edexcel a level physical education a 9536 next previous unit 6 a.3.1 edexcel examinations a level...

Unit 6 A.3.1

Edexcel A Level Physical Education A 9536

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Edexcel ExaminationsA Level Physical Education

A 9536

Unit 6 : Section Apart 3

Scientific Principles of Exercise and Performance

Unit 6 A.3.2


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INDEX20 - SHORT-TERM RESPONSE TO AEROBIC ACTIVITY

THE AEROBIC SYSTEM / AT REST21 - SHORT-TERM RESPONSE TO AEROBIC ACTIVITY THE AEROBIC SYSTEM22 - SHORT-TERM EFFECTS OF AEROBIC EXERCISE - a-vO2

diff23 - SHORT-TERM METABOLIC RESPONSE TO AEROBIC

ACTIVITY24 - LONG-TERM VASCULAR ADAPTATIONS TO AEROBIC

TRAINING25 - LONG-TERM METABOLIC ADAPTATIONS TO AEROBIC

TRAINING26 - LONG-TERM NEUROMUSCULAR ADAPTATIONS TO

AEROBIC TRAINING27 - FOOD FUEL UTILISATION DURING AEROBIC EXERCISE

GLYCOGEN SPARING28 - ONSET OF BLOOD LACTATE ACCUMULATION (OBLA) LONG-TERM ADAPTATIONS OF OBLA TO AEROBIC

TRAINING29 - CELLULAR ADAPTATION PRODUCED BY AEROBIC

TRAINING30 - GENERAL LONG-TERM ADAPTATIONS PRODUCED BY

TRAINING INDIVIDUAL RESPONSE / SWEATING / REGRESSION31 - GENERAL LONG-TERM CELLULAR ADAPTATIONS TO

TRAINING NEURAL / MUSCLE CELLS

Index

3 - ERGOGENIC AIDS4 - ERGOGENIC AIDS

CARBOLOADING5 - ERGOGENIC AIDS CREATINE / GLUTAMINE / CAFFEINE / ALCOHOL6 - ERGOGENIC AIDS - BLOOD DOPING / rEPO7 - ERGOGENIC AIDS ALTITUDE TRAINING - PSYCHOLOGICAL / THERAPIES8 - ERGOGENIC AIDS - MECHANICAL9 - ERGOGENIC AIDS AMPHETAMINES / BETA BLOCKERS / HGH ANABOLIC STEROIDS10 - RESPONSES TO TRAINING11 - THE ENERGY CONTINUUM

VARIATION IN CONTRIBUTION OF ENERGY SYSTEMS12 - HIGH INTENSITY EXERCISE

SHORT-TERM RESPONSES13 - THE LACTIC ACID SYSTEM

EFFECTS OF CONTINUED HIGH INTENSITY EXERCISE14 - THE LACTIC ACID SYSTEM

OBLA15 - FOOD FUEL USAGE DURING HIGH INTENSITY EXERCISE

DURING HIGH INTENSITY EXERCISE16 - LONG-TERM ADAPTATIONS TO HIGH INTENSITY

TRAINING ANAEROBIC17 - LONG-TERM NEUROMUSCULAR ADAPTATIONS

PRODUCED BY STRENGTH (ANAEROBIC) TRAINING MUSCLE CELL RESPONSE18 - LONG-TERM NEUROMUSCULAR ADAPTATIONS

PRODUCED BY STRENGTH(ANAEROBIC) TRAINING19 - LONG-TERM NEUROMUSCULAR ADAPTATIONS

PRODUCED BY STRENGTH (ANAEROBIC) TRAINING NEURAL / CONNECTIVE TISSUE RESPONSES

Unit 6 A.3.3


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ERGOGENIC AIDS

Fatigue and Recovery Process

ER GO GEN I C A I DStherapies

m echanical

psycho logical

nutrition

legal physio logical

illegal physio logical

illegal pharm aceutical

Unit 6 A.3.4


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ERGOGENIC AIDSFatigue and Recovery Process

