trength training using elastic

#and improves muscle power and

throwing performance in young

female hand#all players

he researchers concluded that a 2-wee program of elastic resistance

band shoulder internal rotation training improved shoulder internal

rotation power output and ball throwing speed in oung, female

handball athletes.

%elective effects of training

against weight and inertia on

muscle mechanical properties

he researchers concluded that although training using different tpes

of external load #weight, weight plus inertia, or inertia onl' can all

enhance maximal power output to a similar extent, the achieve this

goal b different gains in maximal force or maximal velocit. +emoval

of the inertial component of the resistance #as is often done b using

machine-based variable resistance' might be more effective for

enhancing maximum force, while removal of the weight component

#as is often done b using ballistic movements with light loads' might

be most effective for enhancing maximal velocit.

&ilateral practice improvesdominant leg performance in

long jump

he researchers concluded that long <umping practice with both thedominant and non-dominant legs was superior to long <umping

practice with onl the dominant leg over a &$-wee period. his ma

be because training with both legs involves the presence of a cross-

over effect produced through as et unclear central adaptations.

'he effects of frontal$ and

sagittal$plane plyometrics on

change$of$direction speed and

power in adolescent female

#asket#all players

he researchers concluded that both frontal plane and sagittal plane

plometrics are effective for improving vertical, hori9ontal, and lateral

<umping performance, as well as change-of-direction abilit. /owever,

the also concluded that frontal plane plometrics are more effective

for lateral <umps and change-of-direction abilit, while sagittal plane

plometrics are more effective for improving vertical <umping.

(n examination of muscle

activation and power

characteristics while performing

the deadlift exercise with straight

and hexagonal #ar#ells

he researchers concluded that using the hexagonal and straight

barbell deadlifts leads to different patterns of muscle activation, and

that the hexagonal barbell ma be more effective at developing

maximal force, power, and velocit, despite similar &+ values.


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Sports medicine notes

Neck muscular strength,

training, performance and sport

injury risk) a review

he researcher concluded that there are differences in nec strength

between athletes, which seem to be partl caused b differences in

nec muscle mass, that specific strength training programs generall

produce increases in nec strength, and that isometric nec strength

and training are related to nec in<ur and concussion ris in sport.

%tretching of active muscle

elicits chronic changes in

multiple strain risk factors

he researchers concluded that active stretching #or eccentric training'

produces substantial gains in <oint +3, which are liel greater than

those produced b passive stretching. he also concluded that active

stretching produced changes in muscle-tendon parameters that ma

reduce in<ur ris, including reducing muscle stiffness, increasing

muscle strength, increasing energ storage, and increasing +3.

*ip muscle strength predicts

non$contact anterior cruciate

ligament injury in male and

female athletes a prospective

study

he researchers concluded that there are significant relationships

between baseline hip external rotation and hip abduction strength, and

future non-contact A1@ in<ur. +educed hip external rotation and hip

abduction strength led to increased in<ur ris, in both males and

females.

'he vertical drop jump is a poor

screening test for (+ injuries in

female elite soccer and hand#all

players a prospective cohort

study of -./ athletes

he researchers concluded that there are ver limited grounds for using

inetic or inematic parameters measured during the drop landing and

subse=uent maximal <ump for the screening of A1@ in<ur ris.

*ip joint pathology) relationship

#etween patient history,

physical tests, and arthroscopyfindings in clinical practice

he researchers concluded that combining patient histor and phsical

tests leads to a higher diagnostic accurac for either AI andFor hip

labral patholog compared to an one individual test alone.

(n anatomic investigation of the

0#er test

he researchers concluded that these findings refute the hpothesis

that the IB limits hip adduction during either the 3 or 3, and

thereb =uestion the validit of either test as a measurement of IB

tightness. +ather the tests appear to measure the tightness of the

gluteus medius and minimus muscles as well as the hip <oint capsule.

Mirror training augments the

cross$education of strength and

affects inhi#itory paths

he researchers concluded that viewing the exercising limb in a mirror

increases the magnitude of the cross-education effect, which seems to

be produced b greater changes in intracortical inhibition. his finding

ma have applications during rehabilitation.

.1 days of #ed rest induces a

decline in satellite cell content

and ro#ust atrophy of skeletal

muscle fi#ers in middle$aged

adults

he researchers concluded that there are rapid and adverse changes in

muscle fiber properties as a result of bed rest lasting &6 das, including

losses in lean bod mass, reductions in /1 percentage, and large

decreases in mean fiber cross-sectional area and satellite cell content,

as well as small reductions in monuclear content.


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HOW TO READ THIS JOURNAL

After the contents page, ou will find a total of 4%

stud reviews. Initiall, this might feel a bit daunting,

but ou need onl read the ones that are most

relevant to ou. It would be unusual for ever stud in

an edition to be important for everone! When ou

turn to each one of the stud reviews, it will loo

something lie thisG

Study title ( date ) ← here, we detail the stud that

we are reviewing, and we provide ou with a hperlin

#in the date' to either ;ubed or the <ournal, in case

ou want to grab the full text for ourself.

Background ← here, we give ou as much of the

bacground to the stud as we can, based on what

research has been done before.

OBJC!"#$ ← here, we tell ou what the goals of

doing the stud were, and we also note the exact

measurements that were taen in support of each

goal. It is vital that we tell ou what the measurement

methods were, as some are more reliable than others.

%O%&'(!"O)$ ← here, we note who the sub<ects in

the stud were. his can be important, if we thin thatdifferent tpes of sub<ect #untrained vs. trained, or old

vs. oung, or male vs. female' might respond

differentl to the intervention.

")!*#)!"O)$ ← here, we explain either the tpe

of exercise, the tpe of worout or the tpe of training

that the sub<ects did while the researchers too their

measurements.

What happened? ← here, we explain what the

researchers found. 3ften, we will write the term

Hsignificant in this section. When researchers sa a

result is Hsignificant, the don?t mean it is important,

or meaningful. What the mean is that the result was

unliel to have occurred because of chance.

What did the researchers conclude? ← here, we

report what the researchers concluded. "ometimes,

researchers get a bit excited and conclude a little bit

more than their stud allows them to, and we either

remove this where it happens, or we explain wh the

ma have been a bit over-enthusiastic.

'imitations ← here, we explain which parts of the

investigation were wea, or which aspects of it might

prevent us from extrapolating the findings.


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Strength and Cnd!"n!ng Re#ear$h

CONTENTS

THE DEADLIFT EDITION%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%2

HOW TO READ THIS JOURNAL%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%6

CONTENTS%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%&

1% STREN'TH ( CONDITIONIN') POWER AND H*PERTROPH*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%10

1. Efect o strength and power training on tackling ability in semiproessional rugby league players, by Speranza, Gabbe, ohnston !

Sheppard, in "he ournal o Strength ! #ondi$oning %esearch &'(1)*.......................................................................................................11

'. E+cacy o a ourweek uphill sprint training inter-en$on in eld hockey players, by akeman, /c/ullan, ! 0abra, in "he ournal o

Strength and #ondi$oning %esearch &'(12*.................. ..................................... ...................................... ...................................... ............. 1'

3. Strength training using elas$c band impro-es muscle power and throwing perormance in young emale handball players, by /ascarin,

4e 5ira, 6ancini, 4e #astro, 4a Sil-a, ! 7ndrade, in ournal o Sport %ehabilita$on &'(12* .................................. ..................................... 13

8. 9eterogeneity in resistance traininginduced muscle strength and mass responses in men and women o diferent ages, by 7h$ainen,

:alker, ;eltonen, 9ol-iala, Sillanp<<, =ara-irta, ! 9ulmi, in 7ge &'(12*....... ...................................... ...................................... ................ 18

). Gene$c -ariability among power athletes> "he stronger -s. the aster, by 0en?aken, Eliakim, @emet, ! /eckel, in "he ournal o

Strength ! #ondi$oning %esearch &'(12*....................................................................................................................................................1)

2. AnBuence o diferent speeds o muscle ac$ons in the maCimum dynamic strength, in the maCimum -olume o repe$$ons, and rated

percei-ed eCer$on, by Souza, #ampos, /oreira, Guimar aes, Sil-a, ! Sil-a, in ournal o ECercise ;hysiology Dnline &'(12* ....... ...... ......12

. Selec$-e efects o training against weight and iner$a on muscle mechanical proper$es, by 4uric, #uk, Srecko-ic, /irko-, @edelko-ic,

! aric, in the Anterna$onal ournal o Sports ;hysiology and ;erormance &'(12*....................................................................................1

F. "he efects o rontal and sagialplane plyometrics on changeodirec$on speed and power in adolescent emale basketball players,

by /c#ormick, 9annon, @ewton, Shultz, 4etling ! oung, in Anterna$onal ournal o Sports ;hysiology and ;erormance &'(12* ....... ..1F

H. Efect o superimposed electromyos$mula$on on back eCtensor strengthening> a pilot study, by ;ark, Seo, ! 5ee, in "he ournal o

Strength ! #ondi$oning %esearch &'(12*....................................................................................................................................................1H

1(. "he efect o highintensity inter-al cycling sprints subseIuent to armcurl eCercise on muscle strength and hypertrophy in untrained

men> a pilot study, by =ikuchi, oshida ! @akazato, in "he ournal o Strength ! #ondi$oning %esearch &'(1)*........ ............................. '(

11. 0ilateral prac$ce impro-es dominant leg perormance in long ump, by Jocke, Spancken, Stockinger, "hKrer, ! Stein, in European

ournal o Sport Science &'(12*..................................................... ...................................... ..................................... .................................... '1

1'. "he importance o muscular strength in athle$c perormance, by Suchomel, @imphius, ! Stone, in Sports /edicine &'(12* .................. ''

13. #entral and peripheral a$gue during resistance eCercise L a cri$cal re-iew, by ?aMc, #halimoniuk, /aszczyk, GoNaO, ! 5angort, in

ournal o 9uman =ine$cs &'(12*..................................................... ..................................... ...................................... ................................ '3

18. @on‐local muscle a$gue> efects and possible mechanisms, by 9alperin, #hapman, ! 0ehm, in European ournal o 7pplied ;hysiology

&'(1)*.......................................... ...................................... ...................................... ..................................... ...................................... .......... '8

2% +IOMECHANICS AND MOTOR CONTROL%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%2,

1). 7n eCamina$on o muscle ac$-a$on and power characteris$cs while perorming the deadliP eCercise with straight and heCagonal

barbells, by #amara, #oburn, 4unnick, 0rown, Galpin, ! #osta, in "he ournal o Strength ! #ondi$oning %esearch &'(12* ....... ....... ....'2

12. 7n electromyographic and orce plate analysis o the deadliP perormed with and without chains, by @iem, #oburn, 0rown, 5ynn, !

#iccone, in "he ournal o Strength ! #ondi$oning %esearch &'(12*..........................................................................................................' 1. Anterac$on between leg muscle perormance and sprint accelera$on kinema$cs, by 5ockie, alil-and #allaghan, efriess, ! /urphy, in

ournal o 9uman =ine$cs &'(1)*..................................................... ..................................... ...................................... ................................ 'F

1F. 7nkle posi$on during the @ordic curl does not afect muscle ac$-ity o the biceps emoris and medial gastrocnemius, by #omort,

%egan, 9errington, "homas, /c/ahon ! ones, in ournal o Sport %ehabilita$on &'(12*.......................................................................'H

1H. #ontribu$on o elas$c $ssues to the mechanics and energe$cs o muscle unc$on during mo-ement, by %oberts, in ournal o

ECperimental 0iology &'(12*............................ ..................................... ...................................... ..................................... ............................ 3(

'(. "he increase in noncrossbridge orces aPer stretch o ac$-ated striated muscle is related to $$n isoorms, by #ornachione, 5eite,

0agni, ! %assier, in 7merican ournal o ;hysiology &'(12*........................................................................................................................31

'1. Eccentric contrac$on L unra-eling mechanisms o orce enhancement and energy conser-a$on, by @ishikawa, in "he ournal o

ECperimental 0iology &'(12*............................ ..................................... ...................................... ..................................... ............................ 3'

''. @eural control o lengthening contrac$ons, by 4uchateau ! Enoka, in "he ournal o ECperimental 0iology &'(12* ...... ....... ....... ....... ....33


8/18/2019 Scr Mar 2016 PDF



'3. /uscle orce loss and soreness subseIuent to maCimal eccentric contrac$ons depend on the amount o ascicle strain in -i-o, by

Guilhem, 4oguet, 9auraiC, 5acourpaille, ubeau, @ordez ! 4orel, in 7cta ;hysiologica &'(12*.................................................................38

'8. 7rchitectural adapta$ons o muscle to training and inury L a narra$-e re-iew outlining the contribu$ons by ascicle length, penna$on

angle and muscle thickness, by "immins, Shield, :illiams, 5orenzen, ! Dpar, in 0ri$sh ournal o Sports /edicine &'(12* .....................3)

'). Efect o neck BeCion restric$on on sternocleidomastoid and abdominal muscle ac$-ity during curlup eCercises, by 5ee, /oon, !

9ong, in ournal o ;hysical "herapy Science &'(12*.............. ...................................... ..................................... ...................................... .... 32

'2. Electromyographic ac$-ity and 1)%/ load during resistance eCercises on stable and unstable suraces, by 7randa, /ancini, :erneck,@o-aes, 4a Sil-aGrigoleo, ! 6ianna, in ournal o ECercise ;hysiology Dnline &'(12* .................................... ..................................... ... 3

-% ANATOM*) PH*SIOLO'*) AND NUTRITION%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%% -.

'. "he efects o a high protein diet on indices o health and body composi$on L a crosso-er trial in resistancetrained men, by 7ntonio,

Ellerbroek, Sil-er, 6argas, ! ;eacock, in ournal o the Anterna$onal Society o Sports @utri$on &'(12*.................................... ...............3H

'F. 9igher compared with lower dietary protein during an energy decit combined with intense eCercise promotes greater lean mass gain

and at mass loss a randomized trial, by 5ongland, Dikawa, /itchell, 4e-ries, ! ;hillips, in "he 7merican ournal o #linical @utri$on

&'(12*.......................................... ...................................... ...................................... ..................................... ...................................... .......... 8(

'H. ;rotein QreIuirementsR beyond the %47> implica$ons or op$mizing health, by ;hillips, #he-alier, ! 5eidy, in 7pplied ;hysiology,

@utri$on, and /etabolism &'(12*.............................. ..................................... ...................................... ...................................... ................ 81

3(. #Dinhibitor inBuence on skeletal muscle ber size and metabolic adapta$ons to resistance eCercise in older adults, by "rappe,

%atchord, 0rower, 5iu, 5a-in, #arroll, ! "rappe, in "he ournals o Gerontology Series 7 &'(12* ..................................... ......................... 8'

31. Ea$ng reIuency, ood intake, and weight> systema$c re-iew o human and animal eCperimental studies, by %aynor, Gof, ;oole, !#hen, in Jron$ers in @utri$on &'(1)*...........................................................................................................................................................83

3'. 0ody composi$on and energy intake T skeletal muscle mass is the strongest predictor o ood intake in obese adolescents> the 9E7%"

"rial, by #ameron, Sigal, =enny, 7lberga, ;rudU9omme, ;hillips, ! Goldeld, in 7pplied ;hysiology, @utri$on, and /etabolism &'(12* . 88

33. 5ow energy a-ailability in eCercising men is associated with reduced lep$n and insulin but not with changes in other metabolic

hormones, by =oehler, 9oerner, Gibbs, ?inner, 0raun, 4e Souza, ! Schaenzer, in ournal o Sports Sciences &'(12* ................................. 8)

38. /uscle memory and a new cellular model or muscle atrophy and hypertrophy, by Gundersen, in "he ournal o ECperimental 0iology

&'(12*.......................................... ...................................... ...................................... ..................................... ...................................... .......... 82

3). 7 newly disco-ered muscle L the tensor o the -astus intermedius, by Grob, 7ckland, =uster, /anestar, ! Jilgueira, in #linical 7natomy

&'(12*.......................................... ...................................... ...................................... ..................................... ...................................... .......... 8

/% PH*SICAL THERAP* AND REHA+ILITATION%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%% %%% /.

32. "he rela$onship between training load and inury, illness and soreness> a systema$c and literature re-iew, by 4rew ! Jinch, in Sports/edicine &'(12*............................... ...................................... ..................................... ...................................... ...................................... ..... 8H

3. @eck muscular strength, training, perormance and sport inury risk> a re-iew, by 9rysomallis, in Sports /edicine &'(12* ..................... )(

3F. 7 comparison o two stretching programs or hamstring muscles> a randomized controlled assessorblinded study, by 4emoulin, :ols,

#he-alier, Granado, Grosdent, 4epas, ! 6anderthommen, in ;hysiotherapy "heory and ;rac$ce &'(12*.................. .............................. )1

3H. #omparison o efects o sta$c, propriocep$-e neuromuscular acilita$on and /ulligan stretching on hip BeCion range o mo$on> a

randomized controlled trial, by VldVrVm, Dzyurek, "osun, Wzer, ! Gelecek, in 0iology o Sport &'(12* ................................. ...................... )'

8(. Stretching o ac$-e muscle elicits chronic changes in mul$ple strain risk actors, by =ay, %ichmond, "albot, /ina, 0aross, ! 0laze-ich, in

/edicine ! Science in Sports ! ECercise &'(12*........... ..................................... ...................................... ..................................... ............... )3

81. 18 days o bed rest induces a decline in satellite cell content and robust atrophy o skeletal muscle bers in middleaged adults, by

7rentson5antz, English, ;addonones ! Jry, in ournal o 7pplied ;hysiology &'(12* ................................. ...................................... .......)8

8'. /irror training augments the crosseduca$on o strength and afects inhibitory paths, by ?ult, Goodall, "homas, Solnik, 9ortobXgyi, !

9owatson, in /edicine ! Science in Sports ! ECercise &'(12*....................................... ..................................... ...................................... .. ))

83. /%A analyses show that =inesiotaping afects much more than ust the targeted supercial $ssues and causes heterogeneous

deorma$ons within the whole limb, by ;amuk ! ucesoy, in ournal o 0iomechanics &'(1)*.................................................................)2

88. "he role o descending modula$on in manual therapy and its analgesic implica$ons L a narra$-e re-iew, by 6igotsky ! 0ruhns, in ;ain

%esearch and "reatment &'(1)*...................................................................................................................................................................)

8). 9ip muscle strength predicts noncontact anterior cruciate ligament inury in male and emale athletes a prospec$-e study, by

=hayambashi, Ghoddosi, Straub, ! ;owers, in "he 7merican ournal o Sports /edicine &'(1)*.... ...................................... ....................)F

82. "he -er$cal drop ump is a poor screening test or 7#5 inuries in emale elite soccer and handball players a prospec$-e cohort study o

1( athletes, by =rosshaug, Stefen, =ris$anslund, @ilstad, /ok, /yklebust, ! 0ahr, in "he 7merican ournal o Sports /edicine &'(12*

......................................................................................................................................................................................................................)H

8. 9ip oint pathology> rela$onship between pa$ent history, physical tests, and arthroscopy ndings in clinical prac$ce, by "issen, #ingel,

6isser, 9Ylmich, ! @ihuis‐-an der Sanden, in Scandina-ian ournal o /edicine ! Science in Sports &'(12* ................................... ........2(

8F. H)Z pre-alence o abnormality on hip /%A in elite academy le-el rugby union[ a clinical and imaging study o hip disorders, by Jarrell,

/cGrath, 9ogan, 5ogan, 4en-ir, DR#onnell, ! :ilson, in ournal o Science and /edicine in Sport &'(12* .................................... .......... 21


8/18/2019 Scr Mar 2016 PDF



8H. 7n anatomic in-es$ga$on o the Dber test, by :ille, =eim, Shostrom, ! 5omneth, in "he 7merican ournal o Sports /edicine &'(12*

......................................................................................................................................................................................................................2'

)(. 7ngry posture, by %osario, 4iogenes, /aei, ! 5eite, in ournal o 0odywork ! /o-ement "herapies &'(12*.................................... .... 23


8/18/2019 Scr Mar 2016 PDF



1% STREN'TH ( CONDITIONIN') POWER AND

H*PERTROPH*


8/18/2019 Scr Mar 2016 PDF



Effect of strength and power training on tackling

a#ility in semiprofessional rug#y league players, #y

%peran2a, !a##ett, Johnston 3 %heppard, in 'he

Journal of %trength 3 +onditioning 4esearch 5/.6 "

Background

+ugb is a contact team sport belonging to thefootball codes, which include Australian +ules football,

American football and 0aelic football. here are two

main tpes of rugbG rugb league and rugb union.

@ie all of the football codes, rugb league is a game

of two halves involving intermittent activit for the

plaers, in which periods of slow waling, <ogging or

standing are interspersed with periods of high-speed

running or sprinting. In rugb league, the duration of

each half is 6% minutes. ;laers are formall divided

into two main groups #forwards and bacs', although

some analsts have identified a third group, nown as

ad<ustables, who perform a varied role. here are &7

plaers in rugb league, comprising : bacs #& full

bac, $ wingers, $ centers, & five-eighth and & half-

bac' and 2 forwards #$ props, & hooer, $ second-

row, and & loc'. "coring in rugb league is achieved

in an of four wasG tries and conversions, penalt

goals and drop goals. 1urrentl, the rules specif that

a tr is worth 6 points, a conversion is worth $ points,

a penalt is worth $ points, and a drop-goal is worth &

point. he two main full professional leagues for

rugb league are the Australasian >ational +ugb

@eague #>+@' and the European "uper @eague #E"@',

although there are a number of other domestic

championships in which the game is plaed to a high

level. +ugb union is ver similar to rugb league and

is also plaed in two halves of 6% minutes but the line-

up of plaers differs in that there are &4 plaers,

comprising ) forwards and : bacs. he forwards

comprise $ props, & hooer, $ second-row forwards

#confusingl called locs', and 7 bac-row forwards

#blind-side and open-side flaners on either side and

the number ) in the middle'. he bacs comprise the

scrum-half, fl-half, inside centre, outside centre, right

wing, left wing and full bac. he scoring sstem

differs slightl from rugb league in that a tr is worth

4 points #& more than in rugb league', a conversion

is worth $ points #the same as in rugb league', a

penalt ic is worth 7 points #& more than in rugb

league' and a drop goal is also worth 7 points #$ more

than in rugb league'. In order to train rugb athletes

to achieve their full potential during games, it is

necessar to understand the demands of the gamever accuratel. Jideo analsis and 0lobal ;ositioning

"stem #0;"' analsis of plaer movements are a

new but increasingl common wa of anal9ing the

demands of the game, particularl as the allow for an

understanding of the lengths and speeds of running

activities. "uch analsis has in the past revealed the

ver short nature of the ma<orit of sprints in rugb

<ust as in man of the other football codes. an

coaches have therefore made use of a variet of

training methods to improve the sprint running abilit

of their rugb athletes.

OBJC!"#$ o explore the effects of a strength and

power training program on changes in upper-bod

strength #as measured b 7+ bench press', lower-

bod strength #as measured b 7+ s=uat', upper-

bod power #as measured b power output during the

plometric push-up recorded b a force platform', and

lower-bod power #as measured b countermovement

<ump #1K' power output recorded on a forceplatform', and to identif the associations between

these effects and changes in tacling abilit #as

assessed b video analsis of a standardi9ed one-on-

one tacling drill mared out of 2 points' in rugb

league plaers.

%O%&'(!"O)$ $6 semi-professional rugb league

plaers, aged $7.6 5 7.& ears.

")!*#)!"O)$ All sub<ects too part in an )-wee

strength and power training program as part of their

preseason training, performing 7 training sessions per

wee using 7 sets of 7 ( 2 repetitions for a range of

compound barbell movements, including bench press,

row, s=uat, lunge, and clean.

What happened?

Effects on muscular strength and power

he researchers identified significant improvements in

7+ s=uat, 7+ bench press, 1K power output, and

plometric push-up power output. he effect si9es

were all small except for the change in 7+ bench

press, which was trivial.

Effects on tackling a#ility and associations

he researchers identified a significant improvement

in tacling abilit as a result of the program, which

was small in effect si9e. he found that the change in

7+ s=uat was a moderatel-good predictor of thechange in tacling abilit #r L %.2%', as was the

change in 7+ s=uat relative to bod mass #r L %.46'.

In addition, when identifing responders and non-

responders to the training program, the researchers

found that the plaers with the greatest changes in

the 7+ s=uat and 7+ relative to bodweight both

displaed significantl greater changes in tacling

abilit than the non-responders, with a large effect

si9e.

What did the researchers conclude?

he researchers concluded that rugb league plaers

who displaed the greatest improvements in absolute

and relative s=uat strength displaed the largestchanges in tacling abilit. he improvements in

lower-bod strength were closel associated with the

beneficial changes in tacling abilit.

'imitations

he stud was limited in that there was no control

group, and it was unclear to what extent the other

training performed b the plaers might have affected

the outcomes observed.


http://www.ncbi.nlm.nih.gov/pubmed/26263118


8/18/2019 Scr Mar 2016 PDF


Efficacy of a four$week uphill sprint training

intervention in field hockey players, #y Jakeman,

McMullan, 3 &a#raj, in 'he Journal of %trength and

+onditioning 4esearch 5/.7"

Background

Interval training was first developed b trac and fieldathletes in the middle of the last centur to help

improve middle- and long-distance running

performance. rac running performance, lie

performance in other endurance sports, is dependent

upon three main phsiological factorsG aerobic

capacit, lactate threshold, and wor econom.

ogether, these variables can explain the large

ma<orit of the difference in endurance performance

between individuals in both heterogenous #varied' and

homogenous #similar' groups. In contrast, each of the

variables alone is onl able to explain the ma<orit of

the difference in endurance performance between the

individuals in heterogenous groups. Aerobic capacit is

measured using J3$-max, which is the volume of

oxgen that the bod can tae in and use effectivel in

a given period of time, usuall measured relative to

bodweight as mlFgFmin. @actate threshold is

measured b reference to blood lactate. During an

incremental exercise test, blood lactate initiall

remains close to its resting value. At a certain exercise

intensit, however, it rises above the resting value and

this exercise intensit is called the lactate threshold.

