Download - Flexibility (Testing and Training)
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Flexibility (Testing and Training)
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Outline
Definitions of Flexibility Warm up vs Stretching Factors that influence Range Of Motion (ROM) Physiology and Biomechanics of Flexibility Assessment of Flexibility Benefits of Flexibility Flexibility program variables
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Definitions of Flexibility “ability to be bent, pliable” The New Shorter Oxford
English Dictionary (1993) Functional ability of a joint to move through its full
range of motion (ROM) (ACSM 2010) Functional ability - movement without incurring pain or a
limit to performance “The ability of a joint to move through its full range of
motion” (Brooks et al. 2000). There is little agreement about the definition of “normal”
flexibility. Optimum flexibility is hard to assess, and varies with
sport. More ROM is not necessarily better. Inadequate flexibility can decrease performance of
activities of daily living as well as some sports.
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Further Definitions
Flexibility refers to the extensibility of periarticular tissues to allow normal or physiological motion.
Laxity refers to the stability of a joint (Saal, 1987). Excessive joint laxity can be the result of
injury or heredity condition. Hypermobility refers to a range of motion in
excess of the accepted normal motion in most of the joints (Alter, 1996).
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Types of Flexibility
Static flexibility: ROM about a joint with no emphasis on speed.
Ballistic flexibility: usually associated with bobbing or bouncing motion.
Dynamic (functional) flexibility: ability to use ROM in the performance of a physical activity.
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Warm up Warm up prepares athletes for training or competition
May reduce the risk of injury and improve performance Increase muscle temperature, core temperature, and blood flow Impact on performance;
Faster muscle contraction and relaxation Increased rate of force development Inc muscle strength and power Lowers viscosity of muscle Improved O2 delivery (Bohr effect - temperature) Increased blood flow to active muscle Increased rate of metabolic reactions
NSCA - Essentials of Strength Training and Conditioning 2008
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Components of a Warm up Warm up should be gradually progressive without causing
fatigue General - 5 to 10 minutes low intensity
My be sport specific (jogging / ball dribbling) Raise HR, ventilation, blood flow, deep muscle temperature and
reduce viscosity Specific - 10 minutes
Dynamic stretching (mobility drills) - sport specific movements (examples near end of lecture)
Progressively increase intensity - sprint drills, jumping High intensity dynamic exercises may facilitate subsequent
performance Static Stretching in warm up may decrease subsequent
performance Decreased force, power, running speed, reaction and movement
time, endurance
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Factors that Influence ROM Range of Motion (ROM) is joint specific, and results from
a combination of factors; including adequate warm-up Structure of Joint - (47%)
Determines degree of freedom of movement Hinge vs ball and socket joint
Rigidity of Ligaments (10%) Help stabilize and protect joints from excessive motion during
dynamic movements Restrict ROM and offer support at end of ROM
Extensibility of periarticular tissues - muscle and tendon (41%) Component that can be modified most significantly and
influenced by flexibility training Length of muscle and level of neurological innervation in
muscle being stretched
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Other influences on Flexibility Nervous system activity
Sudden stretch of a muscle stimulates muscle spindle and reflex contraction
Important for proprioception and controlling muscle length
Slow static stretches, spindle activity increases for about 10 sec then diminishes greatly This can also help alleviate muscle cramps
Intracapsular structures articular cartilage and synovial membranes facilitate
smoothness of movement while maintaining integrity of joint
Soft tissue compression of soft tissue by adjacent segments
contributes to termination of ROM Eg obese or very heavy musculature
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Limits due to Muscle Structure
Contractile Components of Muscle Sacromere (S) resting length 2.30mm Maximum extensibility 3.50mm (150%) Hence increased extensibility occurs by an increase in
the # of sarcomeres in series Improper Muscle Balance
Stretch short muscle (flexibility assessment) Strengthen weak muscle (strength assessment)
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Total Length-Tension CurveText Fig.3-18
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Limits due to Connective Tissue Connective tissue surrounds muscle fibers (fascia), and in
a major component of tendons and ligaments Collagen - strong and flexible but resist stretching Elastin - thin with high degree of elasticity
ability to stretch and recoil Stress / Strain curves