NUTRITIONALDIETARY MANIPULATIONCARBOLOADING• aims to raise muscle glycogen stores above their normal resting levels• prior to endurance competitions with over 90 minutes continuous

activity• suitable for activities with low anaerobic and high aerobic components

• based on :• depletion - prolonged exercise to reduce levels of liver and muscle

glycogen stores - at least seven days before event• repletion - a high CHO diet in the period (three to four days) before

activity• combined with light exercise or rest

• also suitable for activities lasting 15 - 20 minutes• with a two day high CHO diet beforehand (see previous slides)

ERGOGENIC AID• any substance or method

which enhances performance

Unit 6 A.3.5


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NUTRITIONALDIETARY MANIPULATIONCREATINE SUPPLEMENTATION• creatine is a substance found in skeletal muscle• stored as phosphocreatine (PC)• supplementation increases PC levels to enhance the ATP-PC system of

ATP resynthesis• thereby delaying the alactic / lactic thresholdGLUTAMINE• is an amino acid forming part of skeletal muscle and immune cells• supplementation after exercise therefore reinforces the immune system

and reduces the risk of infectionCAFFEINE• stimulates the CNS but acts as a diuretic - this can lead to dehydration• illegal in large quantitiesALCOHOL• a relaxant in quite small quantities• absorbed into the body as an alternative to water therefore causes

dehydration• quite small quantities of alcohol can cause a drastic loss of performance

Unit 6 A.3.6


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ILLEGAL PHYSIOLOGICALBLOOD DOPING• involves the removal of athlete’s own blood which is then stored• the athlete’s body then remanufactures blood to replace that

taken• then the stored blood is reinfused• this temporarily increases red blood cell count (polycythemia)• problem of mis-matching can lead to a transfusion reaction

• increases VO2max and hence energy delivery to enhance aerobic performances

rEPO• involves infusion of hormone recombinant erythropoietin 6

weeks prior to major event• stimulating erythrocytes (up to 10% more) - red blood cells

• increases VO2max and hence energy delivery to enhance aerobic performances

• but elevates red blood cell production that can reach toxic life-threatening levels

• other risks are blood clots, strokes / coronary thrombosis, very low resting heart rates

Unit 6 A.3.7


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LEGAL PHYSIOLOGICALALTITUDE TRAINING• a predominantly endurance-based exercise programme used by elite endurance

athletes from a range of sports• consisting of 2 visits of at least two weeks duration per visit, to altitude (normally

between 1800-3000 metres)• second visit just prior to major competition• training at altitude uses the fact that the body will create more haemoglobin • to compensate for the reduction in oxygen available• benefits : reversible physiological adaptations

– increased Hb concentration– increases in myoglobin mitochondria and oxidative enzymes

• hence on return to sea level we have an increased VO2max and tissue cell respiration leading to enhanced aerobic performance

• risks : hypoxia, altitude sickness

PSYCHOLOGICAL• imagery / hypnosis stimulate mental rehearsal of relevant skills • by activating neural pathways that reinforce skill

THERAPIES• physiotherapy / acupuncture / herbal medicines used in injury treatment• reduce muscle soreness and aid recovery of local damaged tissue

Unit 6 A.3.8


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MECHANICALNASAL STRIPS• use of sticky plaster placed over bridge of nose to enlarge

nasal cavity• enables easier breathing

SPECIALIST EQUIPMENT• carbon fibre bike frames are lighter and

aerodynamically more efficient• specialist training machines

– concept II ergo rower– swimming ergo– flumes for rowing / swimming / canoeing– treadmill

SPECIALIST CLOTHING• cycling helmets and lycra sports clothing reduces air

resistance• Denise Lewis one shoulder javelin suit, bench press and

squatting suits– provide extra force in required directions

Unit 6 A.3.9


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ERGOGENIC AIDS

Fatigue and Recovery Process

ILLEGAL PHARMACEUTICALAMPHETAMINES• act as CNS stimulants to increase arousal levels

BETA BLOCKERS • reduce HR and BP thereby reducing tension, but can lead to

heart failure

HUMAN GROWTH HORMONE (HGH) • stimulates bone growth and increased lean body mass• give artificial increased strength / power outputs