+unning econom #strictl wor econom if including

other exercise modalities' is a measurement of the

efficienc of the athlete. Econom is most commonl

described in terms of how much oxgen it taes to run

a given distance at a given speed. raditionall, the

exclusive method for developing endurance

performance was stead-state exercise. Indeed,

researchers have found that stead-state exercise can

improve endurance performance in untrained

individuals. /owever, improvements in alread well-

trained individuals are small. 1onse=uentl, studies

exploring the effects of stead-state exercise in

trained sub<ects have often failed to find significant

increases in endurance performance or in an of the

underling phsiological factors #aerobic capacit,

lactate threshold, and wor econom'. ore recentl,

high-intensit interval training #/II' has been

developed as a tool for increasing endurance

performance. /II can be broadl defined as repeated

bouts of short-to-moderate duration exercise #i.e. &%

seconds to 4 minutes' at an intensit greater than theanaerobic threshold. hese exercise bouts are divided

b short bouts of either low-intensit wor or

inactivit that allow either a partial or a full recover.

+esearchers have found that /II can improve

endurance performance in untrained individuals. he

increases are often larger than those following from

stead-state interventions of similar duration.

oreover, research has often found significant

increases in endurance performance in trained

individuals following /II exercise interventions.

OBJC!"#$ o assess the effects of a long-term

program of uphill running /II program on field

hoce performance #as measured b a shuttle sprint

dribble test #"D', both with and without a ball, and a

slalom "D, again both with and without a ball' and on

repeated sprint abilit #as measured b 2 sprints over

$$.8m with 7% seconds of rest between sprints'.

%O%&'(!"O)$ &6 semi-professional female field

hoce plaers, aged &) ( $2 ears, randoml

allocated into a control group #: sub<ects, 13>' or an

/II group #: sub<ects, /II', with the 13> group

maintaining their normal fitness training routine, and

the /II group replacing the $ non-hoce fitness

training sessions with $ /II sessions.

")!*#)!"O)$ he /II group performed 7%m

sprints outdoors on a vertical incline with an )*

gradient, with a &-minute recover period after each

sprint #including waling time'. Both sessions each

wee were identical. "ub<ects performed 2 sprints in

wee &, ) sprints in wee $, &% sprints in wee 7, and

&$ sprints in wee 6.

What happened?

Effects on hockey performance tests

he researchers found that onl some of the hoce

performance tests were significantl improved in /II

compared with 13> #"D without ball $.&* vs.

-$.)*M "D with ball %.:* vs. -7.)*' but others

were not #slalom "D with or without ball'.

Effects on repeated sprint test

he researchers identified a significant improvement

in repeated sprint test performance in the /II group

for total sprint time #&4.$* reduction', fastest single

sprint time #&$.&* decrease', the slowest singlesprint time #&6.2* reduction', and mean sprint time

#&4.2* decrease'. here were no significant changes

in repeated sprint test performance in the 13> group.


he researchers concluded that following <ust )

sessions of uphill running /II, repeated sprint

performance was improved b &$ ( &4* in semi-

professional female field hoce plaers, and this was

also accompanied b beneficial changes in certain

specific hoce fitness tests.

'imitations

he stud was limited as it onl tested one training

method, and did not compare this training method

with another, such as flat overground sprinting or

repeated sprinting.


8/18/2019 Scr Mar 2016 PDF


%trength training using elastic #and improves muscle

power and throwing performance in young female

hand#all players, #y Mascarin, 8e ira, 9ancini, 8e

+astro, 8a %ilva, 3 (ndrade, in Journal of %port

4eha#ilitation 5/.7 "

BackgroundElastic resistance training using elastic resistance

bands #E+Bs' is commonl-used in rehabilitation.

E+Bs resist being lengthened and exert a tensile force

directed towards returning to their resting length.

ensile force at an length depends upon the elastic

properties. Elastic properties are described b a

stress-strain relationship, where stress is the tensile

force per unit area and strain is the ratio of total

increase in length to starting length. he stress-strain

relationship provides a measure of the amount of

tensile force re=uired to increase the length of the

band b a given distance. he slope of the stress-

strain relationship is the elastic modulus. "tress is

plotted on the -axis and strain on the x-axis, so a

larger elastic modulus implies a steeper gradient

wherein larger tensile forces are re=uired for the same

increases in E+B length. hus, stiffer E+Bs have a

higher elastic modulus while less-stiff E+Bs have a

lower elastic modulus. "o using a stiffer E+B maes an

exercise harder. Also, the resistance that an E+B

provides at an given length increases with increasing

length. "o an exercise is harder with a pre-stretched

E+B than with an initiall-slac E+B. While E+Bs are

inexpensive, versatile, lightweight, and unthreatening,

the have disadvantages. irstl, when using E+Bs, an

exercise will differ from a comparable exercise using

free weights as E+Bs are a form of variable resistance.

he <oint moments during elastic resistance training

are a function of the length of the E+B, which is itself

a function of <oint angle in single-<oint exercises and

of <oint angles in multi-<oint exercises. Whether

variable resistance is more or less effective than

isoinertial resistance training for increasing strength,

si9e and power is unclear. "econdl, when stretching

an E+B, most exercises involve taing the E+B from a

shortened state while the prime mover muscles are

lengthened to a lengthened state while the prime

mover muscles are shortened. hus, since the tensile

force exerted b the E+B increases with increasing

length, the difficult of the exercise is greatest when

the E+B is longest and the prime mover muscles are

shortened #i.e. contracted'. his is in contrast to free-

weights exercises, which tend to be most difficultwhen the prime mover muscles are most lengthened.

hus, given that regional hpertroph is nown to

occur in response to exercises where the muscles are

stimulated most at different muscle lengths, E+Bs

could develop muscles in a different wa from the

same exercise performed with free-weights. hirdl,

E+Bs differ from free weights in that it is not eas to

measure how much force is being exerted in order to

perform an exercise. ree weight exercises can be

=uantified b reference to the load #in either pounds

or ilograms' but although E+Bs are graded b color,

it is not eas to now how to progress the loading or

to compare the E+B exercise with a dumbbell exercise.

OBJC!"#$ o assess the effects of a long-term

strength training program using elastic bands on

shoulder muscle strength and power #as measured b

isoinetic shoulder internal and external rotation

tor=ues and powers, using a dnamometer to assess

concentric and eccentric tor=ues and powers between

7% degrees of internal rotation and 8% degrees of

external rotation, at 2% and $6% degreesFs' and ballthrowing speed #as measured b radar gun for both

standing and <umping throws', in oung female

handball plaers.

%O%&'(!"O)$ 78 female handball plaers, randoml

assigned to a strength training #"' group #$&

sub<ects, aged &4.7 5 &.& ears' or a control #13>'

group #&) sub<ects, aged &4.% 5 %.) ears'.

")!*#)!"O)$ he " group performed a strength

training program 7 times per wee, for 2 wees before

regular handball training, while the 13> group did

not. he exercises were performed initiall for 7 sets

of &% repetitions, with 7% seconds of rest between

sets. Exercises were made harder b increasing thenumbers of repetitions to &4 and then $%, increasing

the starting length of the band, and also using heavier

bands. wo exercises were used for internal rotation

strengtheningG &' sidewas standing position with 8%

degrees of shoulder abduction and 8% degrees of

elbow flexion, with the band held at head height, and

$' sidewas standing position with shoulder in neutral

position and elbow flexed at 8% degrees, with the band

held at waist height. In both exercises, the athletes

performed an internal rotation movement through a

full range of motion.

What happened?

Effects on shoulder muscle strength and power

he researchers found that although the " group did

not significantl improve shoulder internal or external

tor=ues compared to the 13> group, although the

did improve shoulder internal rotation power output

significantl compared to the 13> group.

Effects on #all throwing speed

he researchers found that the " group significantl

improved ball throwing speed compared to 13> when

measured in both standing #from 68.7 5 &.6 to 4$.6 5

&.6mFhr' and <umping #from 42.$ 5 &.2 to 2%.2 5

&.6mFhr' postures.

What did the researchers conclude?he researchers concluded that a 2-wee program of

elastic resistance band shoulder internal rotation

training improved shoulder internal rotation power

output and ball throwing speed in oung, female

handball athletes.

'imitations

he stud was limited as it onl tested one training

method, and did not compare this training method

with another, such as conventional resistance training,

or weighted implement throwing.


http://europepmc.org/abstract/med/26812746



8/18/2019 Scr Mar 2016 PDF


*eterogeneity in resistance training$induced muscle

strength and mass responses in men and women of

different ages, #y (htiainen, :alker, Peltonen,

*olviala, %illanp;;, <aravirta, 3 *ulmi, in (ge 5/.7 "

Background

When performing the same resistance trainingprograms, individuals tpicall displa a wide range of

responses. "ome en<o ver large increases in

muscular strength and si9e, while others displa

almost no changes whatsoever. In one of the largest

investigations into the inter-individual variabilit in

strength and si9e gains et performed, it was reported

that the variance between sub<ects in &+ strength

gains ranged from %* to $4%*, while changes in

maximum isometric strength ranged from -7$* to

&68*. win studies have identified that genetic

factors are critical for determining the starting point

for muscular strength and si9e, the changes in

muscular strength and si9e that occur during

development, and the gains in muscular strength and

si9e that result from long-term programs of resistance

training. Even so, despite the extensive use of twin

studies, available methods for exploring the precise

genetic influences on muscle strength and si9e have

been extremel limited until ver recentl. Indeed,

onl in the last few ears have methods become

available for investigating the effect of genetic

polmorphisms on the hpertrophic response to

resistance training. @ess than ten ears ago, at the

time of the $%%2-%: update to he /uman 0ene ap

for ;erformance and /ealth-+elated itness

;henotpes, there was ver little research that could

shed an light on the hpertrophic response to

resistance training. "ince then, researchers have

found that a small number of different genetic traits

and single nucleotide polmorphisms #">;s' ma be

related to a superior increase in muscle mass. an of

these recent trials have made use of data recorded b

the unctional "ingle >ucleotide ;olmorphisms

Associated with /uman uscle "i9e and "trength

#Au""' trial. +ecentl, a summar of the findings

from this data set was produced b the researchers.

In this summar, the reviewers reported on the results

published in relation to &: different genes that were

specificall tested for their association with muscle

strength or si9e. he concluded that with a few minor

exceptions, single variants in genetic polmorphisms

appear to explain onl minor inter-individual variabilit

in the hpertrophic response to resistance training. Itis therefore ver unclear what drives the genetic

differences in muscular strength and si9e between

individuals.

OBJC!"#$ o identif high and low responders to

resistance training, in terms of their changes in

muscle si9e #as assessed b =uadriceps muscle cross-

sectional area measured b ultrasound or magnetic

resonance imaging +IC', lean mass #as assessed b

leg lean mass as measured b using dual-energ N-

ra absorptiometr DENAC', and muscle strength #as

measured b &+ hori9ontal leg press', and to assessthe effects of age #b reference to three groups, being

O64 ears, 64 ( 2% ears, and P2% ears' and sex on

the responsiveness to training.

%O%&'(!"O)$ $): untrained sub<ects #&)7 males

and &%6 females', aged &8 to :) ears, drawn from

&% previousl-performed randomi9ed controlled trials.

")!*#)!"O)$ he resistance training programs

were $% ( $6 wees in duration, and training was

performed $ times per wee.

What happened?

Effect of sex and age on strength gainshe researchers found that across all age groups the

relative increase in &+ hori9ontal leg press after

resistance training was higher in females than in

males #$6.$ 5 &7.) vs. &8.6 5 8.4*' but the absolute

increase in &+ hori9ontal leg press was similar for

females and males #$4.8 5 &:.& vs. $).7 5 &4.:g'.

hese results did not differ between the age groups.

>evertheless, there was a ver high degree of

heterogeneit among both males and females, with

the relative changes in &+ varing from Q)* to 2%*

in the training populations.

Effect of sex and age on si2e gains

he researchers found that across all age groups the

increase in muscle si9e after resistance training wassimilar in males and females #4.& 5 4.8* vs. 6.$ 5

2.7 *'. hese results did not differ between the age

groups. >evertheless, there was a ver high degree of

heterogeneit among both males and females, with

the relative changes in muscle si9e varing from Q:*

to &6*, from Q&&* to $:*, from Q8* to $:* and

from $* to 7%* when measured b DENA, +I,

ultrasound muscle cross-sectional area and ultrasound

muscle thicness, respectivel. urther investigation

with linear regression analsis and using principal

component analsis revealed that no individual factor

#age, sex, and baseline and changes in bod mass

index, changes in &+, and changes in relative &+'

could predict changes in muscle si9e.


he researchers concluded that long-term resistance

training programs involve considerable inter-individual

variation in both the changes in muscle si9e and

strength. In contrast, neither age nor sex were ma<or

predictors of the changes in muscular strength and

si9e following resistance training.

'imitations

he stud was limited as it did not identif an

predictor of the changes in muscle si9e and strength.




8/18/2019 Scr Mar 2016 PDF


!enetic varia#ility among power athletes) 'he

stronger vs= the faster, #y &en$>aken, Eliakim,

Nemet, 3 Meckel, in 'he Journal of %trength 3

+onditioning 4esearch 5/.7 "

Background

When performing the same resistance trainingprograms, individuals tpicall displa a wide range of

responses. "ome en<o ver large increases in

muscular strength and si9e, while others displa

almost no changes whatsoever. or a detailed

introduction to inter-individual variabilit in the

responsiveness to resistance training, see the earlier

stud review.

OBJC!"#$ o compare the genetic characteristics

between subtpes of anaerobic athletes #as measured

b blood drawn and sub<ected to a=man allelic

discrimination assa'.

%O%&'(!"O)$ :& sprinters and <umpers #+A1R', 46

weightlifters #WEI0/' and )2 control sub<ects #13>'.

")!*#)!"O)$ Blood was sampled and sub<ected

to analsis in respect of 7 genetic variantsG A1>7

+4::N, which is associated with muscle contractions,

A0 et$74hr which is associated with muscle

growth, and ;;A+D F1, which is associated with

aerobic capacit.

What happened?

+omparison #etween athletes

he researchers found that the fre=uenc of the

A1>7 ++- genotpe was significantl higher among

+A1R #78.6*' compared to WEI0/ #$$.$*' and

13> #&).2*'. he researchers found that the A0

et$74hr genotpe fre=uencies were significantldifferent between WEI0/ and +A1R, and between

WEI0/ and 13>. "pecificall, the A0 hrhr

genotpe was significantl higher among WEI0/

#$4.8*' compared to +A1R #6.$*' and 13>

#&$.)*'. inall, the found that the ;;A+D $861

genotpe fre=uencies did not differ between groups.


he researchers concluded that some genetic mae-

ups ma predispose an athlete to excel at either the

velocit-end of the force-velocit spectrum #sprinting

or <umping', or the force-end of the force-velocit

spectrum #weightlifting'.

'imitations

he stud was limited insofar as weightlifting is still

closer to the velocit-end of the force-velocit

spectrum than some other strength sports, such as

powerlifting and strongman, and no athletes in these

categories were anal9ed.


http://journals.lww.com/nsca-jscr/Abstract/publishahead/Genetic_variability_among_power_athletes___The.96588.aspx

http://journals.lww.com/nsca-jscr/Abstract/publishahead/Genetic_variability_among_power_athletes___The.96588.aspx

8/18/2019 Scr Mar 2016 PDF


Influence of different speeds of muscle actions in the

maximum dynamic strength, in the maximum volume

of repetitions, and rated perceived exertion, #y %ou2a,

+ampos, Moreira, !uimar?es, %ilva, 3 %ilva, in Journal

of Exercise Physiology 0nline 5/.7"

BackgroundIntroduction

he optimal structure of a resistance training program

is unclear. an variables can be altered, including

relative load, volume, fre=uenc, proximit to

muscular failure, rest period duration, muscle action

and repetition speed. Bar speed is particularl difficult

to interpret, as it naturall alters repetition duration

#time under tension'. Additionall, the research

regarding bar speeds is hard to anal9e, as studies

using isoinetic #variable load' training methods often

produce different results from those using constant

load training methods.

Effect of #ar speed on strength gains read more "

"everal long-term trials have assessed the effects of

different bar speeds on strength gains during

conventional constant-load resistance training in

various populations. At our last count, at least &&

studies have compared the effects of fast and slow bar

speeds on strength gains over long-term interventions

in untrained sub<ects. his research is relativel clear

that faster bar speeds are superior to slower bar

speeds for strength gains, as 2 of these && trials found

that faster bar speeds led to significantl greater

strength gains than slower bar speeds and man of

the remaining studies reported non-significant trends

in the same direction. or trained sub<ects, there is

much less research available. At our last count, at

least 7 studies had been performed, of which & found

a significant benefit of using faster bar speeds. hus,

it seems appropriate that current guidelines do

recommend faster bar speeds during resistance

training in order to achieve optimal strength gains.

Effect of #ar speed on hypertrophy read more "

A small number of long-term trials have assessed the

effects of different bar speeds on si9e gains during

conventional constant load resistance training in

various populations. At our last count, at least :

studies have compared the effects of fast and slow bar

speeds on si9e gains over long-term interventions in

untrained sub<ects. his research is unclear, as $ of

these : trials found that slow bar speeds led to

significantl greater si9e gains than fast bar speeds.

or trained sub<ects, there is little research available.

hus, it is currentl ver difficult to mae an firm

recommendations about the best bar speed to use for

hpertroph.

OBJC!"#$ o investigate the influence of different

concentric and eccentric bar speeds #as measured b

duration of each phase of the repetition' on the

maximum volume of repetitions performed, the rating

of perceived exertion #+;E', and maximum dnamic

muscle strength after :$ hours post-worout #as

measured b &+ "mith machine s=uat', in females.

%O%&'(!"O)$ 8 females, aged $$ 5 &.) ears, with

resistance training experience and a &+ "mith

machine s=uat of &%7 5 $&g.

")!*#)!"O)$ "ub<ects performed "mith machine

s=uats for 7 sets to concentric muscle failure with

2%* of &+, with a rest interval of 8% seconds

between sets. he performed s=uats in 7 conditions

with the same total repetition duration #6 seconds' but

differing phase durationG #&' 7-second concentric and

&-second eccentricM #$' &-second concentric and 7-

second eccentricM and #7' $-second concentric and $-

second eccentric.

What happened?

+omparison #etween #ar speeds

he researchers found no significant differences

between the conditions in respect of the maximum

volume of repetitions performed, in respect of the +;E

recorded b the sub<ects after each worout, and in

respect of the maximum dnamic muscle strength

recorded at :$ hours post-worout.


he researchers concluded that resistance training

worouts performed with differing phase durations but

with similar total repetition duration did not differ in

respect of the total number of repetitions performed,the +;E, or the loss in strength after :$ hours. his is

in contradiction to previous research, which indicates

that greater stress on the eccentric phase tpicall

involves lower +;E but greater losses in strength post-

worout because of increased muscle damage.

'imitations

he stud was limited b the small sample si9e and b

the use of onl one exercise. Different results might

be observed if a larger number of sub<ects had been

tested or if different exercises had been used.


http://www.strengthandconditioningresearch.com/strength/#8a

http://www.strengthandconditioningresearch.com/hypertrophy/#8





8/18/2019 Scr Mar 2016 PDF


%elective effects of training against weight and inertia

on muscle mechanical properties, #y 8juric, +uk,

%reckovic, Mirkov, Nedeljkovic, 3 Jaric, in the

International Journal of %ports Physiology and

Performance 5/.7 "

BackgroundIntroduction

he optimal structure of a resistance training program

is unclear. an variables can be altered, including

relative load, volume, fre=uenc, the proximit to

muscular failure, rest period duration, muscle action

and repetition speed. During resistance training, the

tpe of external load can be changed but this has onl

rarel been explored. In general, the tpe of external

load can be divided into tpes where the load remains

the same throughout the movement #isoinertial' and

tpes where the load varies during the movement

#variable'. Jariable tpes of resistance can be further

subdivided into tpes were the load changes in order

to maintain a constant velocit during the exercise#isoinetic' and those in which the load is altered to

follow the force-angle curve more generall #strictl

variable, but sometimes also called accommodating

resistance'.

Effects of varia#le resistance on strength gains

Jarious researchers have investigated the differences

in effects on strength gains during long-term periods

of resistance training using either constant load or

variable load resistance tpes, while training with

barbells. In such cases, the variable loads are created

b the use of either bands or chains. o date, at least

4 studies have been performed in resistance-trained

sub<ects. /owever, among these studies, onl & has

reported a superior benefit on strength gains of using

variable resistance tpes compared to using constant

load resistance. he use of variable resistance or

constant loads ma therefore mae little difference to

strength gains in trained sub<ects. "imilarl, to date,

onl & stud has been carried out assessing the

difference in the effect on strength gains between

constant load or variable load resistance tpes, while

training with barbells in untrained sub<ects. In this

stud, there was no difference between the variable

and the constant load resistance tpe. herefore,

despite the huge popularit of variable resistance, the

addition of bands and chains ma not be superior to

constant loads for resistance trained and untrained

populations. Whether benefits might be observed inelite powerlifters, however, is unclear.

OBJC!"#$ o compare the effects of training

against different tpes of external load #weight onl,

weight plus inertia, or inertia onl' on changes in

maximum muscle force #', velocit #J', and power

output, assessed b reference to changes in the -J

profile #as measured b recording and J when lifting

) different loads ranging between 7% ( :8* of &+'.

%O%&'(!"O)$ 6) untrained, male phsical education

students, aged $%.4 5 $.% ears, randoml allocated

to either a weight onl #W' group, a weight plus

inertia #WI' group, an inertia onl #I' group, or a

non-training control #13>' group.

")!*#)!"O)$ All sub<ects performed an )-wee

program of bench throws, training 7 times per wee

and using 2 ( 8 sets of : reps. When holding a load

static, the force re=uired is e=ual to its mass #m'

multiplied b gravit #g'. his force is nown as

weight #W'. o accelerate that same load, an

additional force is re=uired that changes its velocit,

which from a standing start is e=ual to its mass #m'

multiplied b the rate at which it is accelerated #a',which is nown as inertia #I'. herefore, normal

barbell bench presses or bench throws involve both W

and I. In contrast, machine-based resistance that

produces a fixed resistance irrespective of the point in

the range of motion onl involve W and have no I.

inall, trul ballistic movements involving implements

with little mass have negligible W and the onl

relevant force is produced b I.

What happened?

+hanges in @, 9 and power output

he researchers observed a significant increase in

maximum theoretical #%' in the W group and in the

WI group. In contrast to this, the observed a

significant increase in maximum theoretical J #J%' in

the I group and in the WI group. All groups improved

maximal power output #;%', although while the gain in

;% in the WI group was achieved b an increase in

both % and J%, the same gain in ;% in the I group was

achieved entirel b the improvement in J%, while the

gain in the W group was attained exclusivel through

an increase in %.


he researchers concluded that although training

using different tpes of external load #W, WI or I'

can all enhance maximal power output to a similar

extent, the achieve this goal b different gains in

maximal force or maximal velocit. +emoval of the

inertial component of the resistance #as is often done

b using machine-based variable resistance' might be

more effective for enhancing maximum force, while

removal of the weight component #as is often done b

using ballistic movements with light loads' might be

most effective for enhancing maximal velocit.

'imitations

he stud was limited as it is unclear whether the

absolute load used would have an effect on the

results achieved.




8/18/2019 Scr Mar 2016 PDF


'he effects of frontal$ and sagittal$plane plyometrics

on change$of$direction speed and power in adolescent

female #asket#all players, #y Mc+ormick, *annon,

Newton, %hult2, 8etling 3 Aoung, in International

Journal of %ports Physiology and Performance 5/.7 "

Backgroundhe term Hplometrics was first populari9ed with the

"oviet <umping coach, Jeroshans. Jeroshans

wanted to explore was to develop the <umping abilit

of athletes who had alread attained significant gains

using standard methods at the time, which mainl

comprised <umping practice and resistance training.

Jeroshans reasoned that since there seemed to be

a correlation between short ground contact times and

better performances in triple <umpers, this could impl

that a greater stiffness #or a superior abilit to store

and release elastic energ' could be the e to

improved <umping abilit. hus, he started using depth

<umps with his athletes in order to increase their

abilit to switch from eccentric muscle actions to

concentric muscle actions more =uicl, thereb

reducing ground contact times. While man coaches

still thin of plometrics in these terms, the usage in

the modern literature has changed substantiall.

oda, the term plometrics refers to explosive,

compound upper- or lower-bod movements involving

the stretch-shortening ccle. When considering the

lower-bod, various different tpes of <umps are

included within this definition and for the upper-bod,

medicine ball throws are a fre=uent example. here is

therefore a difference between the earliest popular

usage of the term b Jeroshans and his later

disciples and the modern sports science literature,

which seems to use the term as a subset of ballistic

resistance training exercises, being those using ver

low-loads or no-load and which involve the stretch-

shortening ccle. oreover, it is often stated that such

plometrics are the e to bridging the =ualities of

strength and power. hus, there is also a difference

between the intended purpose of plometrics between

the earl popular usage and usage in modern sports

science, as Jeroshans intended the training

modalit to improve <umping performance, while

modern literature expressl refers to increases in

muscular power. If Jeroshans was correct and the

means b which plometrics improves <umping

performance is b increasing stiffness, then we might

not necessaril expect to see substantial changes in

power, or at least we might see smaller changes thanb other training modalities. nfortunatel, there are

ver few long-term trials comparing the use of

plometrics to other training modalities in relation to

improving muscular power output. /owever, there are

a great man long-term trials demonstrating that

plometrics do consistentl increase both muscular

power and vertical <umping abilit. Additionall,

plometrics appears to lead to increases in muscle si9e

as well as enhancements in neural drive, despite

assertions to the contrar b coaches lacing in

nowledge of the literature.

OBJC!"#$ o compare the long-term effects of

frontal plane and sagittal plane plometric training

programs on changes in countermovement vertical

<ump #1K' height, standing long <ump #"@K' distance,

lateral hop #@/' distance, and lateral-shuffle test #@"'

abilit, in basetball plaers.

%O%&'(!"O)$ &6 female high-school basetballplaers, aged &2.%% 5 %.:) ears, randoml allocated

to either a frontal plane #;' group or a sagittal plane

#";' group.

")!*#)!"O)$ All sub<ects trained using a long-

term program of plometrics, involving both unilateral

and bilateral exercises. he ; group used onl

exercises in the frontal plane, while the sagittal plane

group used onl exercises in the sagittal plane.

What happened?

+hanges in +MJ height and %J distance

he researchers found that the "; group improved

1K height b more than the ; group, but there wasno difference between groups in respect of the

changes in "@K distance. 3verall, however, both

groups improved in both measures.

+hanges in * distance and %' performance

he researchers found that the ; group improved @/

#left' distance and @" #left' performance b more

than the "; group, but there was no difference

between groups in respect of the changes in either @/

#right' distance or @" #right' performance. 3verall,

however, both groups improved in all measures.


he researchers concluded that both frontal plane and

sagittal plane plometrics are effective for improving

vertical, hori9ontal, and lateral <umping performance,

as well as change-of-direction abilit. /owever, the

also concluded that frontal plane plometrics are more

effective for lateral <umps and change-of-direction

abilit, while sagittal plane plometrics are more

effective for improving vertical <umping.

'imitations

he stud was limited in that onl one measure of

change-of-direction performance was used, and the

same results might not be observed with other tests.




8/18/2019 Scr Mar 2016 PDF


Effect of superimposed electromyostimulation on #ack

extensor strengthening) a pilot study, #y Park, %eo, 3

ee, in 'he Journal of %trength 3 +onditioning

4esearch 5/.7 "

Background

>euromuscular electrical stimulation #>E"' traininghas previousl been proposed as a tool to help reduce

losses in muscle mass during periods of limb

immobili9ation. >E" involves the invoing of

involuntar, isometric contractions of specific muscle

groups at a relativel low intensit. his techni=ue can

be used even in the in<ured limb under certain

circumstances. +esearchers have found that b using

a relativel high fre=uenc #&%%/9' and pulse width

#6%%Ss' the otherwise significant muscle atroph that

occurs in the first 4 das of limb immobili9ation can be

avoided or at least reduced b means of using twice-

dail, 7%-minute sessions of >E". Additionall,

studies have reported that muscular strength can be

improved using >E" during periods of rehabilitation

even where limbs are not immobili9ed, such as

following surger for an in<ur. While >E" is

generall performed in con<unction with isometric

muscle actions, it is also possible to use it in

combination with either concentric or eccentric muscle

actions, which ma be more beneficial for improving

full <oint range-of-motion strength measures.

OBJC!"#$ o compare the effects of bac extension

resistance training with and without superimposed

>E" in health adults on bac extension tor=ue #as

measured in an isoinetic dnamometer at both at 2%

and &)% degreesFs' and bac extension endurance

#measured using the "orensen test'

%O%&'(!"O)$ $% health, non-athletic, male adultswith no histor of low bac pain in O& ear, aged $% (

$8 ears, randoml allocated to either an >E" group

or to a placebo #;@A1' group.

")!*#)!"O)$ All sub<ects performed a $-wee

program of bac extension resistance training exercise

using a "wiss ball, for $ sets of &% repetitions, 4 times

a wee. In the >E" group, electrodes were attached

bilaterall to the lumbar paraspinal muscles #at the @$

and @6 vertebrae'. he stimulation intensit was set to

the maximal tolerable intensit. >E" was super-

imposed for &% seconds followed b a $% second rest

period. he same protocol was used in the ;@A1

group, but the stimulation intensit was set at the

lowest possible intensit #4mA'.

What happened?

+omparison of effects on strength

he researchers found that pea bac extension

tor=ue at both 2% and &)% degreesFs increased

significantl in both groups. Although there was a

tendenc for >E" to increase pea bac extension

tor=ue to a greater extent than ;@A1 #)%.& 5 6&.8 vs.

68.6 5 4$.6>m' at 2% degreesFs, and at &)%

degreesFs #)8.: 5 :&.: vs. 42.6 5 26.7>m', there

was no significant difference between the two groups.

+omparison of effects on endurance

he researchers found that bac extension enduranceincreased significantl in both groups. Although there

was a tendenc for >E" to increase bac extension

endurance to a greater extent than ;@A1 #7).2 5 $8.&

vs. $&.8 5 $4.: seconds', there was no significant

difference between two groups.


he researchers concluded that over a $-wee period,

there was no clear beneficial effect of >E" during

bac extension training using a "wiss ball. /owever,

given the large non-significant results, this might have

been tpe II error, and different findings might be

achieved with a longer stud duration or a larger

sample si9e.

'imitations

he stud was limited b the short duration of the

training period at onl $ wees. Different results might

be observed with a longer training period.




8/18/2019 Scr Mar 2016 PDF


'he effect of high$intensity interval cycling sprints

su#seBuent to arm$curl exercise on muscle strength

and hypertrophy in untrained men) a pilot study, #y

<ikuchi, Aoshida 3 Naka2ato, in 'he Journal of

%trength 3 +onditioning 4esearch 5/.6 "

BackgroundAlthough several previous studies have found that

concurrent training can lead to inferior gains in

muscular strength, si9e and power in comparison with

resistance training alone #which is called the

Hinterference effect', it is unclear exactl wh this

happens. +eviews have concluded that the inferior

gains differ between =ualities, with gains in muscular

power being most maredl reduced b concurrent

training, but gains in muscular si9e being affected ver

little. "uch reviews have found that the extent to

which concurrent training leads to inferior adaptations

ma also be mode- and intensit-dependent. A greater

interference effect has been observed between aerobic

exercise and resistance training where the mode of

aerobic exercise is long-distance running, while long-

distance ccling appears to have ver minor adverse

effects and ma even have beneficial effects on

=uadriceps muscular si9e. hus, attempts to discern a

molecular pathwa for the interference effect that

ignores these apparent differences between aerobic

exercise modes ma be flawed. "imilarl, greater

interference effects have been observe where aerobic

exercise is performed for longer periods with lower

levels of intensit, while less substantial effects have

been observed where the aerobic exercise is of shorter

duration and higher intensit. It is possible that one

factor involved in the interference effects observed

during concurrent training ma arise from functional

or non-functional overreaching, which ma lead to

accumulated fatigue such that performance in tests of

muscular strength and power is impaired. his might

explain wh gains in muscular si9e are least affected

b concurrent training and wh power is most strongl

affected.

OBJC!"#$ o assess whether adding lower-bod

sprint interval training #"I' on a ccle ergometer

after upper-bod resistance training produces an

interference effect in respect of arm muscle strength

#as measured b &+ machine biceps curl' and

hpertroph #as measured b muscle cross-sectional

area, recorded b magnetic resonance imaging #+I'

scans at 4%* of upper arm, &% mm distal and &% mmproximal', and to record changes in J3$-max #as

measured during a maximal graded exercise test on a

ccle ergometer'.

%O%&'(!"O)$ &6 Kapanese male sub<ects, aged $% 5

&.) ears, randoml allocated to either a resistance

training onl #+3' group or to a concurrent training

#13>1' group.

")!*#)!"O)$ "ub<ects in both +3 and 13>1

groups performed the same )-wee resistance training

program, involving 7 sets of &% repetitions with )%*

&+ of machine biceps curl exercise, 7 times per wee

on nonconsecutive das. In addition, the sub<ects in

the concurrent training group also performed "I aftereach resistance training worout, comprising 6 sets of

7%-second maximal effort ccling sprints, separated b

6 minute and 7%-second rest intervals.

What happened?

+omparison of effects on strength

he researchers observed a significant increase in &+

in the +3 group but not in the 13>1 group, although

effect si9es were large in both #&.4: and &.&8', which

suggests that this latter failure to identif a finding

was most liel tpe II error. Even so, the larger effect

si9e in the +3 group compared to the 13>1 group

indicates the presence of an interference effect.

+omparison of effects on hypertrophy


muscle cross-sectional area in the +3 group but not

in the 13>1 group, although effect si9es were large in

both #&.68 and &.%&', which suggests that this latter

failure to identif a finding was most liel tpe II

error. Even so, the larger effect si9e in the +3 group

compared to the 13>1 group indicates the presence

of an interference effect.


he researchers concluded that performing concurrent

upper-bod strength training and lower-bod sprint

interval training on the same da produces aninterference effect in respect of both muscle strength

and hpertroph, which is presumabl due to sstemic

factors.

'imitations

he stud was limited in that the sample si9e was

liel too small for the statistical analsis, and also in

that no third group was incorporated that trained

using upper-bod sprint interval training.




8/18/2019 Scr Mar 2016 PDF


&ilateral practice improves dominant leg performance

in long jump, #y @ocke, %pancken, %tockinger, 'hCrer,

3 %tein, in European Journal of %port %cience 5/.7 "

Background

rac and field is a collection of competitive phsical

events that fits within a larger bod of events calledathletics. rac and field is contested both outdoor and

indoor and the events incorporated under its umbrella

comprise those that re=uire sill in running, <umping

and throwing. rac events are those that involve

running while field events are those that involve either

<umping or throwing. he running events comprise the

sprint, middle and long distances and range from 2%m

to &%,%%%m. "print distances are those ranging from

2%m to 6%%m. iddle distances are those ranging

from )%%m to &4%%m #or perhaps also the 7,%%%m'

and long distance are those ranging from 7,%%%m to

&%,%%%m. +unning events can be contested either with

or without hurdles but the distances differ depending

on whether hurdles are present. +unning events can

also be contested in teams of athletes, as relas.

Kumping events include bilateral and unilateral <umps

in hori9ontal and vertical directions both with and

without implements and are contested as the long

<ump, triple <ump, high <ump and pole vault. hrowing

events differ predominantl depending on the weight

of the implement being thrown but also on the

throwing techni=ue and are contested as the shot put,

<avelin, discus and hammer. 1ombinations of these

events are organi9ed into separate competitions for

athletes who excel as all-rounders, which include the

decathlon, heptathlon and pentathlon. he decathlon

comprises the &%%m sprint, the long <ump, the shot

put, the high <ump, the 6%%m sprint on a single da of

competition, followed b the &&%m hurdles, the

discus, the pole vault, the <avelin, and the &4%%m run

on a second da. he heptathlon comprises the &%%m

hurdles, the high <ump, the shot put, the $%%m sprint

on a single da of competition, followed b the long

<ump, the <avelin, and the )%%m run on a second da.

he pentathlon is contested on a single da and

comprises the &%%m high hurdles, long <ump, shot

put, high <ump, and )%%m run. In general, except for

the middle and long distance running events, most

trac and field events re=uire a considerable amount

of strength and power in order to excel at a high level

and therefore most training programs for the trac

and field events will include resistance training,

ballistic resistance training, andFor plometrics inorder to develop athletes to their full potential. In

addition, man athletes will continue to perform a

great deal of sill practice and drills intended to

improve the efficienc of movements.

OBJC!"#$ o assess whether training with the non-

dominant leg produces a cross-over training effect

when training for the long <ump #as measured b the

best distance recorded over 7 long <umps', in outh

trac and field athletes.

%O%&'(!"O)$ 7& girls and 7% bos, aged 8.: 5 $.%

ears, recruited from a local athletic club, with 7.2 5&.:2 ears of experience in athletics and accomplished

in performing the long <ump. "ub<ects were randoml

allocated into either a dominant-leg single-leg tae-off

group #>I' or to a bilateral <umping practice group

#BI@'.

")!*#)!"O)$ "ub<ects performed a &$-wee

training period, in which the trained for the long

<ump $ times per wee for &.4 hours on each da

#uesda and rida' in an indoor sports hall. Each

group #>I and BI@' completed the same practice

worload but >I performed all exercises of the

specific long <ump practice with the dominant leg,

while BI@ alternated between the dominant and non-

dominant legs, in a randomi9ed order.

What happened?

+omparison #etween DNI and &I groups

he researchers found that the sub<ects in both >I

and BI@ groups improved long <ump performance.

/owever, the increase in BI@ was greater than the

increase in >I #4.$ vs. 7.6*'.


he researchers concluded that long <umping practice

with both the dominant and non-dominant legs was

superior to long <umping practice with onl the

dominant leg over a &$-wee period. his ma bebecause training with both legs involves the presence

of a cross-over effect produced through as et unclear

central adaptations.

'imitations

he stud was limited as it was performed in ver

oung athletes and different results might be found in

older individuals.


http://www.tandfonline.com/doi/abs/10.1080/17461391.2016.1141996


8/18/2019 Scr Mar 2016 PDF


'he importance of muscular strength in athletic

performance, #y %uchomel, Nimphius, 3 %tone, in

%ports Medicine 5/.7 "

Background

"trength is defined as the abilit to express force

through the production of <oint moments. here areman different conditions affecting the wa in which

strength is displaed. "trength can be displaed

maximall or sub-maximallM it can be displaed

isometricall #without moving' or dnamicall #while

moving'M during isometric tests strength can be

displaed at different <oint ranges of motion #leading

to long or short muscle lengths'M it can be displaed at

a single <oint #in isolation exercises' or at multiple

<oints #in compound movements'M it can be displaed

against an external resistance that has a constant load

#isoinertial' or against a changing external resistance

#variable, accommodating or isoinetic'. In addition,

when exerted dnamicall, strength can be exerted

either while the involved muscle is lengthening or

shortening, which are referred to as concentric or

eccentric muscle actions. "trength gains are thought

to arise from a combination of factors, including both

central and peripheral origins. 1entral mechanisms

refer to adaptations that occur within the central

nervous sstem, while peripheral mechanisms refer to

adaptations that occur within the muscle itself. It is

unclear to what extent each of the central and

peripheral adaptations affect strength gains during

resistance training programs. here are indications

that the main factor influencing gains in strength is

hpertroph. /owever, other peripheral factors also

appear important, as specific tension explains some of

the inter-individual variabilit in strength gains.

"pecific tension seems to be driven partl b changes

in extracellular lateral force transmission and partl b

changes in mofibrillar pacing densit, which are

alterations that occur at the level of the individual

muscle fiber. 3ur understanding of the central factors

that affect strength is ver limited. raditionall, it has

been assumed that large changes in agonist activit or

agonist-antagonist co-activation occurred but in realit

these are small. While inter-muscular co-ordination

has not been widel studied, it is possible that this

ma prove to be the largest single central factor

affecting strength gains, as man other possibilities

have been discounted. When performing the same

resistance training programs, individuals tpicall

displa a wide range in the si9e of their adaptations,which is termed Hheterogeneit of responsiveness.

"ome people en<o ver large increases in strength,

while others displa almost none. In one of the largest

investigations into the inter-individual variabilit in

strength gains et performed, it was reported that the

variance between sub<ects in &+ strength gains

ranged from &+ strength gains ranged from % (

$4%*, while changes in maximum isometric strength

ranged from -7$* to &68*. win studies have

further identified that genetic factors are critical for

determining the starting point for muscular strength

and the strength gains that result from training.

OBJC!"#$ o review the literature exploring the

influence of muscular strength on factors associated

with athletic performance.

What happened?

Power and rate of force development 4@8"

he reviewers note that both muscular power and +Dare considered to be important factors that are closel

associated with athletic performance. he note that

as man as 4: associations have been calculated

between strength and +D, with 8:* of these finding

at least a positive, moderate relationship, and :4* of

them reporting at least a positive, large relationship.

Also, the reviewers identified that &:: associations

have been calculated between strength and power,

with :2* displaing at least a positive, moderate

relationship, and 24* displaing at least a positive,

large relationship.

Jumping, sprinting and change of direction +08"

he reviewers note that <umping abilit, sprint running

speed, and 13D performance are each considered tobe important factors that are closel associated with

athletic performance. he note that as man as &&2

associations have been calculated to assess the

relationship between strength and both hori9ontal and

vertical <umping abilit, of which :)* displaed at

least a positive, moderate relationship, and 48*

displaed at least a positive, large relationship. he

also note that as man as 2: associations have been

calculated to assess the relationship between strength

and sprint running speed, of which )4* displaed at

least a positive, moderate relationship, and 22*

displaed at least a positive, large relationship. inall,

in respect of 13D performance, the note that as

man as 64 associations have been calculated toassess the relationship between strength and 13D

performance, of which :)* displaed at least a

positive, moderate relationship, and 2%* displaed at

least a positive, large relationship.


he researchers concluded that muscular strength is

moderatel-to-strongl correlated to superior

muscular power output, +D, <umping abilit, sprint

running speed, and 13D performance. hese

correlations suggest that the development of muscular

strength should be paramount for the improvement of

sports performance.

'imitations

he review was limited as it was a narrative stud

performed b one group of authors, and their views

ma not reflect those of all researchers woring in the

same field.


http://link.springer.com/article/10.1007/s40279-016-0486-0


8/18/2019 Scr Mar 2016 PDF


+entral and peripheral fatigue during resistance

exercise a critical review, #y >ajFc, +halimoniuk,

Mas2c2yk, !oGaH, 3 angfort, in Journal of *uman

<inetics 5/.7 "

Background

1onventionall, muscular fatigue is subdivided intotwo aspects, central and peripheral. 1entral fatigue

refers to processes that occur proximall to the

neuromuscular <unction, while peripheral fatigue refers

to processes that occur distall to the neuromuscular

<unction. It is most straightforward to thin of central

fatigue as occurring spinall or supra-spinall and

peripheral fatigue as occurring within the muscle itself.

In order to investigate these two different tpes of

fatigue, researchers have developed a range of tools.

1entral fatigue is commonl explored using the twitch

interpolation techni=ue, which involves evoing

muscular twitches through electrical stimulation during

a maximal voluntar isometric contraction #JI1'.

/owever, there are various other methods that can be

used to explore both central and peripheral fatigue.

ranscranial magnetic stimulation #"' is a method

that is often used, and allows researchers to measure

corticospinal excitabilit with motor evoed potentials

#E;s' and also the superimposed twitch responses.

In general, previous studies have found that the si9e

of E;s increases as a result of exercise-induced

muscle fatigue. /owever, not all studies have found

this same result. he central activation ratio #1A+'

and evoed pea twitch force #;' can also separate

out the central fatigue #i.e. motor neuron firing' and

peripheral fatigue #e.g. excitation-contraction

coupling' elements of overall fatigue. ; is tpicall

calculated as the pea change in force during

passivel stimulated muscular contractions #i.e. the

muscle is relaxed prior to the electrical stimulus' from

the pre-stimulated values recorded in a dnamometer.

1A+ is tpicall calculated in a similar wa but is

different in e respects. irstl, electrical stimulation

of the muscle is performed while the muscle is

contracting and not relaxed. "econdl, it is calculated

as the ratio of pea voluntar force #prior to the

stimulation' to the pea electricall stimulated force

and not as the change. hese measurements are

useful in this context, as it is possible that heav,

moderate and light loads lifted with maximal velocit

could lead to different components of overall fatigue

and therefore give rise to differing responses.

OBJC!"#$ o perform a narrative review of the

literature exploring the roles of peripheral and central

fatigue during resistance training.

What happened?

Peripheral fatigue

he reviewers note that immediatel post-exercise,peripheral changes occur within muscles that are

reflective of peripheral fatigue, including decreases in

intramuscular glcogen, phosphocreatine, adenosine

triphosphate #A;' stores, and an increase in inorganic

phosphate and hdrogen ions. It is noted that these

changes are greater when the exercise is performed

closer to muscular failure. Interestingl, the note that

there is some evidence for the existence of a common

phsiological mechanism between muscle fatigue and

pain, insofar as nociceptive afferent input could be

instrumental in reducing neural drive. he reviewers

point out that A;, inorganic phosphate and / ions

are all able to produce effects at the cellular level on

group III and IJ muscle afferent nerves. he group III

afferents are stimulated mainl in response to tension

within the muscle, while group IJ afferents are

primaril sensitive to metabolic disturbances. hese

nerves signal to the brain during exercise to increase

cardiovascular activit, though elevated smpathetic

nervous sstem #">"' activation. urthermore, the

reviewers note that there are indications that the

onset of low oxgen levels, which are associated with

the development of high levels of lactate production

and the generation of / ions, ma be a primar

trigger for the increase in afferent signaling. his ma

also parallel the point at which tpe II muscle fibers

are recruited.

+entral fatiguehe reviewers explain that there are a number of

possible mediators of central nervous sstem #1>"'

fatigue, although the are all liel at higher levels of

spinal function than the neuromuscular <unction. he

note that there has been much less research into the

nature of central fatigue in comparison with peripheral

fatigue in resistance training, and in order to draw an

inferences it is often necessar to extrapolate from

studies involving other modalities of exercise, such as

endurance training. "uch studies have indicated that

levels of nitric oxide, as well as levels of other 1>"

monoamines #such as serotonin #4-/', dopamine,

and noradrenaline' ma all affect central fatigue b

acting on neurotransmitters.


he researchers concluded that the peripheral and

central mechanisms underling muscular fatigue

during resistance training have not been well-studied,

and further research is urgentl needed.

'imitations

he review was limited as it was a narrative stud

performed b one group of authors, and their views

ma not reflect those of all researchers woring in the

same field.


http://journals.indexcopernicus.com/abstract.php?icid=1187726

http://journals.indexcopernicus.com/abstract.php?icid=1187726

8/18/2019 Scr Mar 2016 PDF


Non‐local muscle fatigue) effects and possi#le

mechanisms, #y *alperin, +hapman, 3 &ehm, in

European Journal of (pplied Physiology 5/.6 "

Background

1onventionall, muscular fatigue is subdivided into

two aspects, central and peripheral. 1entral fatiguerefers to processes that occur proximall to the

neuromuscular <unction, while peripheral fatigue refers

to processes that occur distall to the neuromuscular

<unction. It is most straightforward to thin of central

fatigue as occurring spinall or supra-spinall and

peripheral fatigue as occurring within the muscle itself.

or a detailed introduction to muscular fatigue, see

the earlier stud review.

OBJC!"#$ o perform a narrative review of the

phenomenon of non-local muscle fatigue #>@'

#defined as muscle fatigue observed in contralateral or

even more remote muscle groups not sub<ected to

fatiguing exercise'.

S!&+, S'C!"O)$ "tudies were included where the

reported trial included a fatiguing exercise for P&muscle group, followed b a performance test for P&

different #non-local' muscle group, which itself was

not sub<ected to an fatiguing exercise, where the

non-local muscle group was not an antagonist to the

exercised muscle group, and where the sub<ects in the

stud were both health and phsicall active.

What happened?

%tudies selected

he researchers found a total of 74 relevant studies,

which included 4) performance measures across a

range of different outcome measures. he noted that

the ma<orit of the studies included onl a small

number of sub<ects, and onl &2 of the 74 studiesincluded a control condition.

0#servations

3verall, the researchers noted that the literature is

conflicting. /alf of the studies found the existence of a

>@. /owever, most of the studies that investigated

the lower bod found >@ effects #:2*' but onl a

minorit of studies that examined the upper bod

found >@ effects #7$*'. hese results suggest that

there is some mechanism causing a muscle-group

specific effect of >@. In addition, the reviewers

noted that high-intensit muscle contractions produce

larger >@ effects #in the lower bod' than low-

intensit contractions, that isometric and cclical

contractions cause larger >@ effects than dnamic

contractions, and that bilateral fatiguing exercise

produces larger >@ effects than unilateral exercise.

he also found that males tend to displa greater

>@ effects than females, but the effects of training

status remain unclear.

Mechanisms

he reviewers observed that it is well-nown that

fatiguing exercise protocols activate group III and IJ

muscle afferents, which liel reduce neural drive to

exercises muscles, and possibl also non-exercised

muscles, which ma be at least partl responsible for

the >@ effect. /owever, there are also a range of

other possible mechanisms, including the sstemiccirculation of metabolites, the activation of stabili9er

muscles, and an increase in the perception of effort.


he researchers concluded that there are conflicting

findings in respect of >@, but these could be

explained b confounding factors.

'imitations

he narrative review was limited as it was performed

b one group of authors, and their views ma not

reflect those of all researchers woring in this field.




8/18/2019 Scr Mar 2016 PDF



2% +IOMECHANICS AND MOTOR CONTROL


8/18/2019 Scr Mar 2016 PDF



(n examination of muscle activation and power

characteristics while performing the deadlift exercise

with straight and hexagonal #ar#ells, #y +amara,

+o#urn, 8unnick, &rown, !alpin, 3 +osta, in 'he

Journal of %trength 3 +onditioning 4esearch 5/.7"

Backgroundhe deadlift is an exercise performed b lifting a

barbell resting on the ground. It is a common exercise

for developing lower bod strength and si9e for both

athletes and bodbuilders, as well as being contested

as part of the three lifts in powerlifting. It differs from

most other barbell exercises in that the first part of

the lift involves mostl concentric muscle actions and

the second part of the lift involves mostl eccentric

muscle actions. hus, there is no stretch-shortening

ccle in operation for at least the first repetition of a

set of deadlifts. uch less research has been

performed into the deadlift in comparison with the

bac s=uat. /owever, some studies have compared

the biomechanics of the deadlift with the bac s=uat

and noted large differences. ost notabl, the deadlift

appears to involve a se=uential order of <oint angle

movements, with consecutive nee extension and then

hip extension, while the bac s=uat involves

simultaneous nee and hip extension. his means that

the deadlift liel involves meaningful length changes

in the hamstrings muscle, while the bac s=uat does

not, which probabl contributes to its abilit to

develop this muscle group. nlie the bac s=uat,

there have been few biomechanics studies

investigating the exercise techni=ue variables in the

deadlift that mae a difference to the effect of the

exercise on the woring musculature. 1onse=uentl,

the effects of load and depth are largel unnown.