ANABOLIC STEROIDS • increase lean body mass, but reduce natural secretions of

gonadotrophins • females acquire masculine features such as facial and body

hair and deep voices• give artificial increased strength / power outputs

Unit 6 A.3.10


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RESPONSES TO TRAININGShort / Long-term Responses

SHOR T-TER MR ESPONSES TO

TR AI N I NG

m etabolicresponse

2 secondsATP

7-9 secondsATP/ PC

45 secondslactic acid

indefiniteaerobic

LONG-TER MAD APTATI ONSTO TR AI N I NG

m etabolicresponse

HIGH INTENSITYSHORT DURATION

LOW INTENSITY LONG DURATION

Unit 6 A.3.11


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THE ENERGY CONTINUUMVARIATION IN CONTRIBUTION OF ENERGY SYSTEMS

• as time progresses during intense exercise, the following chart shows the contribution of the different energy systems to the resynthesis of ATP

Short / Long-term Responses

Unit 6 A.3.12


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HIGH INTENSITY EXERCISESHORT-TERM RESPONSESATP muscle stores are depleted

within 2 secondsATP/PC system• rising ADP levels stimulate

the breakdown of PC stores • in coupled reaction with ADP

pool• peak anaerobic power

attained within first 5 seconds of flat-out exercise

• depletion of PC occurs between 7-9 seconds


• on the graph, the ATP level is maintained (after an initial small drop) then falls as PC is used up

• by the energy from PC being used to resynthesise ATP

• so PC levels fall rapidly

• capacity to maintain ATP production at this point depends on lactic acid system

Unit 6 A.3.13


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THE LACTIC ACID SYSTEM

EFFECTS OF CONTINUED HIGH INTENSITY EXERCISE• glycolysis or incomplete breakdown of glucose molecule• small energy yield of 2ATP per glucose molecule• dominant between 10-60 seconds

• increased lactic acid production to and beyond lactic threshold (OBLA) see next three slides

• reduced pH inhibits glycolytic enzymes GPP, PFK and LDH• increased muscle fatigue and pain• delayed onset of muscle soreness (DOMS) occurring

24-48 hours after exercise• particularly following plyometric (eccentric) training• produces a marked reduction in physical performance•

• capacity to maintain ATP production then begins to rely on the aerobic system


Unit 6 A.3.14


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THE LACTIC ACID SYSTEM

OBLA• as work intensity increases lactic

acid starts to accumulate above resting values

• at a certain point this produces muscle fatigue and pain

• the resultant low pH inhibits enzyme action and cross-bridge formation

• hence muscle action is inhibited• physical performance deteriorates


• OBLA depends on the level of training

• and lies between 2 and 4 mmol l-1

Unit 6 A.3.15


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FOOD FUEL USAGE DURING HIGH INTENSITY EXERCISE

DURING HIGH INTENSITY EXERCISE


Unit 6 A.3.16


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LONG-TERM ADAPTATIONS TO HIGH INTENSITY TRAINING


LONG-TERM ADAPTATIONS TO AN ANAEROBIC TRAINING PROGRAMME

• increases in stores of ATP and PC

• and amounts of anaerobic enzymes such as creatine kinase

• result in more energy to be available more rapidly

• and therefore increases in maximum possible peak power

• and a delay in the ATP/PC to lactic threshold

Unit 6 A.3.17


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LONG-TERM NEUROMUSCULAR ADAPTATIONS PRODUCED BY STRENGTH (ANAEROBIC) TRAINING


MUSCLE CELL ADAPTATIONS (FAST TWITCH FIBRES)• muscle hypertrophy (of fast twitch fibres) increases cross sectional area

of existing fibres by increasing :– number of myofibrils within each muscle cell– sarcoplasmic volume– contractile proteins : actin and myosin– mass of fast twitch fibres– number of fast twitch fibres (hyperplasia)

• hence % of type II increases and % of type I decreases• increase in muscle cell stores such as ATP, PC, and glycogen• increase in anaerobic enzymes such as creatine kinase (CK), PFK, GPP, and