/owever, a small number of investigators have

explored the differences between sumo and

conventional deadlifts. In general, such studies have

found more similarities than differences. /owever, the

sumo deadlift appears to involve greater stimulus for

the =uadriceps and tibialis anterior while the

conventional deadlift appears to involve greater calf

muscle stimulus. Additionall, the conventional deadlift

ma involve a greater amount of wor done #because

of the larger difference travelled' while the sumo

deadlift ma involve lower lumbar spinal loads

because the torso is less hori9ontall-inclined. In

addition, researchers have found that the exact

position of the sticing region in the deadlift does not

differ largel between the sumo and conventionaldeadlifts but does differ greatl between individuals.

;rograming for woring through the sticing region in

the deadlift ma thus re=uire precise consideration of

an athleteTs individual weanesses in order to move

forwards.

OBJC!"#$ o compare the hexagonal barbell

deadlift and straight barbell deadlift, in respect of the

absolute load lifted, the electromograph #E0'

amplitudes recorded in the =uadriceps #vastus

lateralis', hamstrings #biceps femoris', and low bac

#erector spinae' muscles #b surface electrodes' as

well as pea force and pea power #as measured

using a force plate', and pea velocit #as measuredwith a linear velocit transducer'.

%O%&'(!"O)$ $% males, aged $7.7 5 $.& ears, with

resistance training experience, and the abilit to lift

&.4 times bodweight.

")!*#)!"O)$ All sub<ects lifted the straight bar

and the hexagonal bar deadlift for 7 repetitions each

with 24* and )4* of &+ on separate occasions,

while the researchers too measurements.

What happened?

+omparison of load, force, power, and velocity

nlie previous studies, these researchers found nosignificant difference in &+ between the straight and

hexagonal barbell deadlifts #&)&.6 5 $:.7 vs. &)&.& 5

$:.2g'. /owever, the found that the hexagonal

barbell deadlift displaed significantl greater pea

force #$,447 5 7:$ vs. $,4&% 5 724>', pea power

#&,):& 5 64$ vs. &,26% 5 72$W', and pea velocit

#%.)& 5 %.&: vs. %.:7 5 %.&6mFs' compared to the

straight barbell deadlift values.

+omparison of EM! amplitudes

he researchers reported significantl greater E0

amplitudes in the vastus lateralis for the hexagonal

barbell compared to the straight barbell deadlift, while

the straight barbell deadlift displaed significantl

greater E0 amplitudes in the bicep femoris and theerector spinae, compared to the hexagonal barbell

deadlift.


he researchers concluded that using the hexagonal

and straight barbell deadlifts leads to different

patterns of muscle activation, and that the hexagonal

barbell ma be more effective at developing maximal

force, power, and velocit, despite similar &+ values.

'imitations

he stud was limited as it was unclear wh the

hexagonal and straight barbell deadlifts produced

similar &+ values, when previous research has found

that the hexagonal barbell allowed a greater load to

be used. ;erhaps the sub<ects in this stud were more

familiar with the straight barbell than with the

hexagonal barbell.


8/18/2019 Scr Mar 2016 PDF


(n electromyographic and force plate analysis of the

deadlift performed with and without chains, #y Nijem,

+o#urn, &rown, ynn, 3 +iccone, in 'he Journal of

%trength 3 +onditioning 4esearch 5/.7"

Background

he deadlift is an exercise performed b lifting abarbell resting on the ground. It is a common exercise

for developing lower bod strength and si9e for both

athletes and bodbuilders, as well as being contested

as part of the three lifts in powerlifting. or a detailed

introduction to the deadlift, see the earlier stud

review.

OBJC!"#$ o compare the conventional, straight

barbell deadlift without chains with the same stle of

deadlift but performed with chains, in respect of the

electromograph #E0' amplitudes recorded in the

=uadriceps #vastus lateralis', gluteus maximus, and

low bac #erector spinae' muscles #b surface

electrodes' as well as pea force and pea rate of

force development #+D' #as measured using a forceplate'.

%O%&'(!"O)$ &7 males, aged $6.% 5 $.& ears, with

resistance training experience and &+ deadlift of

&:2.$ 5 $%.4g.

")!*#)!"O)$ All sub<ects first identified their

&+ convention, straight barbell deadlift without

chains. hen the performed both deadlifts with and

without chains for 7 repetitions with )4* of this &+

while the researchers too measurements. When

performed with chains, the chains accounted for $%*

of the )4* &+ load, matched at the top of the lift.

What happened?

+omparison of force and 4@8

he researchers found that the deadlifts performed

with chains involved significantl reduced force but

onl non-significantl reduced +D. his is liel

because of the lower load used over the initial part of

the movement when using chains, as the loads were

matched at the top of the lift.


he researchers found that onl the gluteus maximus

differed in respect of the E0 amplitude between the

two lifts, being greater without chains than when

using chains. his ma be related to the greater

average force produced during the movement.


he researchers concluded that the use of chain

resistance with deadlifts alters muscle activation and

force characteristics of the deadlift, particularl in

respect of the gluteus maximus.

'imitations

he stud was limited as the two deadlift conditions

were not matched b relative load, but rather b

absolute load at the top of the movement. herefore,

the E0 results are not directl comparable for the

purposes of matching effort levels.


8/18/2019 Scr Mar 2016 PDF


Interaction #etween leg muscle performance and

sprint acceleration kinematics, #y ockie, Jalilvand

+allaghan, Jeffriess, 3 Murphy, in Journal of *uman

<inetics 5/.6 "

Background

"print running is a e athletic =ualit that iscontested in its own right in trac and field, as well as

being critical for success in man team sports, such as

soccer, rugb, and both Australian +ules and American

ootball. 1onse=uentl, man researchers have

performed extensive wor into sprint running, both

overall and in respect of certain specific aspects,

including inematics #<oint angles' inetics #forces and

moments', stiffness, electromographic #E0'

activit, and the transfer of training to sprint running.

As a result, there is a large bod of nowledge in

respect of the features that are characteristic of elite

sprinters and also of the training methods that ma

lead to best results. "print running performance is

determined b the combination of stride length and

stride fre=uenc. 3bservational research indicates that

some athletes rel on stride length for increased

speed while others rel more on stride fre=uenc for

increased speed. Analsis of biomechanics suggests

that for improving stride length, hopping, bounding

and stepping drills ma be able to develop different

aspects of force production during the sprint running

gait ccle. Analsis of experimental trials suggests

that sprint training, resistance training, plometrics

and resisted sprint training all produce significant

improvements in stride length. he effectiveness of

plometrics ma be related to observations that the

storage of elastic energ is important for sprint

running performance. Indeed, researchers have found

that this elastic energ storage becomes more

important with increasing sprinting speed. his

indicates that drop <umps and other vertical

plometric exercises might be among the most

effective training tools. Indeed, since biomechanical

analsis suggests that the main role of the nee

extensors is one of shoc absorption and increased

<oint stiffness upon ground contact, this further

supports a role for reactive plometric training that

stresses this muscle group, such as drop <umps.

+elated to this idea are the results of musculoseletal

modeling research, which has reported that the

limiting factor for sprint running performance is

muscle contraction velocit. his suggests that training

rate of force development for the e running musclesma be the single most important factor in developing

sprint running performance. his probabl re=uires a

mix of training involving low loads with high velocities

#which can be achieved using plometrics' and high

loads with low velocities. or improving stride

fre=uenc, both experimental trials and biomechanical

analsis indicate that combined heav and explosive

training along with overspeed running, using either a

downhill slope or towing are all effective.

OBJC!"#$ o identif relationships between &%m

sprint running time #as measured b a velocimeter

comprising an electronic stopwatch attached to a

nlon thread', stride parameters #stride length and

fre=uenc, and ground contact and flight times', and

leg muscle performance #strength, hori9ontal <ump

distance, vertical <ump height, and vertical stiffness'.

%O%&'(!"O)$ $) field sports athletes #from rugb

union, rugb league, Australian football or soccer',

aged $$.72 5 $.)7 ears.

")!*#)!"O)$ All sub<ects completed timed &%m

sprints that were filmed so that stride parameters

could be measured for the % ( 4m, 4 ( &%m, and % (

&%m intervals. In addition, all sub<ects performed a

7+ bac s=uat, a countermovement <ump #1K', a

4-bound test #4B', a 6%cm drop <ump, for the

measurement of the reactive strength index #+"I',

and both bilateral and unilateral hopping for the

calculation of leg stiffness.

What happened?

4elationships with sprint running performance

he onl measurements to be related to sprint running

abilit over an of % ( 4m, 4 ( &%m, or % ( &%m were

1K height #r L %.6% ( %.46, over all 7 time periods'

and 4B distance #r L %.78 ( %.6:, over 4 ( &%m and

% ( &%m onl' and 4B distance relative to bod mass

#r L %.67, over 4 ( &%m onl'.

4elationships with stride parameters

he onl measurement to be related to either stride

length or stride fre=uenc over an of % ( 4m, 4 (

&%m, or % ( &%m was 7+ bac s=uat relative to bod

mass #r L %.7) over % ( &%m onl'. he onl

measurements to be related to either flight time orground contact time over an of % ( 4m, 4 ( &%m, or

% ( &%m were 7+ bac s=uat and 7+ bac s=uat

relative to bod mass #r L %.62 ( %.4& for flight time

over % ( 4m onl'.


he researchers concluded that the best predictors of

sprint running speed over short distances in this

population of field sport athletes were vertical <ump

height and hori9ontal <ump distance. In contrast,

stiffness was not associated with sprint running abilit.

'imitations

he stud was limited as it was an acute correlation

analsis, and altering these parameters ma not lead

to improvements in sprinting abilit.


http://www.degruyter.com/view/j/hukin.2015.49.issue-1/hukin-2015-0109/hukin-2015-0109.xml

http://www.degruyter.com/view/j/hukin.2015.49.issue-1/hukin-2015-0109/hukin-2015-0109.xml

8/18/2019 Scr Mar 2016 PDF


(nkle position during the Nordic curl does not affect

muscle activity of the #iceps femoris and medial

gastrocnemius, #y +omfort, 4egan, *errington,

'homas, McMahon 3 Jones, in Journal of %port

4eha#ilitation 5/.7"

Backgroundhe >ordic hamstring curl is the primar exercise used

for performing eccentric training of the hamstring

musculature during long-term trials investigating

hamstring strain in<ur prevention, although a range

of others have also been developed that ma also be

suitable. Additionall, it is commonl recommended as

the primar exercise to perform in order to prevent

and rehabilitate hamstring strain in<ur. his is

important, as few other conservative treatments have

an support. Despite this common advice, the

ma<orit of elite soccer teams fail to use the >ordic

hamstring curl in either prevention or rehabilitation

programs, which ma explain the continued high

incidence of both novel and recurrent hamstring strain

in<ur. he reasons for wh soccer teams have failed

to adopt the exercise are unclear, but ma relate to

the discomfort of the exercise, as it often leads to

muscle soreness. Exploring the electromograph

#E0' amplitude of the hamstrings during the >ordic

hamstring curl, some researchers have found that

E0 amplitude of the hamstrings is higher when the

nee is extended than when the nee was flexed,

indicating that the exercise trains the hamstrings at

longer muscle lengths. /owever, other studies have

not reported an effect of <oint angle on E0

amplitude during the >ordic hamstring curl. herefore,

whether the exercise does displa a tendenc to

activate the hamstrings at longer or shorter muscle

lengths remains unclear. 1omparing the medial and

lateral hamstrings, some investigations have found

that the >ordic hamstring curl produced preferentiall

higher E0 amplitudes in either the semitendinosus or

biceps #short head', but others have not reported an

preferential activation. herefore, whether there is an

difference between medial and lateral hamstrings E0

amplitudes in the >ordic hamstring curl #and whether

it in fact matters' remains unclear. Exploring multiple

sets of the >ordic hamstring curl exercise, a recent

stud reported that a single set of 4 repetitions led to

substantial reductions in pea eccentric nee flexion

moments during the exercise, with further reductions

in subse=uent sets, impling that performing the

>ordic hamstring curl prior to practice or otherexercise might not be advisable. Even so, training

under fatigued conditions ma have benefits if

carefull managed. An older, long-term training stud

using the >ordic hamstring curl either before or after

practice observed that the timing of the exercise led to

different effects. raining before practice led to greater

strength gains being displaed when measured before

a simulated game but training after practice led to

greater gains in nee flexion strength being displaed

when measured after the simulated game. his

indicates that performing hamstrings training under

conditions of fatigue ma benefit the demonstration of

hamstrings strength under fatigued conditions.

OBJC!"#$ o assess the effect of anle dorsiflexion

during a >ordic hamstring curl on E0 amplitudes of

the biceps femoris and medial gastrocnemius muscles

#as measured b surface electrodes'.

%O%&'(!"O)$ &4 male collegiate athletes, aged $$.2

5 $.& ears.

")!*#)!"O)$ All sub<ects performed $ sets of 7

repetitions of both variations of >ordic hamstring

curls, while the researchers too measurements.

What happened?

Effect of ankle position

he researchers found that when comparing the

plantar-flexed and dorsiflexed anle positions, there

was no significant difference in the normali9ed E0

amplitudes of the biceps femoris #&$6.4 5 2.$* vs.

&$).& 5 4.%*' or of the medial gastrocnemius #)$.&

5 7.8* vs. )7.4 5 6.)*'. he noted that the levels

of activation were greater than maximal for the

hamstrings and nearl maximal for the gastrocnemiusmuscles.


he researchers concluded that the anle position

does not affect hamstrings or medial gastrocnemius

muscle activation during >ordic curls.

'imitations

he stud was limited, insofar as the length of

gastrocnemius at which the muscle is most active is

liel greater in the dorsiflexed variation of the

exercise, which ma et lead to different training

effects despite the similar E0 amplitudes measured.

/owever, the length of the gastrocnemius muscle ineach case was not measured.


8/18/2019 Scr Mar 2016 PDF


+ontri#ution of elastic tissues to the mechanics and

energetics of muscle function during movement, #y

4o#erts, in Journal of Experimental &iology 5/.7 "

Background

he sliding filament theor predicts that when

sarcomeres contract isometricall, the maximumpossible force should be proportional to the number of

overlapping cross-bridges. /owever, it has been

observed that isometric force is greater than expected

when contractions follow eccentric contractions than

when the follow concentric contractions at the same

muscle length. his phenomenon is nown as residual

force enhancement and cannot be explained using the

classical sliding filament theor. ;revious researchers

have found that the propert of residual force

enhancement increases with increased magnitude of

stretch and increases even more as the muscle is

stretched on the descending limb of the length-tension

relationship, which suggests that a passive mechanism

is responsible for its behavior. itin is a spring-lie

protein and is the primar contributor to passive force

when sarcomeres are stretched beond a certain

resting length. It is therefore thought to be a e

contributor to the propert of residual force

enhancement. /owever, it appears to be a multi-

functional protein and also contributes to other muscle

functions, including centering of the thic filament,

sarcomere stabilit, and a number of signaling events.

itin can be divided into an A-band and an I-band

region. +esearchers have concluded that the I-band is

extensible and is made up of a proximal Ig and ;EJR

spring, which appear to be the primar contributors to

the production of tension during stretch. "ome

researchers have proposed that the sliding filament

theor can be modified to include the behavior of titin

and simultaneousl explain the spring-lie behavior of

sarcomeres and the propert of residual force

enhancement. It has been noted that calcium causes

titin to bind to actin while actin and mosin are

forming a cross-bridge. 1ross-bridge formation pulls

and twists the actin #the action is not <ust a slide as

the sliding filament model previousl proposed since

there is a twisting component'. When the actin is

twisted, since titin is bound to the actin, titin goes

along for the ride. he stretching and winding of titin

creates stored elastic energ which leads to

subse=uent #or indeed residual' force enhancement.

"ome researchers have noted that titin ma in fact

explain wh seletal and cardiac muscle have suchdifferent length-tension propertiesG cardiac muscle is

never stretched when active so it doesnTt receive the

same spring-lie benefits. itin ma also explain wh

activated muscles have enhanced force compared to

passive muscles at identical lengthsG active muscles

store elastic energ through stretched titin, and the

greater the stretch, the greater the subse=uent force

enhancement. inall, titin also explains wh eccentric

exercise produces more tension at the same length

compared to concentric exerciseG because of the

utili9ation of stored energ in the titin molecule.

OBJC!"#$ o perform a narrative review of how

elastic elements #inside both muscles and tendons'

influence muscle function during locomotion.

What happened?

Interactions #etween muscles and tendons

he reviewer explains how the interactions betweenmuscles and tendons in-series influence the storage

and subse=uent release of elastic energ in gait or

other bod movements. hese interactions allow the

timing of muscle wor relative to the timing of the

movement to be altered, which is e for enhancing

performance. or example, when <umping, if there

was no interaction between the tendon and muscle,

then the muscle would need to develop force ver

=uicl, and thereb produce little force, and the <ump

would be fairl low in height. In realit, b contracting

the muscles and lengthening the tendons prior to the

<oints moving, the muscle is able to contract more

slowl, produce more force, and store this muscle

wor before an movement happens, which is then

released in the <ump. he reviewer notes that this

concept is termed power amplification. A ver similar

process occurs in landing, where the tendon absorbs

the initial change in length while the <oint moves

=uicl, as the muscle produces force but remains a

constant length. Afterwards, when the <oint motion

has ended, the tendon recoils at a slower speed and

stretches the active muscle, doing wor on it. he

reviewer notes that this is called power attenuation.

Elastic energy storage in muscles

In addition to the interactions between muscles and

tendons, the reviewer explains that muscles have their

own inherent elastic properties. hese arise from

various different structures, including the actual cross-bridges themselves, the individual actin, mosin and

titin filaments, and collagen fibers within the extra-

cellular matrix that surrounds the muscle fibers. he

titin filament is believed to be the most important

filament, undergoing ver large elastic deformations in

comparison with the actin and mosin filaments. Even

so, it is liel that the extracellular matrix produces a

greater overall contribution to elastic energ storage

in muscles. 1omparisons of the stiffness of isolated

muscle fibers #containing little or no connective tissue'

and bundles of fibers #which do contain connective

tissue' indicate that the extracellular matrix probabl

provides the ma<orit of the passive force in muscles.

What did the researcher conclude?

he researchers concluded that elastic tissues affect

muscle function ver maredl. he amplif muscle

power b storing muscle wor slowl and releasing it

rapidl. he absorb external impacts b storing

impact energ and releasing it more slowl to stretch

muscle activel.

'imitations

he stud was limited as it was a narrative review,

which ma not reflect the views of all researchers

woring in this field.




8/18/2019 Scr Mar 2016 PDF


'he increase in non$cross$#ridge forces after stretch

of activated striated muscle is related to titin

isoforms, #y +ornachione, eite, &agni, 3 4assier, in

(merican Journal of Physiology 5/.7 "

Background

itin is a spring-lie protein and is the primarcontributor to passive force when sarcomeres are

stretched beond a certain resting length. It is

therefore thought to be a e contributor to the

propert of residual force enhancement. /owever, it

appears to be a multi-functional protein and also

contributes to other muscle functions, including

centering of the thic filament, sarcomere stabilit,

and a number of signaling events. or a detailed

introduction to titin, see the earlier stud review.

OBJC!"#$ o measure the static tension of isolated

muscle fibers with different titin isoforms #b taing

muscle fibers from the psoas, soleus, and ventricle

muscles of the rabbit, which each contain different

titin isoforms'. "tatic tension is the term given to the

increase in force observed during passive stretch of

isolated muscle fibers exposed to solutions with high

concentrations of 1a$ ions, which ma be because of an increase in titin stiffness that occurs in response to

this exposure.

")!*#)!"O)$ he researchers measured the

static tension of the mofibrils at stretches of different

si9es, with the individual sarcomere lengths varing

between &.87 ( 7.7:Sm for the psoas, between $.2) (

6.$&Sm for the soleus, and between &.4& ( $.)2Sm

for the ventricle.

What happened?

8ifferences in static tension

he researchers found that the relative increase in

force after stretch differed between the psoas, soleus,and ventricle muscles. orce increased significantl in

the psoas and soleus muscles, but not in the ventricle

muscle. orce was increased b 6.% 5 %.$ n>FSm$ in

the ventricle muscle fibers, b ).& 5 %.7 n>FSm$ in

the soleus muscle fibers, and b &7.) 5 &.$ n>Fm$ in

the psoas muscle fibers. hese changes in force

production were each significantl different from one

another.


he researchers concluded that the changes in the

static tension that occur in response to the addition of

solutions of 1a$ ions to isolated muscle fibers is

different between muscle fibers containing differenttitin isoforms.

'imitations

he stud was limited insofar as it was performed in

rabbit muscle fibers and different results might be

found in the muscles of other species. In addition, it is

unclear what the impact of this discover might have

on an understanding of muscle mechanics.




8/18/2019 Scr Mar 2016 PDF


Eccentric contraction unraveling mechanisms of

force enhancement and energy conservation, #y

Nishikawa, in 'he Journal of Experimental &iology

5/.7 "

Background

+esistance training improves man athletic =ualities,including muscular strength, si9e, power, <umping and

sprint running performance. It is also important for

improving function and reducing sarcopenia in elderl

people. he exact wa to structure resistance training

programs is unclear. here are man training variables

that can be manipulated, including relative load,

volume, fre=uenc, proximit to muscular failure, rest

period duration, muscle action and repetition speed.

uscle action is varied when researchers compare

eccentric-onl, concentric-onl or combined stretch-

shortening muscle actions. hese comparisons can be

made using isoinetic or isoinertial resistance tpes.

Isoinetic resistance maes it easier to control certain

variables but it maes the results less relevant, as few

trainees mae use of this modalit. here are some

grounds for hpothesi9ing that eccentric-onl training

ma be beneficial for muscular adaptations #both

strength and si9e'. Eccentric-onl muscle actions ma

involve a lower energ cost for the same amount of

mechanical tension. hus, lifters are able to perform a

greater volume of wor while taxing their wor

capacit to the same degree. Additionall, eccentric-

onl muscle actions enable athletes to lift a larger

amount of weight than during concentric-onl or

stretch-shortening ccle muscle actions with the same

percentage of &+. his ma lead to greater

mechanical tension for the same relative load and

greater adaptations. inall, eccentric-onl muscle

actions ma cause earlier activation of the higher

threshold motor units which are capable of displaing

greater amounts of force. hus, there appears to be

some biological plausibilit for using eccentric-onl

muscle actions to improve strength. Indeed, when

considering isoinertial training studies onl comparing

either eccentric-onl or concentric-onl muscle

actions, there is a trend to suggest that training with

eccentric-onl muscle actions leads to greater

increases in eccentric strength #isoinertial or

isoinetic' than training with concentric-onl muscle

actions. /owever, for isoinertial training involving

either eccentric-onl or concentric-onl muscle

actions, there is a trend that training with concentric-

onl muscle actions leads to greater increases inisometric strength than training involving eccentric-

onl muscle actions. he literature is conflicting

regarding whether training with eccentric-onl or

concentric-onl muscle actions leads to different

improvements in isoinertial #eccentric-onl or

concentric-onl' or isoinetic #eccentric-onl or

concentric-onl' or concentric-onl #isoinertial or

isoinetic' strength. +egarding hpertroph following

training using isoinertial methods, the literature is

conflicting and it is currentl unclear whether using

eccentric-onl or concentric-onl training is superior.

OBJC!"#$ o do a narrative review of the literature

exploring the finding that isometric force produced b

a muscle after it has been activel stretched is greater

than the isometric force produced at the stretched

length, which is called residual force enhancement

#+E', noting that there are 7 possible explanationsG

#&' greater cross-bridge force, sarcomere non-

uniformit, and engagement of structural elements#lie titin' at the point of muscle activation.

What happened?

!reater cross$#ridge force

he greater cross-bridge force explanation suggests

that the force exerted b the actin-mosin binding is

simpl greater after active stretch, perhaps because of

some chemical alteration. he reviewer explains that

this idea is hard to assess, as direct measurements

are impossible. In addition, indirect measurements

have found contradictor results, and the si9e and

duration of +E impl that this mechanism is not reall

that plausible.

%arcomere non$uniformity

he sarcomere non-uniformit explanation suggests

that the force is greater after active stretch because

some sarcomeres are lengthened and operate on the

passive length-tension curve, while others do not. his

would predict that sarcomere length would be more

variable after stretch than in isometric contractions,

that +E would onl happened at the plateau and on

the passive length-tension curve, and that the si9e of

the enhanced force would never be greater than the

maximum isometric force. /owever, the reviewer

notes that research has identified that such features

have not been found, which refutes the basis of this

explanation for +E.

Engagement of structural elements

In the engagement of structural elements explanation,

it is suggested that parts of the sarcomere increase in

stiffness when the muscle is activated, which then

contribute to the +E effect. "ince a part #but not all'

of the +E effect is maintained even after the muscle

activation ends, it is assumed that there must be both

chemical and structural elements to the effect. his

effect is liel produced b the winding filament

mechanism, whereb titin interacts with the cross-

bridges in active sarcomeres.


he researcher concluded that the +E effect during

eccentric contractions results from the engagement of

titin upon muscle activation, and this effect persists

after the loss of muscle activation.

'imitations







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Neural control of lengthening contractions, #y

8uchateau 3 Enoka, in 'he Journal of Experimental

&iology 5/.7 "

Background

here are some grounds for hpothesi9ing that

eccentric-onl training ma be beneficial for muscularadaptations #both strength and si9e'. or a detailed

introduction to eccentric-onl training, see the earlier

stud review.

OBJC!"#$ o provide a narrative review of the

neural mechanisms b which lengthening or eccentric

muscle actions differ from those of shortening or

concentric muscle actions.

What happened?