LDH• increase toleration of lactate in fast twitch fibres• improved ability to remove lactate from muscle cell into blood• therefore enhancement of alactic / lactate and lactate / aerobic thresholds -

delay in OBLA• hence improved capacities of alactic and lactic acid systems to

resynthesise ATP• and ability to maintain maximal power output for longer• decrease in DOMS, particularly following eccentric training

Unit 6 A.3.18


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ATPCP

glycogenglycolytic enzymes

lactic acid

ATPCP

glycogenglycolytic enzymes

lactic acid

AFTER SEVERAL WEEKS OF STRENGTH (ANAEROBIC) TRAINING

= SLOW TWITCH MUSCLE FIBRE (type I) (starts small gets smaller)= FAST TWITCH MUSCLE FIBRE (type II) (starts big gets bigger)

MUSCLE CELLBEFORE TRAINING

LONG-TERM NEUROMUSCULAR ADAPTATIONS PRODUCED BY STRENGTH(ANAEROBIC) TRAINING

Unit 6 A.3.19


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LONG-TERM NEUROMUSCULAR ADAPTATIONS PRODUCED BY STRENGTH (ANAEROBIC) TRAINING


NEURAL ADAPTIVE RESPONSE• increased rate of response of CNS (Central Nervous

System)• recruitment of additional fast twitch fibre motor units• improved coordination of fast twitch fibre motor

units• toughening of proprioceptors so that more force is

required to stimulate inhibitory signals

CONNECTIVE TISSUE ADAPTATIONS• increase in thickness and strength of tendons• increased flexibility of ligaments• thickening and improved elasticity of cartilage• strengthening of bone tissue due to increased

depositing of calcium• therefore reduced risk of injury

Unit 6 A.3.20


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SHORT-TERM RESPONSE TO AEROBIC ACTIVITY

THE AEROBIC SYSTEM• unlimited supply of energy• to sustain the forces needed during low

intensity and long duration activity

AT REST• ATP utilisation is slow• a mixture of fats and carbohydrates is

used to resynthesise ATP

• the graph shows that initially CHO is the major supplier of chemical energy


• the longer the exercise the greater utilisation of fats

• as muscle and liver glycogen stores become depleted

Unit 6 A.3.21


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SHORT-TERM RESPONSE TO AEROBIC ACTIVITY

THE AEROBIC SYSTEM• requires CHO in the form of

glucose• which is derived from

glycogen stored in muscle cells (mostly ST slow twitch)

• or in the liver• the graph shows how the rate

of usage of muscle glycogen is high during the first 30 minutes of steady exercise


• the amount of glycogen remaining

• depends on the intensity and duration of the exercise

• and the CHO content of diet prior to exercise

• once the glycogen is used it may take days to fully replenish

• again depending on diet

Unit 6 A.3.22


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SHORT-TERM EFFECTS OF AEROBIC EXERCISE


a-vO2 diff

• note that the blood draining from working muscle tissue may be almost completely depleted of oxygen

• however, the mixed venous return would still have around 5ml/dl because it is a mixture of blood from the working muscles and less active parts of the body combined

a-vO2 diff - AT REST

venule capillary arteriole

blood flow15ml O2

per 100ml blood20ml O2

per 100ml blooda-vO2 diff = 5ml

per 100ml blood

a-vO2 diff - DURING INTENSE EXERCISE


blood flow5ml O2



per 100ml blood

Unit 6 A.3.23


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SHORT-TERM METABOLIC RESPONSE TO AEROBIC ACTIVITY

METABOLIC RESPONSE


• oxygen consumption or VO2 reflects the metabolic activity of the body and increases linearly with work

• then it levels out as the pulmonary system reaches its maximum capacity for rate of absorption of oxygen

• examples :Activity VO2 ml/kg/min-1

At rest 3.5Walking 10Jogging 20

At VO2max 55

Unit 6 A.3.24


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LONG-TERM VASCULAR ADAPTATIONS TO AEROBIC TRAINING


VASCULAR ADAPTATIONS

• arteriovenous oxygen difference (a-vO2diff)

• a-vO2diff increases with training particularly at maximal workloads

• due to increased oxygen extraction by active tissue• caused by :