Eccentric and concentric muscle actionshe reviewers explain that there are two important

biomechanical factors that differ between eccentric

and concentric muscle actions. irstl, because of the

passive elements contributing more during eccentric

muscle actions, the overall force-generating capacit

of the muscle is necessaril greater. herefore, when

using the same absolute load as a concentric muscle

action, the relative load will be lower. his means that

lower muscle activation #such as is measured using

electromograph E0C' will be recorded, unless the

load or velocit is standardi9ed. "econdl, when using

constant loads #such as a barbell', muscle force is less

when using an eccentric muscle action than for a

concentric muscle action with the same absolute load,

as although both muscle actions involve overcoming

the weight of the barbell against gravit, onl the

concentric muscle action acts against inertia. his

again means that comparing concentric and eccentric

muscle actions with the same absolute load is not ver

useful, as the effective forces are ver different.

Neural control of eccentric muscle actions

he reviewers noted that older studies have found

conflicting indications that eccentric muscle actions

ma displa different motor recruitment patterns from

concentric muscle actions. "uch findings have led

some researchers to propose that eccentric muscle

actions preferentiall recruit higher threshold motor

units, and potentiall alter the si9e principle of motorunit recruitment. /owever, the reviewers note that on

balance, this does not appear to be the case, and in

fact the recruitment order of motor units appears to

be similar between concentric and eccentric muscle

actions, and is consistent with the si9e principle.

+ather, the reduction in E0 amplitude observed in

eccentric muscle actions appears to be the result of

reduced spinal and corticospinal excitabilit compared

to concentric and isometric muscle actions, which

leads to a reduction in the motor unit firing fre=uenc.


he researchers concluded that contrar to popular

belief, there is no difference in motor unit recruitmentpatterns between concentric and eccentric muscle

actions, and eccentric training therefore does not

preferentiall recruit high threshold motor units.

'imitations







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Muscle force loss and soreness su#seBuent to maximal

eccentric contractions depend on the amount of

fascicle strain in vivo, #y !uilhem, 8oguet, *auraix,

acourpaille, Ju#eau, Norde2 3 8orel, in (cta

Physiologica 5/.7 "

Backgroundhere are some grounds for hpothesi9ing that

eccentric-onl training ma be beneficial for muscular

adaptations #both strength and si9e', and that it ma

lead to greater muscle damage post-worout. or a

more detailed introduction to eccentric-onl training,

see the earlier stud review.

OBJC!"#$ o identif whether there are an

relationships between muscle(tendon unit behaviors

during maximal eccentric muscle actions #as recorded

using ultrasonograph' and the extent of subse=uent

muscle damage #as measured b reference to the

change in maximal voluntar isometric contraction

#JI1' plantar-flexor tor=ue, alterations in medial

gastrocnemius E0 amplitude, perceived delaedonset muscular soreness #D3"', and muscle shear

modulus at 6) hours post-worout'.

%O%&'(!"O)$ &: sub<ects #8 males and ) females',

aged $4.% 5 7.: ears.

")!*#)!"O)$ All sub<ects performed &% sets of

7% maximal eccentric plantar-flexor muscle actions at

64 degreesFs, while the researchers measured the

length of the muscle(tendon unit, the length of the

muscle fascicles, and the lengths of the tendinous

tissues of the gastrocnemius medialis.

What happened?

Muscle$tendon unit #ehavior

he researchers reported that the muscle(tendon unit,

muscle fascicles and tendinous tissues were stretched

up to 6.66 5 %.77 cm, $.7& 5 %.26 cm and &.8$ 5

%.2& cm respectivel. uscle fascicles and tendinous

tissues were lengthened at average velocities of &.26

5 %.6: cmFs and &.66 5 %.68cmFs and pea velocities

of $.$8 5 %.:6cmFs and 6.$2 5 &.67cmFs respectivel.

he contribution of tendinous tissues to the total

muscle(tendon lengthening was higher than the

contribution of the fascicles between &) and -$%

degrees, while the opposite was found between -72

and -6$ degrees #negative angles representing greater

dorsiflexion'. /owever, the researchers also noted that

there was significant inter-individual variabilit in both

muscle(tendon unit and muscle fascicle behavior.

Exercise$induced muscle damage

he researchers found that exercise-induced muscle

damage was observed at 6)-hours post-worout, as

JI1 tor=ue significantl reduced b &4.2 5 ).7* and

D3" increased significantl to 66 5 $)mm, although

there was no change in shear modulus values.

4elationships

he researchers reported that the amount of fascicle

stretch length, the lengthening amplitude, and the

negative fascicle wor beond slac length were each

significantl correlated with the reduction in force at

6) hours post-worout #r L %.4&, %.6: and %.2),

respectivel'.


he researchers concluded that it is the magnitude of

the stretch applied to active muscle fascicles combined

with high levels of force produced at long lengths in

maximal eccentric muscle actions that determines the

extent of subse=uent muscle damage.

'imitations

he stud was limited insofar as the findings were

onl reported in one muscle.




8/18/2019 Scr Mar 2016 PDF


(rchitectural adaptations of muscle to training and

injury a narrative review outlining the contri#utions

#y fascicle length, pennation angle and muscle

thickness, #y 'immins, %hield, :illiams, oren2en, 3

0par, in &ritish Journal of %ports Medicine 5/.7 "

Backgrounduscle architecture is the organi9ation of the muscle

fibers within the muscle with respect to the line of

pull. he line of pull is the line drawn through the

origin and the insertion of the muscle. uscle

architecture is one of the least well-researched

sub<ects when it comes to how muscles wor. Despite

this, most researchers regard it as the single most

important factor when it comes to determining a

muscleTs function, force production capacit and

contraction velocit. uscle architecture comprises

three main aspectsG fiber or fascicle length, pennation

angle, and phsiological cross-sectional area #;1"A'.

ogether, these three factors can be used to describe

an given muscle or muscle compartment. ascicle

length is the average length of the muscle fascicles

within the muscle. It is often used instead of the more

correct measurement of muscle fiber length because it

is far easier to calculate. 1hanges in fascicle length

have a mared effect on the abilit of a muscle to

produce force. his is because longer fibers contract at

higher velocities than shorter fibers. @onger fascicles

contract more =uicl than shorter fascicles because

all of the sarcomeres in a single muscle fiber contract

at the same time. "ince sarcomeres in a single muscle

fiber are arranged in series, this produces a greater

relative reduction in si9e from the same starting

length. Indeed, researchers have observed that

muscle fascicle length tends to be longer in elite &%%m

sprinters than long-distance runners as well as in less-

well-trained sprinters. uscle fiber length, or more

accuratel, normali9ed fiber length, is the length of the

muscle after correcting for the average length of the

sarcomeres within it. his normali9ation process is

used so that muscles can be compared even when

the are stretched or contracted. An increase in

normali9ed fiber length therefore tells us that the

number of sarcomeres in series has increased #b a

process called sarcomerogenesis'. ;ennation angle is

the angle of the muscle fibers within the muscle with

respect to the angle of pull. ost muscles contain

fibers that are at an angle of between % ( 7% degrees.

;ennation angle is the aspect of muscle architecture

that changes most with training. As the pennationangle increases, more muscle fibers are able to fit into

the same anatomical cross-sectional area #A1"A',

although the ;1"A in fact increases, because this is

measured at right angles to the line of pull. As

pennation angle decreases the force that each muscle

fiber can produce, increasing pennation angle is

therefore a trade-off between increasing the number

of muscle fibers but reducing the mechanical

advantage. It should therefore be clear that ;1"A is

not =uite the same as A1"A. A1"A is measured at

right angles to the angle of pull whereas ;1"A is

measured at right angles to the pennation angle.

OBJC!"#$ o perform a narrative review to explore

the inter-relationships between muscle architecture

and muscle strain in<ur.

What happened?

Effects of fascicle length on muscle function

uscle fascicles are made up of sarcomeres in series,with each sarcomere being roughl the same length in

all muscles. 1onse=uentl, where one muscle fascicle

length is longer than another, it must necessaril

contain more sarcomeres. When a muscle fascicle

contracts, all of the sarcomeres contract at the same

time. his means that long muscle fascicles reduce in

length to a greater extent than shorter muscle

fascicles, and do so much faster. 1onse=uentl, muscle

fascicle length strongl influences the force(velocit

relationship in muscles, and potentiall therefore has

a ver substantial influence on muscle function. he

reviewers reported that in vivo animal studies have

confirmed that different muscle heads can indeed

have vastl differing maximal shortening velocities

from one another, because of their different fascicle

lengths. he further observe that since it has been

found that previousl strained muscle possesses

shorter fascicles in comparison to unin<ured muscles,

this could mean that in<ured muscle displas reduced

maximal shortening velocities.

Effects of muscle strain injury on architecture

uscle fascicles are made up of sarcomeres in series,

and each sarcomere displas a curve of length vs.

tension, where it can produce little force at ver short

lengths #because there is little overlap between cross-

bridges', high force at moderate lengths, reduced

force at longer lengths, and then ver high force at

ver long lengths #because of increasing involvementfrom passive structures'. his pattern is repeated

along the length of the muscle fascicle, producing an

overall length-tension relationship for the muscle,

which can be detected indirectl using a tor=ue-<oint

angle curve measured using a dnamometer. he

researchers noted that some studies have found a

shift in the angle of pea tor=ue of the nee flexors

towards smaller angles and therefore shorter muscle

lengths in individuals with a previousl in<ured

hamstring, which ma therefore reflect a reduction in

the number of sarcomeres in-series within the muscle

fascicle.

What did the researchers conclude?he researchers concluded that there are indications

that previousl-in<ured muscles have significantl

shorter fascicle lengths than unin<ured muscles, and

that this could impact on muscle function both through

the force-velocit and length-tension relationships.

'imitations

he stud was a narrative review and therefore was

based upon the opinions of the authors, which ma

not reflect the views of all researchers woring in the

field.


http://bjsm.bmj.com/content/early/2016/01/27/bjsports-2015-094881.short

http://bjsm.bmj.com/content/early/2016/01/27/bjsports-2015-094881.short

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Effect of neck flexion restriction on sternocleido$

mastoid and a#dominal muscle activity during curl$up

exercises, #y ee, Moon, 3 *ong, in Journal of

Physical 'herapy %cience 5/.7 "

Background

Electromograph #E0' is a commonl-used methodthat helps researchers understand how strongl a

muscle is contracting. E0 is performed using an

electromograph in order to produce an output nown

as an electromogram. An electromograph detects

electrophsiological activation of a muscle during the

production of mechanical force. E0 is an important

method as it is not possible with current technolog to

measure forces inside a muscle. usculoseletal

modeling can provide an estimate of these forces but

such values are based upon a variet of assumptions

and are indirect and not direct measurements.

easuring E0 activit using an electromograph

involves placing electrodes either on or in a muscle.

Electrodes can be placed either upon the sin #surface

E0' or directl into the muscle itself #fine wire E0'.

While fine wire E0 is thought to provide a more

accurate picture of the E0 activit in a ver specific

part of a muscle, it is invasive and so surface E0 is

more commonl used. "ignals from surface E0

electrodes are less reliable than signals from fine wire

electrodes because the can experience interference

from neighboring muscles and the can slip or move

during muscle actions, particularl where concentric or

eccentric muscle actions are being performed #and not

isometric muscle actions'. he electrophsiological

signal detected b electrodes starts when a muscle

fiber or group of muscle fibers is activated b the

central nervous sstem #1>"' via a motor nerve. he

activation starts with the electrophsiological

depolari9ation cell membranes, leading to the release

of 1a$ ions within the muscle cells, and the

subse=uent activation of actinFmosin filaments to

produce a shortening of each sarcomere. hus, E0

amplitude and mechanical force are closel related.

"ince mechanical loading is thought to be the primar

driver for muscular hpertroph, it is therefore

unsurprising that exercises that displa high E0

amplitudes in certain muscle groups are thought to be

those that are most effective for developing those

parts of the bod. /owever, the interpretation of E0

amplitude is not a simple matter and the signal

re=uires processing and normali9ation before it can be

properl compared with other signals. >ormali9ation ismost commonl performed relative to the signal

recorded during a maximum voluntar isometric

contraction in a position thought to lead to the

greatest possible E0 activit of the muscle in

=uestion. "uch positions are not alwas nown for all

muscles, however. Additionall, normali9ation can also

be performed relative to a non-maximal, reference

contraction. Additionall, the nature of the E0

measurement taen can differ between studies,

depending on whether average E0 amplitude is

taen across the whole of a given muscle action, or

whether the pea E0 amplitude during a given

muscle action is recorded.

OBJC!"#$ o investigate the effect of nec flexion

restriction on sternocleidomastoid #"1' #a superficial

cervical flexor', rectus abdominis and external obli=ue

E0 amplitudes #using surface electrodes' in the

trun curl exercise.

%O%&'(!"O)$ &7 health male sub<ects, aged $7.:

5 %.6 ears.

")!*#)!"O)$ All sub<ects performed a traditional

trun curl exercise and a trun curl exercise in which

nec flexion was restricted. +estriction of nec flexion

was achieved b tactile cues using the sub<ectTs hand

to encourage adoption of the chin tuc position. he

trun curl was performed in supine with both arms

down b the sides, nees flexed to approximatel 8%

degrees and feet placed flat on the floor. he sub<ects

elevated their trun b lifting their head and shoulders

until the scapulae were lifted from the floor.

What happened?

Effects of neck flexion restrictionhe researchers observed significantl lower "1 E0

amplitude during the trun curl exercise with nec

flexion restriction compared to the traditional trun

curl exercise. In contrast, the found that the E0

amplitudes of the rectus abdominis and external

obli=ue muscles were significantl higher in the trun

curl exercise with nec flexion restriction compared to

the traditional trun curl exercise.


he researchers concluded that performing the trun

curl with nec flexion restriction b using tactile cues

to promote the chin tuc position is advantageous for

promoting lower cervical nec flexor muscle activationand higher abdominal muscle activation.

'imitations

he stud was limited insofar as it is unclear to what

extent similar results would be observed in other

populations, particularl those with low bac pain or

nec pain.


http://jlc.jst.go.jp/DN/JLC/20019979500

http://jlc.jst.go.jp/DN/JLC/20019979500

8/18/2019 Scr Mar 2016 PDF


Electromyographic activity and .64M load during

resistance exercises on sta#le and unsta#le surfaces,

#y (randa, Mancini, :erneck, Novaes, 8a %ilva$

!rigoletto, 3 9ianna, in Journal of Exercise Physiology

0nline 5/.7"

BackgroundInstabilit training has become a popular method for

simultaneousl developing the core musculature as

well as certain prime movers. Indeed, researchers

have found that when standard upper- or lower-bod

exercises are performed under unstable conditions,

this generall leads to increased core muscle activit,

as measured b electromograph #E0'. /owever,

acute studies exploring the prime movers in lower-

bod exercises have generall found that unstable

variations lead to lower E0 activit than their stable

e=uivalents. "imilar studies investigating the prime

movers during upper-bod exercises have found

slightl more conflicting results, with some studies

showing benefits of instabilit training, others showing

no benefit, and others showing a detrimental effect.

/owever, A recent long-term investigation found that

instabilit training with a range of exercises using a

suspension device was able to produce similar gains in

strength to a set of similar, stable exercises for the

upper-bod and for the lower-bod in previousl

untrained males. hus, it ma be the case that

instabilit training is similarl effective as traditional

resistance training for the upper- and lower-bod

prime movers in untrained sub<ects. Whether it is

capable of achieving similar gains in trained

individuals, however, is uncertain.

OBJC!"#$ o compare the E0 amplitudes #using

surface electrodes' and the &4+ load in bench press

and bac s=uat exercises performed either on a stable

surface or on an unstable surface. or the bench

press, the researchers measured the anterior deltoid

and pectoralis ma<or muscles. or the bac s=uat,

the measured the biceps femoris and vastus lateralis

muscles.

%O%&'(!"O)$ &8 health males, aged $6.24 5 7.6)

ears.

")!*#)!"O)$ All sub<ects performed the bench

press on either a bench or on a "wiss ball, and the

bac s=uat either on the ground or on two balance

diss.

What happened?

+omparison of .64M loads

he researchers reported that the absolute load value

for the bac s=uat &4+ load was significantl higher

in the stable condition than in the unstable condition#)7.8 5 &).2: vs. :%.7 5 &%.%:g'. /owever, there

was no significant difference in respect of the bench

press &4+ load between the stable and unstable

conditions #22.% 5 &%.&4 vs. 26.$ 5 ).27 g'.


In the bench press, the researchers observed no

significant differences in the E0 amplitudes of the

anterior deltoid or pectoralis ma<or between the stable

and unstable conditions. "imilarl, in the bac s=uat,

the researchers observed no significant differences in

the E0 amplitudes of the biceps femoris or vastus

lateralis between the stable and unstable conditions.


he researchers concluded that for the bac s=uat,

using an unstable surface allowed a lower absolute

load to be used, and et there was no difference in the

E0 amplitudes of the leg muscles. he concluded

that for the bench press, using an unstable surface

had no effect on either the load or the E0 amplitudes

of the prime movers.

'imitations

he stud was limited as it did not involve trained

sub<ects and different results might be observed in

individuals who were familiar with the exercises.


8/18/2019 Scr Mar 2016 PDF



-% ANATOM*) PH*SIOLO'*) AND NUTRITION


8/18/2019 Scr Mar 2016 PDF


'he effects of a high protein diet on indices of health

and #ody composition a crossover trial in resistance$

trained men, #y (ntonio, Eller#roek, %ilver, 9argas, 3

Peacock, in Journal of the International %ociety of

%ports Nutrition 5/.7 "

Backgroundhe global consumer maret for dietar supplements

in $%&& was estimated at UV7% billion. ;rotein

supplements are among the most popular items

purchased. ;rotein supplements are available in both

li=uid and solid forms, although the li=uid form is the

most common. Additionall, while various tpes of

protein are available, whe is the most commonl

used in commerciall-available supplement formulas.

;rotein supplements are primaril intended to increase

muscular strength and si9e when consumed in

combination with periods of resistance training, largel

b increasing total dail protein intae. +esearch

indicates that consuming a protein supplement ma

increase total protein intae but other dietar factors

ma be modifing factors, including whether

individuals are engaged in caloric restriction or not.

>evertheless, a substantial bod of acute research has

found that dietar protein consumption immediatel

post-resistance training exercise leads to an increase

in muscle protein snthesis and a reduction in muscle

protein breadown. Increases or decreases in

muscular si9e #hpertroph or atroph' are thought to

occur through a sustained imbalance between muscle

protein snthesis and muscle protein breadown.

"ince increases in muscle protein snthesis are

believed to be important contributors to long-term

gains in muscle mass, this is often taen as evidence

that protein supplementation can be used to enhance

gains in muscular strength and si9e. /owever, not all

long-term trials have supported this claim and we

should be cautious about drawing strong inferences

about hpertroph from the behavior of muscle

protein snthesis and the balance between muscle

protein snthesis and muscle protein breadown in

acute trials, as some studies have found no correlation

between these acute responses and long-term gains in

muscle mass. It is fortunate that meta-analses of

trials of resistance training programs of P2 wees

have reported that protein supplementation does lead

to superior gains in strength and si9e in both oung

and old adult sub<ects. ;rotein supplementation ma

be provided from several different sources and some

researchers have suggested that the use of eitherwhe, casein or essential amino acids ma lead to

different effects, most liel b altering the rate of

muscle protein snthesis or muscle protein breadown

post-exercise. Indeed, essential amino acids such as

the branched-chain amino acids #B1AA' can increase

muscle protein snthesis and reduce muscle protein

breadown. Additionall, the essential amino acid

leucine could be an important modulator insofar as it

seems to lead to an increase in the activit of

important signaling proteins.

OBJC!"#$ o assess the effects of an )-wee, high-

protein diet #7g per g of bodweight' in resistance-

trained males on a comprehensive metabolic panel

and blood lipids to assess health status #as measured

b taing blood samples' resistance training exercise

performance #as measured b &+ bench press, and

repetitions to failure with 2%* of bench press &+'

and bod composition #as assessed b whole boddensitometr using air displacement via the Bod ;od'

in oung males with resistance training experience.

%O%&'(!"O)$ &$ health, resistance-trained males,

aged $4.8 5 7.: ears, with a mean bodweight of

)4g and a mean &+ bench press of &$%g.

")!*#)!"O)$ he sub<ects performed their own

resistance training program but undertoo to consume

P7g per g of protein per da in one )-wee period,

and their customar amount of protein in another )-

wee period, for direct comparison.

What happened?

Effects on protein intake

During the normal and high protein phase of the

treatment period, the researchers reported that the

sub<ects consumed $.2 5 %.) and 7.7 5 %.) g per g

of bodweight per da of protein, respectivel. he

noted that the amount of protein in the high-protein

condition was significantl greater than in the normal-

protein condition. Even so, it is noteworth that the

sub<ects were alread consuming greater than the

recommended dail allowance #+DA' of protein for

their customar protein consumption.

Effects on #ody composition and health markers

he researchers identified no significant changes in

bod composition or marers of health between thetwo conditions. he examined the two individuals

with the highest recorded protein intaes #6.22g and

2.48g per g of bodweight per da!' and found no

adverse effects on renal function in either.


he researchers concluded that consuming a high

protein diet #$.2 ( 7.7g per g of bodweight per da'

over a 6-month period has no adverse effects on a

comprehensive metabolic panel and blood lipids

assessing health status, including renal and hepatic

function. he concluded that this stud demonstrates

that an increase in protein intae to P6 times the +DA

has no harmful effects.

'imitations

he stud was limited in that it was performed in

oung resistance-trained males who were alread

habituall consuming a high protein intae. Different

results might be observed in older individuals, or

those who are not accustomed to consuming such

high levels of protein.


http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4715299/


8/18/2019 Scr Mar 2016 PDF


*igher compared with lower dietary protein during an

energy deficit com#ined with intense exercise

promotes greater lean mass gain and fat mass loss$ a

randomi2ed trial, #y ongland, 0ikawa, Mitchell,

8evries, 3 Phillips, in 'he (merican Journal of +linical

Nutrition 5/.7 "

Background

;rotein supplementation ma be provided from several

different sources and some researchers have

suggested that the use of either whe, casein or

essential amino acids ma lead to different effects,

most liel b altering the rate of muscle protein

snthesis or muscle protein breadown post-exercise.

or a more detailed introduction to protein and

resistance training, see the earlier stud review.

OBJC!"#$ o identif whether altering dietar

protein intae during an energ deficit and in

combination with a concurrent resistance training and

high-intensit interval training #/II' program would

produce changes in bod composition #measured b

using a 6-compartment modelG total bod volume was

measured with air-displacement plethsmograph

#Bod;od', total bod water was measured withbioelectrical impedance, and bone mineral content was

measured using dual-energ N-ra absorptiometr

DENAC' and muscle strength #as measured b &+

bench press and &+ leg press'.

%O%&'(!"O)$ 6% oung males, aged $7 5 $ ears,

randoml assigned to either a low-protein #@3W, &.$g

per g of bod mass per da' or a higher-protein

#/I0/, $.6g per g of bod mass per da' diet.

")!*#)!"O)$ All sub<ects consumed diets that

provided 77 5 & cal per g of lean bod mass,

representing a 6% 5 7* reduction in habitual energ

intae. he sub<ects were provided with all meals and

beverages during the intervention #except for waterand noncaloric drins'. he sub<ects performed a

program of exercise training, 2 das per wee. his

program included $ das of resistance training, $ das

of /II, & da of a $4%K ccling time trial, and & da

of plometrics. In addition, the sub<ects were re=uired

to wear a hip-worn pedometer and accumulate &%,%%%

steps per da throughout the 6-wee period.

What happened?

Effects on #ody composition

he researchers calculated that lean bod mass

increased in /I0/ #b &.$ 5 &.% g', and this increase

was larger than the increase in @3W #%.& 5 &.% g'.

Additionall, the found that /I0/ lost more fat mass

than @3W #6.) 5 &.2 vs. 7.4 5 &.6g'. he noted

that changes in serum cortisol during the intervention

were associated with both the changes in bod fat #r

L %.78' and lean bod mass #r L -%.76'.

Effects on #ench press .4M and leg press .4M

he researchers reported that there were significant

increases in bench press &+ and leg press &+ in

both /I0/ and @3W groups. he increases were =uite

substantial. he increase in leg press &+ in /I0/

was from &:& 5 7% to 76% 5 ::gM in @3W, leg press

&+ increased from &2$ 5 7% to 7&) 5 2$g. he

increase in bench press &+ in /I0/ was from &%: 5

$8 to &62 5 44gM in @3W, bench press &+ increasedfrom 88 5 &6 to &$2 5 72g.


he researchers concluded that consuming a higher

protein diet during an energ deficit while performing

resistance training and /II, leads to increases in lean

bod mass in a 6-wee period, which are accompanied

b large increases in strength.

'imitations

he stud was performed in untrained sub<ects with

capacit for large improvements in muscle strength.


http://ajcn.nutrition.org/content/early/2016/01/26/ajcn.115.119339.abstract

http://ajcn.nutrition.org/content/early/2016/01/26/ajcn.115.119339.abstract

8/18/2019 Scr Mar 2016 PDF


Protein reBuirements #eyond the 48() implications

for optimi2ing health, #y Phillips, +hevalier, 3 eidy,

in (pplied Physiology, Nutrition, and Meta#olism

5/.7 "

Background

;rotein supplementation ma be provided from severaldifferent sources and some researchers have

suggested that the use of either whe, casein or

essential amino acids ma lead to different effects,

most liel b altering the rate of muscle protein

snthesis or muscle protein breadown post-exercise.

or a more detailed introduction to protein and

resistance training, see the earlier stud review.

OBJC!"#$ he researchers performed a narrative

review, detailing conclusions based upon presentations

at the $%&4 1anadian >utrition "ociet conference,

(dvances in Protein Nutrition across the ifespan in

relation to the recommended dail allowance #+DA'

for dietar protein intae.

What happened?

Pro#lems with the current 48(

he researchers note that the current +DA for dietar

protein intae in the "A and 1anada is %.)g per g of

bodweight per da for all adults including the elderl.

/owever, this is despite the apparent detrimental

effects of consuming protein doses of this level, in

comparison with higher amounts. or example, in

cohort studies of elderl people, the loss of lean

muscle mass is less in individuals consuming high

protein intaes #&.$g per g of bodweight per da'

than in those consuming the +DA #%.)g per g of

bodweight per da', and it is associated with a

reduced ris of developing frailt.

Misplaced concerns over health impact

he reviewers note that despite the clear beneficial

effects of protein consumption, some sources continue

to suggest that higher protein intaes lead to renal

failure or reduced bone health. he state that neither

of these riss has an foundation for currentl health

individuals. In fact, when increasing dietar protein

intae, there is actuall an increase in glomerular

filtration rate, and the direction of the correlation of

creatinine clearance with protein intae is positive,

suggesting that it is low protein intake that leads to

decreased renal function. +egarding the effects of high

protein intae on bone health, the reviewers explain

that this is the Hacid-ash hpothesis in which it issupposed that diets with higher protein or grain foods,

with a low potassium intae, produce a greater dietar

acid load, causing higher net urinar acid excretion,

greater urinar calcium excretion, and this excreted

calcium is assumed to impl the loss of bone calcium.

/owever, this final step has never been demonstrated,

and when calcium intaes are ade=uate, higher

protein intaes actuall seem to be supportive of

better bone health.


he researchers concluded that current evidence does

not indicate an grounds for health concerns regarding

higher protein intaes, and in fact supports the use of intaes in the range of &.$ ( &.2g per g of

bodweight per da of high-=ualit protein as the best

target for optimal health outcomes in most adults.

he suggest that older adults ma re=uire even

higher intaes #&.$ per g of bodweight per da' to

help prevent the onset of sarcopenia.

'imitations

he stud was a narrative review, and ma not reflect

the views of all researchers woring in this field.


http://www.nrcresearchpress.com/doi/abs/10.1139/apnm-2015-0550

http://www.nrcresearchpress.com/doi/abs/10.1139/apnm-2015-0550

8/18/2019 Scr Mar 2016 PDF


+0K$inhi#itor influence on skeletal muscle fi#er si2e

and meta#olic adaptations to resistance exercise in

older adults, #y 'rappe, 4atchford, &rower, iu, avin,

+arroll, 3 'rappe, in 'he Journals of !erontology

%eries ( 5/.7 "

Background"arcopenia is a sndrome involving low muscle mass

and reduced muscle function, tpicall observed in an

aging person. "arcopenia involves a generali9ed loss

of muscle rather than a locali9ed loss of muscle or

muscle group-specific loss of muscle and ma follow

primaril from disuse atroph. +ecent estimates have

suggested that the loss of muscle mass occurs at a

rate of 7 ( )* per decade after the age of 7% and that

a higher rate of muscle loss occurs in old age. hus,

sarcopenia is a e problem in geriatrics and leads to

an increased ris of several adverse health outcomes,

including phsical disabilit, poor health-related

=ualit of life and increased mortalit. he prevalence

of sarcopenia ranges widel from : ( 2)*, depending

on age, geograph and circumstances of the

individuals involved. An increased prevalence of

sarcopenia is seen in older adults, individuals living in

residential nursing homes, individuals who have

experienced fractures, individuals who habituall

perform low levels of phsical activit, individuals with

a low bod mass index #BI', and in those who score

low on functional tests such as single leg stance time

and handgrip strength, or who have a histor of falls.

"ome studies indicate that sarcopenia ma involve a

preferential loss of tpe II muscle fiber area and

muscle fiber number as a result of denervation. An

inabilit to stimulate muscle protein snthesis via

signaling and increased oxidative stress ma also be a

contributing factor leading to accelerated muscle

wasting. "ince a number of studies have found that

aerobic exercise, resistance training and concurrent

training programs are able to combat sarcopenia,

guidelines have been produced to provide exercise

information for elderl people. or example, the

American 1ollege of "ports edicine #A1"'

recommends that for aerobic exercise, older adults

should perform moderate intensit aerobic activit for

P7% minutes, 4 das of the wee or vigorous exercise

for P$% minutes, 7 das of the wee. he A1"

recommends that for resistance training, older adults

should perform bi-weel muscle strengthening

activities of ) ( &% exercises for &% ( &4 repetitions.

Interestingl, however, studies have shown that theloss of muscle mass in sarcopenia is onl partiall

correlated with the loss of strength, which appears to

be much more rapid. hus, it appears that there ma

be neural factors associated with the loss of muscle

strength in the elderl, which ma include reductions

in voluntar muscle activation. Indeed, there are

indications that the loss of muscle power ma in fact

reduce at a greater rate than the loss of muscular

strength. his is important, as some studies have

reported that muscle power is more influential than

muscular strength in determining performance on

functional tass in the elderl population.

OBJC!"#$ o find out if common cclooxgenase

#13N'-inhibiting drugs alter the extent of resistance

training-induced changes in muscle volume #as

measured b magnetic resonance imaging #+I'

scans', changes in tpe I or tpe II muscle fiber si9e

#as measured b taing muscle biopsies from the

vastus lateralis, and using A;ase histochemistr',

and changes in muscle fiber capillari9ation andmetabolic en9me activities #glcogen phosphorlase,

citrate snthase, X-hdroxacl-1oA-dehdrogenase',

using similar methods.

%O%&'(!"O)$ &4 health older males, randoml

allocated into either a placebo group #;@A1, )

sub<ects, aged 26 5 $ ears' or a 13N-inhibitor group

#13N, : sub<ects, aged 26 5 & ears'.

")!*#)!"O)$ Both groups performed &$ wees of

nee-extensor resistance training, involving 7 sets of

&% repetitions to muscular failure, with $ minutes of

rest betweens sets, 7 das per wee. During the &$-

wee period, 13N group consumed acetaminophen

#6g per da', while the ;@A1 group consumed onl aplacebo.

What happened?

Effect on muscle si2e

he researchers found that =uadriceps muscle volume

increased significantl in both groups, but the increase

was significantl greater in the 13N group than in the

;@A1 group. In addition, the found that tpe I fiber

si9e did not change with training in the ;@A1 group

but increased b $)* in the 13N group. In the ;@A1

group, tpe II fiber si9e increased b $2*, and in the

13N group, tpe II fiber si9e increased b 7:*.

Effect on capillari2ation and en2yme activity he researchers reported that muscle capillari9ation

and en9me activit were maintained constant in the

;@A1 group, whereas, capillar-to-fiber ratio increased

b $6* in the 13N group, and activit of the oxidative

en9me, citrate snthase, increased b &)*. hese

two findings #which are more normall associated with

endurance exercise' are supportive of an increased

role of tpe I muscle fibers in the 13N group.


he researchers concluded that consuming a 13N-

inhibitor in con<unction with resistance training in

older individuals increases the extent of the change in

muscular si9e, but this effect is produced mainlthrough an increase in tpe I muscle fiber si9e.

'imitations

he stud was limited insofar as it is unclear whether

the enhancement in muscle growth b means of the

increase in tpe I muscle si9e through use of the 13N-

inhibitor leads to an differences in functional or

health status, in comparison with conventional muscle

growth.


http://biomedgerontology.oxfordjournals.org/content/early/2016/01/26/gerona.glv231.abstract

http://biomedgerontology.oxfordjournals.org/content/early/2016/01/26/gerona.glv231.abstract

8/18/2019 Scr Mar 2016 PDF


Eating freBuency, food intake, and weight) systematic

review of human and animal experimental studies, #y

4aynor, !off, Poole, 3 +hen, in @rontiers in Nutrition

5/.6 "

Background

Weight loss is achieved b altering the balancebetween the amount of energ consumed #E1' and

energ expended #EE'. Weight loss can therefore be

achieved either b reducing E1, increasing EE, or a

combination of both. his is commonl called dieting,

exercising, or combining both diet and exercise. ost

people tend to instinctivel identif diet as the primar

wa to lose weight, although man also include

exercise as an extra tool. Even so, there are widel

varing opinions regarding the optimal was to lose

weight and experts have made widel diverging

recommendations about the best diet, exercise

program, or combination. Weight loss re=uires an

energ deficit. An energ deficit occurs when E1 is

smaller than EE #so the energ balance is negative'.

In contrast, an energ surplus is where E1 is larger

than EE #so the energ balance is positive'. When

there is an energ deficit for a sustained period of

time, people lose weight #usuall mostl from fat

reserves' while when there is an energ surplus for a

period, people gain weight #again, mostl stored as

fat'. E1 is provided entirel b food consumption, so is

relativel eas to calculate, as long as it is accuratel

recorded. EE is much harder to measure, as it is made

up of several parts, including the resting metabolic

rate #++'M the energ re=uired for moving around,

which is called phsical activit energ expenditure

#;AEE'M and the calories used for processing food,

which is called the thermic effect of food #E'. ;AEE

can be further divided into the energ used during

phsical activit performed as exercise #ENEE' and

energ used during other tpes of phsical activit,

called non-exercise activit thermogenesis #>EA'.

an studies have shown that when an energ deficit

is created, weight loss is tpicall less than

anticipated. ailure to achieve expected weight loss is

caused b compensator mechanisms, which are

changes that reduce the si9e of the energ deficit

produced b planned changes in E1 or EE. he

include increases in E1, which is where people are

tempted to consume more food or more energ dense

foods, reductions in ++, which is where less energ

is used to maintain basic functions #lie breathing' at

rest, reductions in ;AEE, b maing both ENEE and>EA more efficient #so the same amount of wor

burns fewer calories', and reductions in the total

volume of >EA, which is where the reduce the

amount of spontaneous phsical activit.

OBJC!"#$ o perform a sstematic review of

experimental studies investigating the effect of a

greater eating fre=uenc on E1 andFor anthropometric

measures, in both human and animals.

S!&+, S'C!"O)$ "tudies were included involving

humans, either where E1 was assessed via dail food

intae, or food intae during an ad libitum meal, orwhere an anthropometric outcome was measured after

a period of time, such as bod mass index #BI' or

bodweight. "tudies were also included involving

animals with similar criteria, involving studing the

effects of manipulating increasing eating fre=uenc on

either a measure of E1 or on subse=uent changes in

bodweight.

What happened?

%tudy selection

he researchers identified $4 studies #&4 human and

&% animal studies' with various stud designs, varing

eating fre=uencies #& ( $6 eating occasions per da',

widel-ranging lengths of investigation #$7% minutesto $) wees', and sample si9es #7 ( 42 sub<ects or

animals per condition'. In human studies, there were

&& trials in controlled laborator conditions and 4 trials

in field settings.

Effects of eating freBuency in humans

Among controlled studies, the researchers found that

out of 2 studies that used an ad libitum meal to

measure E1, 7 studies reported lower E1 with higher

eating fre=uenc, while 7 studies found no difference

between conditions. he found that out of 4 studies

that measured anthropometrics, 6 observed no effect

as a result of eating fre=uenc, while & found a lower

outcome with a higher eating fre=uenc. he noted

that out of 6 studies in which EE was measured, &

reported that a higher eating fre=uenc produced a

significantl lower EE, which was achieved b means

of reduced E. he observed that out of 2 studies

that recorded measures of self-reported appetite, 7

found reduced self-reported hunger with higher eating

fre=uenc. In the field-based studies, the researchers

found that in the & stud reporting on E1, there was

no effect of eating fre=uenc. he found that out of

the 6 studies reporting on changes in bodweight, 7

found no effect of eating fre=uenc, while & found a

greater bodweight with higher eating fre=uenc.

rom & stud, it appeared that EE was not affected b

eating fre=uenc, while & stud reported that hunger

was lower with higher eating fre=uenc.


he researchers concluded that there is onl minimal

evidence that eating fre=uenc has an effects on E1

or bodweight.

'imitations

he stud was limited b the small number of studies,

and future research ma reveal other results as the

result of further wor in this area.




8/18/2019 Scr Mar 2016 PDF


&ody composition and energy intake L skeletal

muscle mass is the strongest predictor of food intake

in o#ese adolescents) the *E(4'A 'rial, #y +ameron,

%igal, <enny, (l#erga, Prud*omme, Phillips, 3

!oldfield, in (pplied Physiology, Nutrition, and

Meta#olism 5/.7"

Background

Weight loss is achieved b altering the balance

between the amount of energ consumed #E1' and




exercising, or combining both diet and exercise. or a

detailed introduction to weight loss and E1, see the

earlier stud review.

OBJC!"#$ o identif if there are an metabolic or

anthropometric predictors of E1 in overweight andFor

obese adolescents using linear regression analsis,

including resting metabolic rate #++' #measured b

b indirect calorimetr' and bod composition #as

measured b magnetic resonance imaging +IC',

where E1 #in cal per da' was measured using 7-da

food records.

%O%&'(!"O)$ 7%6 overweight or obese post-

pubertal adolescents #8% bos and $&: girls' aged

&2.& 5&.6 ears.

What happened?

Predictors of E+

sing linear regression analsis, the researchers found

that bodweight, ++, lean bod mass, muscle mass,

and fat mass were all significantl correlated with E1.

/owever, in a model that was ad<usted for age, sex,

height, and phsical activit levels, onl lean bod

mass and muscle mass remained significant predictors

of E1.


he researchers concluded that muscle mass is the

best predictor of E1 in inactive, obese adolescents.

'imitations

he stud was limited, as it was unclear whether the

same results would be observed in obese adults, non-

obese adults, or in non-obese adolescents.


8/18/2019 Scr Mar 2016 PDF


ow energy availa#ility in exercising men is associated

with reduced leptin and insulin #ut not with changes

in other meta#olic hormones, #y <oehler, *oerner,

!i##s, >inner, &raun, 8e %ou2a, 3 %chaen2er, in

Journal of %ports %ciences 5/.7 "

BackgroundWeight loss is achieved b altering the balance

between the amount of energ consumed #E1' and




exercising, or combining both diet and exercise. or a

detailed introduction to weight loss and E1, see the

earlier stud review.

OBJC!"#$ o measure the endocrine effects #as

measured using blood samples' of low energ

availabilit during exercise.

%O%&'(!"O)$ 2 males, aged $4.$ 5 &.% ears.

")!*#)!"O)$ All of the sub<ects participated in 6

conditions each lasting 6 das, involving low #@3W' or

normal #13>+3@' energ availabilit, and either

exercise #EN' or no-exercise #>EN'. he EN conditions

involved expending &4 cal per g of lean bod mass

per da while >EN involved performing no exercise.

he @3W conditions involved consuming &4 cal per

g of lean bod mass per da after ad<usting for

exercise #i.e. @3W->EN consumed &4 cal per g of

lean bod mass per da, while @3W-EN consumed 7%

cal per g of lean bod mass per da', while >3+A@

consumed 6% cal per g of lean bod mass per da.

he energ consumed was based upon detailed meal

plans provided b the researchers, with macronutrient

guidelines of 4% ( 44* carbohdrate, 7% ( 74* fat,

and &% ( &4* protein. he exercise was supervised

and was performed on a ccle ergometer.

What happened?

Effects of exercise and energy availa#ility

In both @3W->EN and @3W-EN, leptin was significantl

reduced #b around 47 ( 42*' and insulin was also

reduced #b 76 Q 7)*' but there was no significant

difference between @3W->EN and @3W-EN. he

researchers also observed reductions in fasting

glucose #b ) Q &$*', increases in glcerol #)) (

&2:*' and free fatt acids #:% ( &&$*'. here was

no effect of energ availabilit on ghrelin, I0-&,

testosterone, or triiodothronine.


he researchers concluded that the si9es of the

changes in leptin and insulin levels that occurred as a

result of the short-term interventions did not differ

whether the were achieved through diet or diet plus

exercise.

'imitations

he main limitation of the current stud was its short-

term duration, and longer periods might reveal the

presence of some differences between diet and diet

plus exercise interventions.




8/18/2019 Scr Mar 2016 PDF


Muscle memory and a new cellular model for muscle

atrophy and hypertrophy, #y !undersen, in 'he

Journal of Experimental &iology 5/.7 "

Background

uscles are formed from bundles of fascicles, which in

turn comprise bundles of muscle fibers or muscle cells.nlie most other cells in the human bod, muscle

fibers contain man hundreds of nuclei. It is thought

that this uni=ue arrangement occurs because muscle

fibers are formed b the fusion of multiple different

moblasts in development. his fact ma be connected

to the remarable abilit of muscle fibers to

regenerate after in<ur. Indeed, rather radical, earl

studies in the &82%s found that it was possible to

remove muscles from animal sub<ects, mince them

and replace them in situ. he replaced, minced muscle

was found to regain function after as little as 7 wees

of recuperation. his regenerative abilit occurs in a

similar manner to the wa in which muscle fibers grow

in development. oblasts fuse together and form

new motubes, or fuse to pre-existing, damaged

muscle fibers to replace lost nuclei. his regenerative

process can involve the generation of thousands of

moblasts each time. "atellite cells #also called

seletal muscle stem cells' are involved in this process

of moblast generation. "atellite cells are so-called

because the are found directl ad<acent to muscle

fibers, between the sarcolemma and basement

membrane. In addition to producing moblasts,

satellite cells also maintain their own population b

self-renewal, as expected of a stem cell. hus, the

main role of the satellite cell during development is to

provide nuclei for muscle growth. 3n the other hand,

the main role of the satellite cell in adult muscle is

simpl to maintain homeostasis and assist with either

hpertroph following a training stimulus or repair

following muscle in<ur. Whether the availabilit of

satellite cells places a limit on muscular hpertroph is

unclear. Earl studies exploring this =uestion found

that irradiation of seletal muscle and elimination of

the satellite cells prevented hpertroph. ore recent

investigations have found that hpertroph can occur

without an contribution from satellite cells, although

the appear to be activated under most normal

circumstances. he mechanisms that are responsible

for the molecular events through which satellite cells

are activated, proliferate, and differentiate are

currentl unclear. Endogenous testosterone could be

one factor, particularl as previous research hasidentified that satellite cells can be targets for

testosterone action through the androgen receptor, as

researchers have reported exogenous testosterone

increases the number of satellite cells, and since

observational trials have reported positive associations

between testosterone, increases in muscular si9e, and

the number of satellite cells.

OBJC!"#$ o perform a narrative review to explore

the mechanism b which the phenomenon of Hmuscle

memor might be explained. he phenomenon of

muscle memor is the condition whereb muscle fibers

that have formerl been large, but which subse=uentl

lose their si9e, can regain this large si9e faster than

similar muscle fibers that have never previousl

achieved the same degree of hpertroph.

What happened?

%atellite cells

"atellite cells are important plaers in the process of

hpertroph. he contribute the monuclei that are

used to expand the si9e of muscle fibers, allowing the

muscle cell to maintain a constant or near-constant

monuclear domain. A constant monuclear domain is

necessar for the increases in muscle si9e to remain

functional. Importantl, the reviewer explains that

although there are clear increases in the number of

monuclei during hpertroph, several studies have

found no subse=uent reductions in monuclei with

detraining and atroph, even in the context of ver

large reductions in muscle si9e.

Muscle memory mechanism

he reviewer notes that since there is no loss in the

number of monuclei in detraining and subse=uent

muscle atroph, this creates a possible mechanism for

muscle memor, as it allows for hpertrophic growth

during re-training that can occur without the need for

an recruitment of monuclei, up to the previous si9e

of the muscle before detraining commenced. he

reviewer notes that in this wa, a previousl large

Htrained muscle fiber would differ from an alwas

small Huntrained muscle fiber, because it would have

a greater number of monuclei, and thereb have a Hmemor of its past histor as a big muscle. he

reviewer notes that the technical term for this

behavior is Hhsteresis, as the muscle cell behavior is

altered b its previous exposure to hpertroph-

inducing mechanical loading.


he researcher concluded that the involvement of

satellite cells in adding monuclei during hpertroph

but not removing monuclei during atroph might

explain the phenomenon of Hmuscle memor wherein

muscles that were previousl large can more easil

regain their former si9e than previousl untrained

muscles. his has important ramifications for publichealth, as resistance training at oung ages while still

in school might be one wa of ensuring greater abilit

to build muscle in later life. In addition, it has star

implications for anti-doping, as it suggests that those

athletes who use muscle-building performance-

enhancing substances, such as anabolic androgenic

steroids, might be able to use them earl in their

career and et en<o benefits for ears afterwards.

'imitations

he stud was a narrative review, performed b a

single author, and their views ma not reflect the

opinions of all researchers woring in this field.




8/18/2019 Scr Mar 2016 PDF


( newly discovered muscle the tensor of the vastus

intermedius, #y !ro#, (ckland, <uster, Manestar, 3

@ilgueira, in +linical (natomy 5/.7 "

Background

here are four main =uadriceps musclesG the rectus

femoris, the vastus lateralis, vastus medialis, andvastus intermedius. he originate either from the

medial or lateral aspects of the femur inferior to the

acetabulum, or in the case of the rectus femoris from

the ilium and inferior iliac spine. he insert at the

base, lateral, and medial aspects of the patella,

converging to a common =uadriceps tendon on the

patella and tibia. he =uadriceps are primar nee

extensors, while the two-<oint rectus femoris is also a

hip flexor. he =uadriceps also stabili9e the nee b

regulating the medial and lateral forces pulling on the

patella and potentiall preventing its malalignment.

he =uadriceps var in si9eG the vastus lateralis is the

largest and the rectus femoris is the smallest, at

around half its volume. he muscle cross-sectional

area of the =uadriceps also varies and each displas it

largest cross-sectional area at different locations along

the femur. he =uadriceps var in muscle architecture.

he vastus medialis displas the greatest muscle

thicness, followed b the vastus lateralis, rectus

femoris and vastus intermedius. he vastus medialis

obli=ue is the most heavil pennated, followed b the

rectus femoris, while the three vastus muscles displa

the longest muscle fascicles. he vastus lateralis has

the largest force-producing abilit owing to its large

phsiological cross-sectional area. he =uadriceps

displa their largest moment arm lengths in the mid-

range of nee flexion. he displa their minimum

moment arm lengths at both shallow and ver deep

nee angles. oment arm length increases with force

from % ( :4* of maximum voluntar isometric

contraction #JI1' force depending on nee <oint

angle. 0reater changes in moment arm length as a

result of force production occur at shallower nee

flexion angles compared with deeper nee flexion

angles. he =uadriceps displa a relativel mixed

proportion of muscle fibers. he rectus femoris

displas the smallest proportion of tpe I muscle

fibers, while the vastus lateralis, vastus medialis and

vastus intermedius displa between 66 ( 26* of tpe

I muscle fibers. his ma impl that training with a

mixture of both lighter and heavier loads is beneficial

for these muscles. Although the =uadriceps cannot be

activated individuall, some exercises displa greaterlevels of electromograph #E0' amplitude in certain

of the muscles than others. or example, vastus

medialis obli=ue muscle activation is superior when

performing the s=uat with slower than normal speeds,

when using single-leg dnamic muscle actions

#compared to isometric', and training with mid-range

nee flexion angles. ;erforming the s=uat with added

hip adduction ma also produce a more favorable

vastus medialis obli=ue to vastus lateralis muscle

activit ratio.

OBJC!"#$ o perform an anatomical investigation

b dissecting the =uadriceps musculature of cadavers,

in order to explore whether there is an additional

separate muscle, the tensor vastus intermedius.

%O%&'(!"O)$ $2 lower limbs from &2 embalmed

cadavers #being 8 males #2 paired and 7 unpaired'

and : females 6 paired and 7 unpairedC'.

")!*#)!"O)$ he thighs were examined through

a standardi9ed dissection protocol.

What happened?

Presence of tensor vastus intermedius

he researchers identified that in all of the dissections

there was a separatel-innervated tensor vastus

intermedius muscle, which was located between the

vastus lateralis and the vastus intermedius. his new

muscle <oined with the other =uadriceps muscles at

the distal tendon, b inserting into the middle laer of

the =uadriceps tendon, which attaches to the patella.

In most #$$F$2' of the cases investigated, theproximal attachment was separate from the other

=uadriceps, whereas in a few #6F$2' cases, it was not

clearl separate from the other muscles.

@eatures of tensor vastus intermedius

he researchers identified that the origin of the tensor

vastus intermedius was on the anterior aspect of the

greater trochanter of the femur, although some fibers

also infiltrated into the gluteus minimus insertion on

the same structure. his origin is ver close to that of

the vastus lateralis and vastus intermedius. "imilarl,

the innervation of the tensor vastus intermedius was

found to originate from the same lateral, and deep

branch of the femoral nerve as these muscles. he

researchers observed that the si9e of the tensorvastus intermedius varied greatl between sub<ects.


he researchers concluded that the have discovered

a new muscle, which the describe as the tensor

vastus intermedius. he suggest that the tensor

vastus intermedius fulfils the necessar criteria for an

independent muscle, having independent innervation

through separate branches of the femoral nerve, and a

clear origin on the anterior aspect of the greater

trochanter of the femur, although it inserts alongside

the other =uadriceps muscles on the =uadriceps

tendon that attaches to the patella.

'imitations


cadavers, and it is unclear to what extent this new

muscle behaves independentl from the other nee

extensors, if it does at all.




8/18/2019 Scr Mar 2016 PDF


/% PH*SICAL THERAP* AND REHA+ILITATION


8/18/2019 Scr Mar 2016 PDF


'he relationship #etween training load and injury,

illness and soreness) a systematic and literature

review, #y 8rew 3 @inch, in %ports Medicine 5/.7 "

Background

"ports in<ur is a serious problem for both individual

and team sports athletes. A common wa in whichresearchers attempt to reduce the incidence of sports

in<ur is to identif ris factors for either in<ur in

general or certain, specific in<uries that are tpicall

ver problematic, such as hamstring strains. Where

ris factors can be identified in athletes, it is assumed

that taing action can limit their effects #either b

reducing the exposure of that athlete to dangerous

scenarios, or b attempting to modif the ris factor

through training interventions'. +is factors are

commonl explored in observational trials. he can

be assessed either retrospectivel #b looing at

historic data to assess the factors that predict in<ur

ris' or prospectivel #b following a group of athletes

intentionall in order to measure specific, pre-

determined ris factors'. ;rospective in<ur trials are a

better =ualit of stud design as the reduce the ris

of identifing a false-positive result. In addition, there

are several was in which the statistical analsis can

be performed on ris factors. In general, in<ur ris

factors are assessed using either odds ratios or

relative riss. hese are ver different calculations and

should not be confused. 3dds ratios measure the

probabilit of an event occurring relative to the

probabilit that it does not occur. +elative ris is the

multiple of the ris of an outcome occurring in one

group as a result of an exposure, compared to the ris

of the same outcome in another group. he main

difference between odds ratios and relative riss is

therefore that relative riss also tae into account the

amount of exposure. In general, relative riss are

considered to be a slightl superior wa of assessing

ris factors. /owever, there are two other e

measures to be aware ofG sensitivit and specificit.