– more effective blood shunting– improved capillarisation of trained muscle – more efficient use of existing capillaries

a-vO2 diff - AT REST


blood flow15ml O2



per 100ml blood

a-vO2 diff - DURING INTENSE EXERCISE


blood flow5ml O2



per 100ml blood

Unit 6 A.3.25


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LONG-TERM METABOLIC ADAPTATIONS TO AEROBIC TRAINING


LONG-TERM METABOLIC ADAPTIVE RESPONSE

• example data of VO2max ml/kg-1min-1

• gender and training differences

Group Age Male Female

Non athletes 10-19 47-56 38-4620-29 43-52 33-42

Basketball 18-30 40-60 43-60 Cross-country skiing 20-28 65-94 60-

75 Gymnastics 18-22 52-58 36-50 Rowing 20-35 60-72 58-65 Runners 18-39 60-85 50-75

• note that in the above data untrained females have much lower VO2max values (between 20-25%) compared with untrained males

• whereas endurance-trained females have VO2max values much closer to those of endurance-trained males (about 10% lower)

Unit 6 A.3.26


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LONG-TERM NEUROMUSCULAR ADAPTATIONS TO AEROBIC TRAINING


ADAPTATIONS PRODUCED BY AEROBIC TRAINING

MUSCLE CELL ADAPTATIONS• more myoglobin is created in muscle cells• more and bigger mitochondria in muscle cells• increased oxidative enzymes glycogen phosphorylase,

phosphofructokinase, lipoprotein lipase• hence increased activity of Kreb’s cycle and electron transport chain• and increase in stores and utilisation of fat• increase in stores of glycogen in muscle• which enables more fuel to be available for aerobic work

• conversion of type IIb to type IIa fibres

NEURAL ADAPTATIONS• better recruitment of slow twitch fibre motor units making muscle

usage more efficient

Unit 6 A.3.27


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FOOD FUEL UTILISATION DURING AEROBIC EXERCISEShort / Long-term Responses

GLYCOGEN SPARING AS A LONG-TERM ADAPTATION TO AEROBIC TRAINING

• for the person who has undertaken sustained aerobic training

• an adaptation is produced where fats are used earlier on in exercise

• thus conserving glycogen stores (respiratory exchange ratio (RER) indicates greater use of fats)

• the graph shows a higher proportion of fats utilised by the trained person

• thereby releasing CHO for higher intensity work

Unit 6 A.3.28


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ONSET OF BLOOD LACTATE ACCUMULATION (OBLA)

LONG-TERM ADAPTATIONS OF OBLA TO AEROBIC TRAINING

• this point governs the lactic aerobic threshold

• trained athletes begin OBLA at higher work intensities

• and higher values of VO2max than untrained people


Unit 6 A.3.29


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CELLULAR ADAPTATION PRODUCED BY AEROBIC TRAINING


glycogenfats

oxygen uptake

glycogenfats

oxygen uptake

AFTER SEVERAL WEEKS OF AEROBIC TRAINING

= SLOW TWITCH MUSCLE FIBRE (type I)= FAST TWITCH MUSCLE FIBRE (type II) (do not increase in size)

BEFORE TRAINING

Unit 6 A.3.30


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GENERAL LONG-TERM ADAPTATIONS PRODUCED BY TRAINING


INDIVIDUAL RESPONSE• adaptive response depends on individual

– fitness– cultural differences– gender– psychological factors– maturation

SWEATING• improved ability to sweat• more efficient heat loss

REGRESSION• when training stops, adaptive responses cease• the longer the training the more stable the adaptation

Unit 6 A.3.31


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GENERAL LONG-TERM CELLULAR ADAPTATIONS TO TRAINING

NEURAL CELLS• increased rate of firing of CNS, therefore increased

stimulation of motor units• therefore increased recruitment of FT and ST motor

units

MUSCLE CELLS• increased rate of cellular respiration means

increased O2 consumption

• or increased use of energy stores causes a decrease in PC and glycogen in ST and FT fibres

• decrease in triglycerides, oxymyoglobin stores

• increase in ADPs , Mg++, Ca++

• reduced pH inhibits cellular enzymes

• resulting in a general increase in muscle fatigue as muscular performance reduces


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