"ensitivit is the percentage of sub<ects who have an

underling predisposition to in<ur and who are

correctl identified beforehand b the test #i.e. wea

hamstrings'. "ensitivit is sometimes called a test of

Htrue positives because it rates a test solel based on

its abilit to flag positive results. Where sensitivit is

high, there is little chance of failing to detect an

underling predisposition to in<ur. /owever, a test

with good sensitivit can still be poor at clearing

sub<ects who do not have an underling predispositionto in<ur. "pecificit refers to the percentage of

sub<ects who do not incur an in<ur and who are

correctl identified b a test #i.e. strong hamstrings'.

"pecificit is sometimes called a test of Htrue

negatives because it rates a test solel based on its

abilit to flag negative results. Where specificit is

high, there is little chance of failing to clear a sub<ect

who is not at ris. A test with good specificit can

therefore still be ver poor at identifing sub<ects who

are actuall at ris.

OBJC!"#$ o perform a sstematic review in order

to identif the relationships between training and

competition loads, and in<ur or illness, and to assess

the =ualit of the studies #with the >ewcastle(3ttawa

"cale >3"C'.

S!&+, S'C!"O)$ "tudies were included where

the anal9ed the relationship between training orcompetition loads and either in<ur or illness, in

athletes of an age or level of competition.

What happened?

%tudies selected

he researchers identified 74 studies that met the

inclusion criteria. he largest proportion of the studies

evaluated the nature of the relationships between

in<uries and training load in rugb league plaers #8

studies' followed b cricet #4 studies', soccer #7

studies', Australian ootball #7 studies', rugb union

#$ studies', volleball #$ studies', baseball #$ studies',

and other sports for which onl a single stud each

was identified. he researchers found that the median>3" score for in<ur and illness was ) #range L 4 ( 8

points' and 2 #range L 4 ( 8 points', respectivel.

4elationships identified

he researchers found some moderate evidence for

the existence of a relationship between higher training

loads and increased in<ur incidence in most #87*' of

the studies, as well as with increased illness incidence

#:4*'. /owever, training loads were also reported to

have a protective effect against in<ur #7&*' and

illness #&7*'. his suggests that some appropriate

#low-to-moderate' level of training load is protective,

while a higher level ma be damaging.


he researchers concluded that there is moderate

evidence for a positive relationship between training

load and the occurrence of in<ur and illness.

'imitations

he review was limited as it included a range of

studies in ver different sporting populations, and

there ma be heterogeneit in respect of the training

status of the athletes and their sports.




8/18/2019 Scr Mar 2016 PDF


Neck muscular strength, training, performance and

sport injury risk) a review, #y *rysomallis, in %ports

Medicine 5/.7 "

Background

"ports in<ur is a serious problem for both individual

and team sports athletes. A common wa in whichresearchers attempt to reduce the incidence of sports

in<ur is to identif ris factors for either in<ur in

general or certain, specific in<uries that are tpicall

ver problematic, such as hamstring strains. or a

detailed introduction to sports in<ur, see the earlier

stud review.

OBJC!"#$ o perform a narrative review of nec

muscle strength in sport, b comparing the nec

strength of different athletes, b examining the effects

of nec training programs, b exploring associations

between nec strength and head stabilit, and finall

b examining the relationship between nec strength

and sports in<ur ris.

What happened?

+omparison of neck strength #etween athletes

he reviewer explains that direct comparisons of nec

strength between athletes of multiple sports are not

available. /owever, it has been found that athletes

have greater nec strength than non-athletes for

ccling and wrestling, while in rugb union, forwards

have greater nec strength than bacs, and in

American ootball, linemen have stronger necs than

running bacs. In both cases, this strength ma be

associated with the larger nec girths.

Effects of neck training programs

he reviewer notes that training studies in athletesfrom soccer, American ootball, and rugb union have

reported increases in nec strength, using either

dnamic or isometric nec exercises, with most using

nec extension, and some also including flexion and

lateral flexion.

(ssociations #etween neck strength and head sta#ility

he reviewer found that at the present time, there

was onl limited evidence to support an association

between nec strength and head stabilit.

4elationship #etween neck strength and injury risk

he reviewer explains that one prospective stud

performed in a large group of high-school athletes

found that higher maximal isometric nec strength#measured preseason for flexion, extension and lateral

flexion using a hand-held tension scale' significantl

reduced the ris of concussion. "pecificall, concussed

athletes had && ( $$ * less nec strength than the

athletes who were not concussed. In addition, the

reviewer noted that one stud identified that isometric

nec strengthening training produced a significant

reduction in the number of match-related cervical

spine in<uries in rugb union plaers.


he researcher concluded that there are differences in

nec strength between athletes, which seem to be

partl caused b differences in nec muscle mass, thatspecific strength training programs generall produce

increases in nec strength, and that isometric nec

strength and training are related to nec in<ur and

concussion ris in sport.

'imitations

he stud was a narrative review, performed b a

single author, and their views ma not reflect the

opinions of all researchers woring in this field.




8/18/2019 Scr Mar 2016 PDF


( comparison of two stretching programs for

hamstring muscles) a randomi2ed controlled assessor$

#linded study, #y 8emoulin, :olfs, +hevalier,

!ranado, !rosdent, 8epas, 3 9anderthommen, in

Physiotherapy 'heory and Practice 5/.7 "

Backgroundlexibilit is important for both athletes and for the

general population. lexibilit is defined as the abilit

to move through a specific <oint range of motion

#+3'. "tretching is commonl used to help

individuals achieve greater <oint +3. +esearchers

have generall proposed two tpes of mechanism b

which increases in flexibilit can be achieved. 3ne

tpe of mechanism involves a mechanical change in

the behavior of the muscle tissue while the other tpe

involves a change in sensation. /owever, there are at

least four theories that detail was in which some ind

of mechanical change could occurG viscoelastic

deformation, plastic deformation, increased number of

sarcomeres in series, and neuromuscular relaxation.

/owever, the evidence to support these has been

found to be wea. In contrast, man studies have

reported that the onl variable that changes following

stretching programs in tandem with flexibilit is the

sensation of pain #i.e. maximum pain and onset of

pain' during the stretch. his supports the sensation

theor of stretching. +esearchers advocating this

theor have formulated the hpothesis that stretching

increases flexibilit b reducing the sensation of

increasing muscle length. >evertheless, irrespective of

how stretching changes <oint flexibilit, it is apparent

that it can achieve increases in <oint +3 that last P &

da. here are two main tpes of stretching that are

explored in the literatureG static and dnamic

stretching. "tatic stretching involves moving a <oint to

the end of its +3 and holding this stretched position

for a set period of time. 3n the other hand, dnamic

stretching involves controlled movements through the

active +3 for a <oint. While both static and dnamic

stretching have been found to improve <oint +3,

static stretching performed for P64 seconds appears

to lead to meaningful acute reductions in performance

tass, such as vertical <umping, whereas dnamic

stretching performed for long durations appears to

lead to either no improvement or small improvements

in the same tpe of actions. It is interesting to note

that reviews of the chronic effects of static stretching

have actuall found beneficial effects on both athletic

performance and strength measures. he literature iscurrentl conflicting regarding whether regular static

or dnamic stretching is effective for reducing the ris

of sports in<ur, whether the stretching is performed

immediatel prior to exercise or at another time.

Additionall, the exact duration of stretches, the total

volume and fre=uenc of stretching per wee, and the

rest periods between stretches that are optimal for the

most efficient increases in <oint +3 are currentl

unnown.

OBJC!"#$ o compare the effects of two different

hamstring stretching programs on long-term changes

in hip flexion +3 #using the straight-leg raise test'

and nee extension +3 #as measured using the

passive nee extension angle test'.

%O%&'(!"O)$ &&& asmptomatic participants with

tight hamstring muscles #passive nee extension testangle L 7&.4 5 2.4 degreesM mean straight-leg raise

test angle L 22 5 :.2 degrees'. "ub<ects were

randoml allocated into either a control #13>' group,

aged $$.% 5 $.6 ears, a hip flexion stretching #/I;'

group, aged $$.4 5 $.8 ears, or a nee extension

stretching #R>EE' groups, aged $&.4 5 &.8 ears.

")!*#)!"O)$ Each of the two stretching groups

performed one of two different home-based )-wee

stretching programs, both of which involved 4 sessions

per wee, lasting &% minutes per session. he /I;

group stretched b flexing the hip while eeping the

nee extended, while the R>EE group stretched b

first flexing the hip with a flexed nee and then

extending the nee.

What happened?

+omparison #etween stretching programs


both hip flexion +3 and nee extension +3 after

both /I; and R>EE stretching programs, compared to

the 13> group. /owever, there were no differences

between the two stretching groups for either test.


he researchers concluded that during hamstring

stretching programs, stretching either at the hip or the

nee has similar effects on hip flexion +3 and neeextension +3, which indicates that the <oint that is

stretched has no influence on the <oint where +3 is

increased so long as the muscle crosses both <oints.

'imitations

he stud was limited insofar as the researchers did

not also measure changes in <oint +3 at <oints where

the hamstring muscles did not cross over the <oint,

such as the shoulder, in order to assess for the

presence of global effects.




8/18/2019 Scr Mar 2016 PDF


+omparison of effects of static, proprioceptive

neuromuscular facilitation and Mulligan stretching on

hip flexion range of motion) a randomi2ed controlled

trial, #y Aldrm, 02yurek, 'osun, D2er, 3 !elecek, in

&iology of %port 5/.7 "

Backgroundlexibilit is important for both athletes and for the

general population. lexibilit is defined as the abilit



individuals achieve greater <oint +3. or a more

detailed introduction to stretching, see the earlier

stud review.

OBJC!"#$ o compare the long-term effects of

static stretching #""', proprioceptive neuromuscular

facilitation #;>' stretching, and ulligan techni=ue

#' on hip flexion range of motion #as measured b

the passive straight-leg test using a goniometer' in

sub<ects with bilateral hamstring tightness.

%O%&'(!"O)$ 2: sub<ects with tight hamstrings #66males and $7 females', aged $&.4 5 &.7 ears, with a

passive straight-leg raise test result of Y:% degrees,

randoml allocated into 6 groupsG a "" group, a ;>

group, a group, or a no-stretching control #13>'

group.

")!*#)!"O)$ he sub<ects in the stretching

groups performed a 6-wee period of stretching under

the direct supervision or with the assistance of a

phsiotherapist, as appropriate.

What happened?

+omparison #etween stretching programs

he researchers found that hip flexion +3 increasedin all 7 stretching groups compared to the 13> group.

he also found that the ;> stretching and

groups produced greater increases in hip flexion +3

than the "" group. here was no difference between

the ;> stretching and groups.


he researchers concluded that "", ;> stretching,

and approaches are all able to improve hip flexion

+3, as measured b the passive straight-leg raise

test, in individuals with bilateral hamstring tightness.

he also concluded that ;> stretching and are

superior to "", although the are not different from

one another.

'imitations

he stud was limited as it was unclear how =uicl

the gains in hip flexion +3 would be lost after

finishing the program, and whether the gains achieved

b either ;> stretching or could be maintained b

"" afterwards.


http://biolsport.com/fulltxt.php?ICID=1194126

http://biolsport.com/fulltxt.php?ICID=1194126

8/18/2019 Scr Mar 2016 PDF


%tretching of active muscle elicits chronic changes in

multiple strain risk factors, #y <ay, 4ichmond, 'al#ot,

Mina, &aross, 3 &la2evich, in Medicine 3 %cience in

%ports 3 Exercise 5/.7"

Background

lexibilit is important for both athletes and for thegeneral population. lexibilit is defined as the abilit



individuals achieve greater <oint +3. or a more

detailed introduction to stretching, see the earlier

stud review.

OBJC!"#$ o assess the effects of static stretching

of an isometricall-contracting calf muscle on changes

in dorsiflexion +3, pea passive plantar-flexion <oint

moment #which is a measure of stretch tolerance',

area under the curve #A1' for passive plantar-flexion

<oint moment #which is a measure of energ storage',

slope of the passive plantar-flexion <oint moment

curve #which is a measure of muscle-tendon stiffness'and maximal voluntar isometric contraction #JI1'

plantar-flexion moment #measured with an isoinetic

dnamometer', and gastrocnemius medialis muscle

and Achilles tendon elongation #as measured using

ultrasound'.

%O%&'(!"O)$ &7 male collegiate soccer plaers,

aged $%.% 5 %.8 ears.

")!*#)!"O)$ "ub<ects performed stat ic

stretching while resisting the stretch b performing

isometric plantar-flexion contractions $ times per

wee, essentiall resulting in 4 sets of &$ maximal

isoinetic eccentric contractions at &% degreesFs.

What happened?

Effects on dynamometry measurements


dorsiflexion +3 #b &6.: 5 $.% degrees' and pea

passive plantar-flexion moment #b &72.$ 5 7%.$*'

after the training intervention. he change in +3 was

significantl correlated with the change in passive

plantar-flexion moment, which is a measure of stretch

tolerance #r L %.:$'. In addition, the researchers

observed a significant increase in the A1 for passive

plantar-flexion moment #b 7%$.2 5 84.)*', and in

the JI1 plantar-flexion moment #b 4&.7 5 :.4*'.

/owever, the did not find an change in the slope of

the passive plantar-flexion moment curve.

Effects on ultrasound measurements

he researchers observed significant increases in

tendon stiffness #b 7&.$ 5 4.%*' and a significant

decrease in passive muscle stiffness #b &6.2 5

6.7*'. his was noteworth, given the lac of an

change in muscle-tendon stiffness, as measured b

the slope of the passive plantar-flexion moment curve.

he researchers also identified no correlation between

the change in +3 and the changes in muscle or

tendon stiffness #r L %.&:M r L %.%)'.


he researchers concluded that active stretching #oreccentric training' produces substantial gains in <oint

+3, which are liel greater than those produced b

passive stretching. he also concluded that active

stretching produced changes in muscle-tendon

parameters that ma reduce in<ur ris, including

reducing muscle stiffness, increasing muscle strength,

increasing energ storage, and increasing +3.

'imitations

he stud was limited in that it is unclear whether the

changes observed are contributor to the beneficial

effects of eccentric training on sports in<ur ris.


8/18/2019 Scr Mar 2016 PDF


.1 days of #ed rest induces a decline in satellite cell

content and ro#ust atrophy of skeletal muscle fi#ers in

middle$aged adults, #y (rentson$ant2, English,

Paddon$Jones 3 @ry, in Journal of (pplied Physiology

5/.7"

BackgroundBed rest is a common model for studing disuse

atroph in humans. During periods of complete bed

rest, measurable levels of muscle loss occur =uicl, in

a matter of das. his muscle loss is attributed to a

reduction in the rate of muscle protein snthesis and

the development of anabolic resistance to food intae.

he stud of disuse atroph is important for several

purposes. uscle loss is a e problem for older

people, who fre=uentl suffer from sarcopeniaM it is

often seen in individuals undergoing rehabilitation

post-surger or in patients with a range of different

musculoseletal conditionsM and of course it is a

nown concern for astronauts undergoing long periods

of time in space. During bed rest, the lower bod

seems to be more affected than the upper bod. ore

specificall, those muscles in the lower bod that are

responsible for weight-bearing, such as the gluteus

maximus, =uadriceps, and calves are more maredl

affected than those that are onl involved in either

propulsion, such as the hamstrings, or balance, such

as the gluteus medius. In addition, during bed rest,

the loss of muscle cross-sectional area does not occur

similarl along the length of a muscle, but displas

regional atroph. "everal different resistance training

interventions have been found to be effective for

preventing disuse atroph during periods of bed rest,

including elastic resistance training, flwheel training,

standard resistance training, neuromuscular electrical

stimulation #>E"' training, and vibration training.

Additional protein intae, timed throughout the da, is

also ver commonl recommended, although few #if

an' studies have shown an benefit of consuming

extra protein in the absence of resistance training.

his underscores the importance of including some

sort of strength training intervention in an situation

in which individuals are liel to be unable to engage

in previousl habitual levels of activit, such as

increasing age, in<ur, surger, or illness.

OBJC!"#$ o assess the effect of &6 das of bed

rest on seletal muscle satellite cell content and fiber

tpe atroph #measured using vastus lateralis muscle

biopsies and performing immunohistochemistr to

assess mosin heav chain #/1' isoform expression,

fiber cross-sectional area, satellite cell and monuclear

content, and capillar densit', changes in maximal

aerobic capacit #as measured b a graded exercisetest on a ccle ergometer', =uadriceps strength #as

measured b unilateral nee extension pea tor=ue in

a dnamometer' and bod composition #using dual

energ N-ra absorptiometr DENAC scanning'.

%O%&'(!"O)$ : health, middle-aged adults #6

males and 7 females', aged 4&.% 5 %.2 ears.

")!*#)!"O)$ All sub<ects engaged in &6 das of

complete bed rest.

What happened?

Effects on muscle fi#ers

he researchers found that /1 tpe IIA fiberpercentage was significantl reduced and mean fiber

cross-sectional area was significantl decreased across

all fiber tpes #b $7.) 5 4.$*'. Additionall, the

found that satellite cell content was significantl

reduced #b 7).: 5 ).4*' and the noted that this

change in satellite cell content was significantl

correlated with the change in mean fiber cross-

sectional area #+$ L %.2%'. he also observed a small

but still significant reduction in monuclear content

occurred #b 4.7 5 &.6*'.

Effects on fitness and #ody composition

he researchers found that there was a significant

reduction in nee extension pea tor=ue #b &6 5

7>m' and a significant reduction in maximal aerobiccapacit #b &%*', which was significantl associated

with the decline #of $7.4 5 4.2*' in capillar densit

#+$ L %.48'. he researchers noted that sub<ects lost

2$: 5 $&:g in bod mass, but lean mass was reduced

b :&& 5 $78g, and fat mass increased b )6 5 &%%g.


he researchers concluded that there are rapid and

adverse changes in muscle fiber properties as a result

of bed rest lasting &6 das, including losses in lean

bod mass, reductions in /1 percentage, and large

decreases in mean fiber cross-sectional area and

satellite cell content, as well as small reductions in

monuclear content.

'imitations

he stud was limited insofar as it is unclear how

much phsical activit or exercise is necessar to

offset these adverse effects.


8/18/2019 Scr Mar 2016 PDF


Mirror training augments the cross$education of

strength and affects inhi#itory paths, #y >ult, !oodall,

'homas, %olnik, *orto#Ogyi, 3 *owatson, in Medicine

3 %cience in %ports 3 Exercise 5/.7 "

Background

;ossibl the most robust <ustification for the existenceof centrall-mediated factors driving changes in

strength following a resistance training program is the

presence of the cross-education effect. he cross-

education effect #also nown as the cross-transfer

effect or the cross-over effect' is the observation that

long-term resistance training of a limb can lead to

gains in voluntar strength in the contralateral limb.

his effect has been well-established, with a meta-

analsis of &7 randomi9ed controlled studies of

voluntar unilateral resistance training #using P4%*

of &+ and lasting P$ wees' showing contralateral

effects of resistance training of around an U)* #range

-7* ( $$*' increase on initial strength levels, or

U74* of the change in the ipsilateral limb. In order to

explain the cross-education effect, it has been

suggested that there exist central factors that are

altered with resistance training that affect both

ipsilateral and contralateral sides similarl, while the

ipsilateral limb also benefits from peripheral

#muscular' adaptations. 1urrentl, the underling

mechanisms for the cross-education effect are

unnown but ma include changes at cortical,

subcortical or spinal levels. he possibilit of changes

in man #but not all' peripheral factors has been

explored and re<ected. +elated to the cross-education

effect is the finding that imagined contractions can

lead to meaningful gains in strength. In a remarable

stud, it was found that left hand fifth digit

metacarpophalangeal abduction tor=ue increased after

a 6-wee period of resistance training in both the

conventionall-trained and imagined contractions

groups #b 7%* and $$*, respectivel' and that both

of these groups also displaed cross-education effects

to the right hand #b &6* and &%*, respectivel'. In

contrast, a control group displaed minimal changes in

measurements for both left and right hands. 3ther

researchers have also reported mared gains in

strength following imagined contractions. In addition,

there appears to be an additive effect of imagined

contractions and conventional resistance training,

particularl in respect of the lower bod.

OBJC!"#$ o assess whether mirror-viewing the

exercising hand during unilateral resistance training

would increase the si9e of the cross-education effect,

#as measured b the change in maximal voluntar

isometric contraction #JI1' force' and whether this

increase would be effected b changes in either

corticospinal excitabilit or short-interval intracortical

inhibition #as measured b using transcranial magneticstimulation "C'.

%O%&'(!"O)$ /ealth adults, randoml allocated

into either a mirror training #I+' group #&& sub<ects,

aged $4 5 6 ears' and no-mirror training #>3-I+'

group #&$ sub<ects, aged $8 5 8 ears'.

")!*#)!"O)$ All sub<ects performed &4 training

sessions over 7 wees, comprising 2 sets of )

repetitions with )%* of JI1, with 2% seconds of rest

betweens sets. he contractions were performed at $%

degreesFs and started with the wrist at $% degrees of

extension and ended with the wrist at $% degrees of

flexion, resulting in 6% degrees of range of motion

#+3'.

What happened?

Effects of mirror training on M9I+

he researchers found that the JI1 for wrist flexion

increased significantl #b :$*' across both I+ and

>3-I+ groups in the trained wrist. he also found

that there was a significant cross-education effect in

JI1 in the untrained wrist, and this was higher for

I+ #increaseG 2&*' than >3-I+ #increaseG 76*'.

Effects of mirror training on 'M% measures

he researchers found no evidence of changes in

corticospinal excitabilit in the untrained hand as a

result of the intervention in either group, but the didfind changes in short-interval intracortical inhibition

that differed between the two groups. "pecificall,

the found that I+ displaed different changes in

some of the " measurements compared to >3-I+,

including a reduction #b &4 ( &2*' in the

contralateral silent period duration, while >3-I+

showed an increase #b &$*'. "imilarl, inter-

hemispheric inhibition, measured from the trained to

untrained primar motor cortex, increased in I+ #b

&&*' but decreased in >3-I+ #b &4*' when

measured using the mirror in place.


he researchers concluded that viewing the exercisinglimb in a mirror increases the magnitude of the cross-

education effect, which seems to be produced b

greater changes in intracortical inhibition. his finding

ma have applications during rehabilitation.

'imitations


the wrist flexors and different results might be found

in other parts of the bod.




8/18/2019 Scr Mar 2016 PDF


M4I analyses show that <inesiotaping affects much

more than just the targeted superficial tissues and

causes heterogeneous deformations within the whole

lim#, #y Pamuk 3 Aucesoy, in Journal of &iomechanics

5/.6 "

BackgroundRinesiological taping is a popular treatment method in

which colorful elastic cotton strips with an acrlic

adhesive bacing are placed over various muscles in

order to appl tension when at rest and to increase

that tension when certain <oint actions are performed.

he designers of inesiological taping have suggested

that its use ma promote a range of therapeutic

ob<ectives, including a reduction in pain, an increase

in muscle tone, improved circulation, lmphatic

drainage, and a reduction of delaed onset of muscle

soreness. 1onse=uentl, clinicians often mae use of

inesiological taping methods to alter scapular

movement to treat shoulder impingement sndrome.

In this context, the primar function of the

inesiological tape is to provide support to the

scapular muscles and, through tension, to provide

proprioceptive feedbac in dnamic movements.

/owever, the literature in relation to the use of

inesiological taping to treat an musculoseletal

in<ur of the shoulder is inconsistent. "ome studies

have found that inesiological taping is able to alter

posture, increase shoulder movement range-of-motion

#+3' and reduce measures of pain. /owever, other

studies have found no change in pain or disabilit

scores. "uch differences ma have arisen because of

the use of different inesiological tape, taping

methods, sub<ects, shoulder in<uries, and tests. hus,

it is of great interest to clinicians to learn whether

there is an evidence for the use of inesiological

taping products and methods for the treatment of

musculoseletal in<ur, and it is also of great interest

for researchers to find out the mechanisms b which

such treatments might be effective.

OBJC!"#$ o characteri9e the mechanical effects of

inesiological taping in order to find out whether the

local deformations produced are in line with the tape

adhering direction, and whether these deformations

are limited to the directl targeted tissues #as

measured using magnetic resonance imaging #+I'

scans'.

%O%&'(!"O)$ 4 health female sub<ects, aged $4. 5

&.) ears.

")!*#)!"O)$ All sub<ects la prone on the +I

table with the left leg positioned with the anle at 8%

degrees and the nee at &4) 5 4 degrees. After taing

measurements with no inesiological tape in place, the

sub<ects were measured after being taped. aping

involved first placing the anle into dorsiflexion, before

appling the tape tightl along the tibialis anterior.

After this, the anle was moved into plantar-flexion

and held for 7% minutes. easurements were taen in

the taped condition.

What happened?

Effects of kinesiological taping in targeted tissues

he researchers reported that both lengthening and

shortening occurred superficiall along parts of the

sin in the directl targeted tissues, in anterior(

posterior directions. his caused parts of the sin to

be lifted or depressed. he researchers reported that

deeper, the tissues experienced shortening proximall

and lengthening distall.

Effects of kinesiological taping in non$targeted tissues

he researchers reported that there were apparent

deformations in variable magnitudes and directions for

all sub<ects in the non-targeted tissues, and the also

observed considerable inter-sub<ect variabilit in strainmagnitudes and directions.


he researchers concluded that the application of

inesiological taping produced local deformations in

line with the direction of the tape in onl one part of

the targeted region, but there were also deformations

in other directions in the targeted area, and there

were also si9able deformations in non-targeted areas,

along with substantial inter-sub<ect variabilit.

'imitations

he stud was limited insofar as it is unclear to what

extent the standardi9ation of the taping procedure

affected the results observed.




8/18/2019 Scr Mar 2016 PDF


'he role of descending modulation in manual therapy

and its analgesic implications a narrative review, #y

9igotsky 3 &ruhns, in Pain 4esearch and 'reatment

5/.6"

Background

an people mae use of massage therap for helpingwith musculoseletal pain. /owever, it is currentl

unclear how manual therap #including mofascial

release techni=ues' is able to bring about pain relief.

"everal mechanisms have been proposed, including

the release of endocrine hormones, inhibition of pain

feedbac, a reduction in inflammator signaling, and

direct effects on mofascial trigger points. In relation

to the potential mechanisms involving endocrine

hormones, it has been suggested that manual therap

causes a pain-relieving release of the endocrine

hormone oxtocin into the blood. Indeed, the direct,

sstemic administration of oxtocin appears to have

an analgesic effect on musculoseletal pain in

humans. In relation to potential mechanisms involving

inhibited pain feedbac, it has been suggested that

pain signaling could be altered secondar to the

activation of mechanoreceptors within muscle fibers

b the manual therap, which then leads to the

stimulation of large, primar afferent nerve fibers.

"ignals along these fast-conducting nerve fibers could

then interfere with pain signals transmitted along

slow-conducting, tertiar fibers and thereb produce

inhibition of pain feedbac in the spinal cord. his

model essentiall therefore builds on the extremel

popular pain gate control theor. In relation to

potential mechanisms involving the modulation of

inflammator signaling, it has been suggested that

manual therap could s=uee9e out inflammator

molecules, such as bradinins, from muscle tissues

and thereb reduce peripheral sensiti9ation and an

sensations of locali9ed tenderness. he potential

mechanism of mofascial trigger points is possibl the

most contentious mechanism. "ome researchers and

clinicians have suggested that mofascial trigger

points are tender spots in discrete, taut bands of

hardened muscle that produce local and referred pain.

It is therefore possible that where manual therap is

able to affect these tender spots, it ma be able to

relieve musculoseletal pain. /owever, it is unclear

precisel what mofascial trigger points are and how

the might be measured reliabl.

OBJC!"#$ o perform a narrative review of the role

of the descending pain modulation circuit in producing

the analgesic effects of manual therap. hese circuits

involve the activit of neurotransmitters, including

serotonin #4-/', vasopressin, oxtocin, adenosine,

endocannabinoids #E1' and endogenous opioids #E3',

which in turn act on structures such as the rostral

ventromedial medulla and the peria=ueductal gre,and thereb alter pain output.

What happened?

Effects of different types of manual therapy

he researchers identified that all tpes of manual

therap that have been studied appear to produce a

neurophsiological response involving the descending

pain modulation circuit. /owever, the also noted that

each tpe of manual therap ma displa different

mechanisms within that circuit. he observed that

the manipulative techni=ues, such as osteopathic

manipulative therap and spinal manipulation, displa

increases in E1 levels but not in oxtocin. obili9ation

techni=ues appear to be effective b means of

changes in E3 levels. In contrast, the found that

massage therap appears to generate a robust

oxtocin response.


he researchers concluded that the effects of manual

therap on pain seems to wor at least in part through

the descending pain modulation circuit, although

specific manual therap techni=ues might involve

slightl different mediating mechanisms.

'imitations

he stud was limited as it was a narrative reviewbased upon the opinions of the authors, and ma not

reflect the views of all researchers woring in the

same field.


8/18/2019 Scr Mar 2016 PDF


*ip muscle strength predicts non$contact anterior

cruciate ligament injury in male and female athletes a

prospective study, #y <hayam#ashi, !hoddosi,

%trau#, 3 Powers, in 'he (merican Journal of %ports

Medicine 5/.6 "

Background>on-contact anterior cruciate ligament #A1@' in<ur is

a ver common and =uite serious in<ur that occurs

fre=uentl in popular team sports, particularl those

which involve lateral pivoting, <ump landing or =uic

decelerations during sprint running. ;revious research

has identified that A1@ in<uries occur under two

predominant loading patternsG nee valgus collapse or

anterior tibial shear. While there are advocates and

adversaries of both mechanisms, studies have shown

that female athletes tend to displa greater nee

valgus than males and greater A1@ in<ur incidence.

+esearchers have also found that the tendenc to

displa greater nee valgus is a good predictor of A1@

in<ur ris. In general, the term Hvalgus refers to the

outward angling of the distal segment of a bone.

Where a <oint or a neighboring <oint has more than

one degree of freedom, this outward angling can

involve movements in transverse, sagittal or frontal

planes. Indeed, research indicates that nee valgus

#also called valgus collapse or medial nee

displacement' actuall arises as a result of hip <oint or

foot <oint actions. Rnee valgus in stance is seen in

con<unction with a combination of hip <oint adduction

and hip <oint internal rotation and occurs most

fre=uentl in positions of hip <oint flexion. Additionall,

foot pronation is commonl observed where nee

valgus occurs. he <oint actions at hip and foot appear

to lead to a medial displacement of the nee, which is

accompanied b nee <oint abduction and nee <oint

external rotation. Jarious explanations have been

proposed as causes of nee valgus. 3ne popular

proposal is that individuals have inade=uate hip

external rotator and hip abductor strength andFor

short, tight or overactive hip adductors andFor hip

internal rotations, leading to a tendenc for the hips to

move into hip adduction and hip internal rotation.

Another ver popular proposal is that anle

dorsiflexion mobilit is poor or that the lower leg

muscles #soleus, gastrocnemius, and anterior tibialis'

are short, tight or overactive, which prevents the tibia

and nee from moving forwards and causes the foot to

compensate b pronating. his inward foot movement

leads to mirrored movement at the hip #hip internalrotation and hip adduction' and therefore nee valgus.

wo less popular proposals are that a lac of either

vastus medialis obli=uus strength or a lac of medial

hamstrings strength leads to poor nee stabili9ation

and conse=uentl allows the nee to trac inward.

1hanges of direction during running #cutting' are

common in man popular team sports and the abilit

to perform them =uicl is a e attribute of

successful athletes. /owever, cutting maneuvers are

also associated with nee valgus and conse=uentl an

increased ris of non-contact A1@ in<ur.

OBJC!"#$ o perform a prospective cohort stud in

order to find out whether baseline hip external

rotation or hip abduction strength #as measured using

handheld dnamometr' can prospectivel predict the

ris of future non-contact A1@ in<ur in athletes #as

measured b using odds ratios' and to identif cut-offs

for increased ris #b reference to receiver operating

characteristic #+31' curves'.

%O%&'(!"O)$ 4%& competitive athletes #&7)

females, aged $%.8 5 6.$ earsM and 727 males, aged

$&.4 5 4.4 ears' participating in various sports.

")!*#)!"O)$ Before the start of the competitive

season, the researchers measured isometric hip

external rotation and hip abduction force bilaterall

using a handheld dnamometer. hen, in the sport

season, A1@ in<ur status was recorded, and the

nature of the in<ur was classified based on the

mechanism #non-contact vs. contact'.

What happened?

Incidence of (+ injury

he researchers recorded a total of &4 non-contact

A1@ in<uries #2 females and 8 males', which was an

annual incidence of 7.%* #$.4* for males and 6.7*

for females'.

*ip strength in injured and uninjured athletes

he researchers found that baseline hip external

rotation and hip abduction force levels normali9ed to

bodweight were both significantl lower in the in<ured

athletes, when measured pre-season, in comparison

compared with athletes who did not become in<ured.

"pecificall, hip external rotation force was &:.$ 5

$.8* of bodweight in in<ured athletes, but $$.& 5

4.)* in unin<ured athletes. "imilarl, hip abductionforce was 7%.) 5 ).6* of bodweight in in<ured

athletes, and 7:.) 5 :.2* in unin<ured athletes.

Predictive a#ility of hip strength for (+ injury

he researchers identified that the odds ratio for

increased ris of non-contact A1@ in<ur associated

with hip external rotation weaness was &.$7 times,

and for hip abduction weaness was &.&$ times. sing

+31 curves, the found that the cut-off point for hip

external rotation force was O$%.7* of bodweight

#87* sensitivit and 48* specificit', whereas for hip

abduction strength it was O74.6* of bodweight

#sensitivit of ):* and specificit of 24*'.


he researchers concluded that there are significant

relationships between baseline hip external rotation

and hip abduction strength, and future non-contact

A1@ in<ur. +educed hip external rotation and hip

abduction strength led to increased in<ur ris, in both

males and females.

'imitations

he stud was limited insofar as it is unclear whether

increasing hip external rotation andFor hip abduction

strength would reduce in<ur ris.




8/18/2019 Scr Mar 2016 PDF


'he vertical drop jump is a poor screening test for (+

injuries in female elite soccer and hand#all players a

prospect ive cohort study of -./ athletes, #y

<rosshaug, %teffen, <ristianslund, Nilstad, Mok,

Mykle#ust, 3 &ahr, in 'he (merican Journal of %ports

Medicine 5/.7 "

Background

>on-contact anterior cruciate ligament #A1@' in<ur is

a ver common and =uite serious in<ur that occurs

fre=uentl in popular team sports, particularl those

which involve lateral pivoting, <ump landing or =uic

decelerations during sprint running. or a detailed

introduction to A1@ in<ur, see the earlier stud

review.

OBJC!"#$ o identif whether an inematic and

inetic variables #as measured b a lined motion

capture and force plate set-up' measured during a

drop landing and subse=uent maximal <ump can

prospectivel predict the ris of future non-contact

A1@ in<ur #as measured b using odds ratios' and

identif cut-offs for increased ris #b reference to

receiver operating characteristic #+31' curves' in alarge cohort of >orwegian female elite soccer and

handball plaers.

%O%&'(!"O)$ :&% plaers, aged $& 5 6 ears.

")!*#)!"O)$ Before the start of the competitive

season, the researchers measured nee valgus angle

at initial ground contact, pea nee abduction net <oint

moment, pea nee flexion angle, pea vertical

ground-reaction force, and medial nee displacement

in the frontal plane during a drop landing from a 7%cm

box and a subse=uent maximal <ump.

What happened?

Incidence of (+ injury

he researchers recorded 6$ non-contact A1@ in<uries,

of which &$ were recorded in previousl A1@-in<ured

plaers.

Predictive a#ility of drop landing factors for (+ injury

he researchers identified that the onl factor that

was measured during the drop landings that was

associated with an increased ris of non-contact A1@

in<ur was medial nee displacement. "pecificall, in

the whole cohort of :&% sub<ects, medial nee

displacement was %.4cm greater in those who incurred

a new A1@ in<ur. In addition, it was &.%cm greater in

the group of 2: previousl-in<ured plaers. /owever,

when considering onl the plaers who had notincurred an A1@ in<ur previousl, there was no

difference. he researchers found that having a

greater medial nee displacement was associated with

an odds ratio of &.6% times, in respect of incurring a

new A1@ in<ur. /owever, using the +31 curve

analsis, the were not able to identif a single point

that maximi9ed sensitivit and specificit to an

acceptable level, which suggests that the use of

medial nee displacement as a screening tool is not

useful in this population.


he researchers concluded that there are ver limited

grounds for using inetic or inematic parametersmeasured during the drop landing and subse=uent

maximal <ump for the screening of A1@ in<ur ris.

'imitations

he stud was limited, as it is unclear whether an

programs that alter the parameters measured in the

current stud would have an effect on A1@ in<ur

ris.


http://ajs.sagepub.com/content/early/2016/02/08/0363546515625048.abstract

http://ajs.sagepub.com/content/early/2016/02/08/0363546515625048.abstract

8/18/2019 Scr Mar 2016 PDF


*ip joint pathology) relationship #etween patient

history, physical tests, and arthroscopy findings in

clinical practice, #y 'ijssen, +ingel, 9isser, *lmich, 3

Nijhuis‐van der %anden, in %candinavian Journal of

Medicine 3 %cience in %ports 5/.7 "

Backgroundemoroacetabular impingement #AI', which has also

been called hip impingement sndrome is a condition

in which the head of the femur moves in an abnormal

wa within the acetabulum of the pelvis or contacts

structures in such a wa that it causes damage.

nderling changes in hip <oint structure lead to a

reduction in hip clearance that results in impingement

during normal dail range of motion. here are several

forms of AI but the most common is dnamic

impingement of the hip, which can be caused b one

of several factors, including a cam lesion, a pincer

lesion, a combined cam and pincer lesion, proximal

femoral retroversion, or coxa vara. /owever, the onl

two tpes of dnamic impingement that are commonl

discussed in respect of AI are cam lesions and pincer

lesions. A cam lesion, which is short for Hcamshaft

lesion because of the wa that the bone growth

resembles a camshaft in this case, occurs where there

is an increase in the width of the femoral nec at the

femoral head-nec <unction. he reduced femoral

head-to-nec offset distance pushes the femur into

contact with the acetabulum earl in the arc of

internal rotation of the hip. A pincer lesion, occurs

where there is an excess of growth of the upper lip of

the acetabulum. A combined cam and pincer lesion

displas elements of both of these deformities. or

completeness, the other deformities are discussed

below. ;roximal femoral retroversion is where the

femoral nec contacts the labrum of the acetabulum of

the pelvis earlier in the arc of functional motion. 1oxa

vara, which is a deformit of the hip, in which the

angle between the ball and the shaft of the femur is

reduced to O&$% degrees. 1oxa vara fre=uentl results

in a limp and is often caused b in<ur but can also

occur when the bone of the femur is softer than it

should be and bends under the weight of the bod.

"ince there are man causes of AI, the underling

anatomical, biomechanical or environmental ris

factors are liel to be multifactorial and difficult to

ascertain. /owever, some researchers have identified

that there are certain anatomical factors that can

contribute to AI, including poor anterolateral

orientation, increased relative depth of the hipacetabulum, and offset abnormalities of the femoral

head-nec <unction. In addition, some researchers

have observed that hip strength is reduced in man

individuals who displa AI, although whether this

reduction is simpl a result of inhibition due to the

painful experience, disuse atroph or previous lac of

hip strength is unclear.

OBJC!"#$ o perform a retrospective cohort stud

in order to assess the accurac of patient histor and

phsical tests #both individuall and combined' for AI

and hip labral patholog #as confirmed b subse=uent

hip arthroscop'.

%O%&'(!"O)$ :: patients #:8 hips' who underwent

hip arthroscop between Kanuar $%&% and Kune $%&7b the same orthopedic surgeon.

")!*#)!"O)$ he range of phsical tests carried

out for each patient included the anterior impingement

test #AI', the lexion-Abduction-External rotation

#ABE+' test, the homas test, the +esisted "traight

@eg +aise #+-"@+' test, the "cour test, and the

it9gerald test #labral patholog onl'. ;atient histor

data recorded includedG the origin of complaint

traumatic vs. acuteC #labral patholog onl', groin as

main location of pain, clicing #labral patholog onl',

giving wa, locing, perceived stiffness, and perceived

mobilit restrictions.

What happened?

Physical tests and patient history

he researchers found that accurac of the phsical

tests was generall =uite poor, and onl the AI,

ABE+, and it9gerald tests had moderate-to-high

sensitivit levels #range %.:$ ( %.8&'. "imilarl, the

found that patient histor was also poor as an

accurate diagnostic aid, with onl groin as main

location of pain having a sensitivit P%.:. 1ombining

these factors produced good diagnostic accurac,

however, and using a model includingG groin as main

location of pain and a positive ABE+ test or a positive

AI and a positive ABE+ test displaed ver high

sensitivit #%.8:'.


he researchers concluded that combining patient

histor and phsical tests leads to a higher diagnostic

accurac for either AI andFor hip labral patholog

compared to an one individual test alone.

'imitations

he stud was limited as it onl included sub<ects who

ultimatel were found to have either AI andFor hip

labral patholog, and therefore it is impossible to now

what the specificit of the final model would be from

this data set. It is possible that the proposed

diagnostic has ver poor specificit #i.e. produces lotsof false negatives', b excluding too man patients.


http://onlinelibrary.wiley.com/doi/10.1111/sms.12651/full

http://onlinelibrary.wiley.com/doi/10.1111/sms.12651/full

8/18/2019 Scr Mar 2016 PDF


Q6R prevalence of a#normality on hip M4I in elite

academy level rug#y unionS a clinical and imaging

study of hip disorders, #y @arrell, Mc!rath, *ogan,

ogan, 8envir, 0+onnell, 3 :ilson, in Journal of

%cience and Medicine in %port 5/.7 "

Backgroundemoroacetabular impingement #AI', which has also

been called hip impingement sndrome is a condition

in which the head of the femur moves in an abnormal

wa within the acetabulum of the pelvis or contacts

structures in such a wa that it causes damage. or a

detailed introduction to AI, see the earlier stud

review.

OBJC!"#$ o perform a cross-sectional analsis to

compare the prevalence of hip disorders in elite level

academ rugb union plaers #using clinical tests as

well as radiological investigation' to active controls.

%O%&'(!"O)$ $% rugb plaers, aged $$.% 5 &.4

earsM and $% active controls, aged $&.7 5 &.: ears.

")!*#)!"O)$ he range of tests administered

included a patient histor =uestionnaire of 2 separate

sub-scales, assessing pain, smptoms, phsical

function in dail living, phsical function in sport and

recreation, participation in phsical activities, and hip

andFor groin-related =ualit of life #/A03"', as well as

phsical tests comprisingG active range of motion

#+3' of hip internal and external rotation, hip

flexion, and hip extension, and the homas and ABE+

tests. In addition, the rugb plaers underwent

magnetic resonance imaging #+I' scans of the hip in

axial obli=ue, sagittal and coronal planes.

What happened?

+linical tests and patient history

he researchers identified that the rugb plaers had

significantl and substantiall less active +3 than the

active controls for hip internal rotation, hip external

rotation, and hip extension #&%.% ( &$.:, $&.& ( $4.:,

and 6.$ ( 2.% degrees, respectivel'. In contrast,

there was no difference in respect of hip flexion +3.

he researchers identified that the rugb plaers

displaed significantl and substantiall less distance

on the ABE+ test #&4.$ ( &4.7cm' than the active

controls, but there was no difference in the homas

test. +egarding patient histor, onl one sub-scale on

the /A03" =uestionnaire differed between the rugb

plaers and active controls, and this was for the

smptoms, which was much higher in the athletes.

M4I findings in rug#y players

he researchers found a 84* prevalence of some sort

of abnormalit on +I #&8 of $% plaers', while )%*

of the athletes displaed labral patholog on +I.

here were some indications that the ABE+ test was

able to predict the presence of abnormal labral results

on the +I scans, as the ABE+ test scores for those

with normal and abnormal labral +Is were 7.)cm

different on the left, and 6.6cm different on the right.


he researchers concluded that the prevalence of hip

patholog is high in elite academ rugb plaers #84*of sub<ect measured', and the ABE+ test ma be

beneficial for identifing sub<ects prior to +I scans.

'imitations

he stud was limited as onl $% sub<ects were tested

in each group, and the active control group did not

receive +I scans. herefore, it is unclear how man

of this control group might have displaed pathological

readings.


http://www.sciencedirect.com/science/article/pii/S1440244016000281

http://www.sciencedirect.com/science/article/pii/S1440244016000281

8/18/2019 Scr Mar 2016 PDF


(n anatomic investigation of the 0#er test, #y :illett,

<eim, %hostrom, 3 omneth, in 'he (merican Journal

of %ports Medicine 5/.7 "

Background

Iliotibial band #IB' friction sndrome is a relativel

common overuse in<ur. IB friction sndrome seemsto be caused b the distal portion of the IB rubbing

against the lateral femoral epicondle during repeated

nee flexion and extension. herefore IB friction

sndrome is unsurprisingl fairl common in

endurance athletes, particularl long-distance runners,

militar recruits and cclists. Anatomicall, the IB is a

continuation of the tendinous part of the tensor fascia

lata and also connects to the gluteus maximus muscle.

Jarious ris factors have been suggested for IB

friction sndrome, including excessive exercise

volume, hip abductor weaness, and certain specific

biomechanical characteristics during running #e.g.

greater rear-foot invertor moments, and greater nee

internal rotation angle andFor greater hip adduction

angle during the stance phase of gait'. Jarious

rehabilitative interventions have been proposed for

IB friction sndrome, some of which are designed to

target the above identified biomechanical ris factors.

argeted interventions include resistance training for

strengthening the hip abductors and nee external

rotators, and stretching to improve the flexibilit of

the hip adductors and nee internal rotators.

ovement practice has also been suggested to

enhance the abilit to perform sagittal plane

movements without excessive hip adduction and nee

internal rotation.

OBJC!"#$ o assess the effects of transection of

the IB, gluteus medius and minimus muscles, and

hip <oint capsule of lightl embalmed cadavers on

3ber test results, to see whether transection of each

structure would lead to increased hip adduction range

of motion #+3' #as measured b an inclinometer

during the 3ber test #3' and also during the modified

3ber test 3C'.

%O%&'(!"O)$ &) lightl embalmed cadavers #&6

females and 6 males, mean age L:) ears, age range

L 64 ( 8: ears'.

")!*#)!"O)$ he cadavers were sub<ected to the

3 and 3, before and after the transection of the

IB, then the gluteus medius and minimus muscles,

and finall the hip <oint capsule. he 3 is performed

in the side-ling position with the leg to be tested

facing upwards. he examiner places the nee of the

upper leg into 8% degrees of flexion, before extending

the hip and placing the hip in abduction such that it is

line with the trun. he leg is then allowed to drop

into hip adduction as far as possible, while not movingin the sagittal or transverse planes. he 3 is

identical but the nee is maintained in full extension,

while the pelvis is stabili9ed manuall.

What happened?

Effects of transection

he researchers found that no significant changes in

hip adduction +3 were observed in either the 3 or

the 3 after IB transection. In contrast, the noted

significant changes after gluteus medius and minimus

transection, and after hip <oint capsule transection. or

the 3, the transection of the gluteal musculature

produced a change from ($.$% 5 2.7& to 2.4% 5 2.)2

degrees, and the transection of the hip <oint capsule

produced a further increase from 2.4% 5 2.)2 to 8.47

5 2.4& degrees. or the 3, the transection of the

gluteal musculature produced a change from 7.77 5

4.6% to &&.$% 5 7.8$ degrees, and the transection of

the hip <oint capsule produced a further increase from

&&.$% 5 7.8$ to &7.$% 5 6.8) degrees.


he researchers concluded that these findings refute

the hpothesis that the IB limits hip adduction during

either the 3 or 3, and thereb =uestion the

validit of either test as a measurement of IB

tightness. +ather the tests appear to measure the

tightness of the gluteus medius and minimus muscles

as well as the hip <oint capsule.

'imitations

he stud was performed in cadavers, and differences

between dead and living sub<ects ma introduce

confounding factors into the analsis.





8/18/2019 Scr Mar 2016 PDF


(ngry posture, #y 4osario, 8iogenes, Mattei, 3 eite,

in Journal of &odywork 3 Movement 'herapies 5/.7"

Background

;schological research has revealed that human

beings communicate ver extensivel non-verball.

Indeed, some researchers maintain that the largerpart of our normal communications are made non-

verball. In particular emotions of all tpes are

communicated using various non-verbal signals,

including tone of voice, volume of voice, posture,

speed and tpe of movements, and proximit to

others. an studies have explored how these

emotions #including sadness and anger' are

communicated between humans via non-verbal

signals, including bod language. /owever, most

studies have focused on non-verbal signals that are

produced in con<unction with speech, or at the point of

an obvious communication, rather than as an ongoing

bacground signal. +ecentl, however, some studies

have found that there is a connection between

habitual standing posture and general mood states

over a longer period of time. or example, one stud

has reported a clear and significant correlation

between the tpical level of sadness and the degree to

which the shoulders are anteriorl displaced. /owever,

the same stud did not find an correlation between

current sadness measures and the same measure of

shoulder position. "uch research has important

implications for the various postural theories of

musculoseletal pain sndromes, as where certain

postures are used to communicate adverse mood

states this confounds the potential connections

between posture and pain because of the underling

pschosocial factors.

OBJC!"#$ o identif if there is an relationship #as

measured using ;earson?s r to assess correlations'

between sub<ective current anger and sub<ective

tpical anger #as measured b a visual analog scale

JA"C' and bod posture #as measured b digital

photograph', in the absence of an neurological,

pschiatric or musculoseletal disorders.

%O%&'(!"O)$ $) females, aged between $% ( 78

ears.

")!*#)!"O)$ he researchers used a digital

camera to measure the following postural parameters

in =uiet standingG height of the hands, angle of tales,

forward head, tilting of the head, rotation of the head,

elevation of the shoulders, shoulder slope, protrusion

of the shoulder, nee hperextension, valgus nee,

and valgus anle. he used a JA" to measure both

current and tpical anger, with the scale ranging from

Hno anger at all to the extreme left and Hutter rage

at the far right, numbered from % to &% points.

What happened?

+orrelations #etween posture and current anger

he researchers found a correlation between current

anger and inclination of the shoulders #r L %.6&',

protrusion of the head #r L %.72', and hperextension

of the nees #r L%.72'

+orrelations #etween posture and typical anger

he researchers also found a correlation between

tpical anger and shoulder elevation #r L %.7$' and

nee hperextension #r L %.7)'.


he researchers concluded that there are associations

between current anger and shoulder inclination, nee

hperextension, and protrusion of the head. In

addition, the found associations between usual anger,

shoulder elevation, and nee hperextension.

'imitations

he stud was limited b the use of the sub<ective

measures of anger, and the self-report of tpical

anger. Different results might be obtained if the self-

report of tpical anger had been performed dail over

the preceding few wees prior to the investigation.

scr mar 2016 pdf

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