Fig 54.1 ACSM Linear - elastic region - will return to original shape non linear - plastic deformation and repair by fibroblasts
Sustained stretch of 30-90 seconds in necessary to get beyond elastic recoil properties of skeletal muscle and stimulate fiber reorganization
Goal of flexibility training program is to induce gradual deformation of connective tissue - stimulate repair and greater ROM
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Limits due to Connective Tissue Aging
Joints become less stable and less mobile Degradation of collagen, joint surface, and
decreased viscosity of synovial fluid increases collagens diameter and more collagen
cross-links Stiffness and inflexibility common with aging Sometimes difficult to separate aging from wear
and tear to joints Flexibility training can induce remarkable
improvements in aged population if no permanent damage to joint structure has occurred
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Assessment of Flexibility Measurement made visually or with special instrumentation Utilize active or passive movement of subject Precision in assessment techniques enhances both accuracy
and reliability Proper identification of landmarks Consistency in the inclusion or exclusion of a warm-up is important
for reliability Starting position and body position for measurements
Visual assessment (qualitative) - inaccurate for both spinal and extremity evaluation but useful for fitness screening, group evaluation and field testing - we
will do several visual assessments Degree of completion of assessment in standard position -
see lab manual Eg - Finger tips touching (or not) with combined bilateral
rotation of shoulders and elbow flexion
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Quantitative Assessment of Flexibility Measurement Devices Indirect - linear - sit and reach apparatus,
anthropometer, tape measure Direct - ROM in degrees - Goniometer /
Leighton Flexometer Goniometer is inexpensive and portable Kin 142 no longer uses Flexometer
We will perform one measurement with Flexometer for familiarity and one with Goniometer for review
Dynamic Flexibility can be measured with stop motion video with reflective markers on bony landmarks Similar to motion capture for video games and animation
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Quantitative Measurements Eg. Sit-reach (modified by Hoeger) - accounts
for influence of length of body segments necessary when doing indirect measures First measure taken with back touching wall Second measurement with truck flexion Difference provides data for comparison
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Benefits of Flexibility Training Increased physical performance Decreased risk of injury (but not due to inclusion as
part of a warm-up) Increased blood supply and nutrients to joint
structure Increased quality and quantity of joint synovial fluid Increased muscular coordination Improved muscular balance, posture and postural
awareness Decreased muscle viscosity, causing contractions to
be easier and smoother
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Benefits of Flexibility (cont) Reduced muscular soreness Promotion of relaxation (reduced muscular tension
and cramps) Decreased risk of low back pain Reduced stress and tension Increased enjoyment Promotes self-discipline Unification of body, mind and spirit (e.g. Yoga) Improves ease and efficiency of movement Increased Range of Motion Improves skill in sport
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Reasons why stretching before exercise may not prevent injury
An increase in muscle compliance may cause tissues to rupture more easily.
Stretching before exercise will have no effect for activities where excessive muscle length is not an issue.
Stretching will not affect muscle compliance during eccentric activity, where most strains are believed to occur.
Stretching can produce damage at the cytoskeleton level.
Stretching appears to mask muscle pain in humans.
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Who should not Stretch? Everyone can learn to stretch Caution for people who have naturally
excessive ROM - should not stretch in extremes of ROM as joint stability should be maintained
Recent push to certify Yoga instructors locally, reduce incidence of injury to clients
Pregnancy - hormone Relaxin - softens ligaments and connective tissue especially in pelvis - excessive stretching can lead to hypermobility of low back
Table 54.2, 54.3 ACSM
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Flexibility Training Program Athletes should stretch following practice or as a
separate session (after sufficient warm up) Muscle is warm, collagen is elastic which allow greater
stretch May decrease muscle soreness
Training Program A planned, deliberate, and regular program of
exercises that can permanently and progressively increase the useable range of motion of a joint or set of joints over a period of time (Corbin and Noble, 1980).
Stretching recommended after sitting or standing for long periods - helps prevents discomfort (not enough to count as a training program)
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Duration and Frequency Variable opinions Duration
Beaulieu - 10-15 secs - progress to 45-60 secs over 4-5 weeks
Anderson - 10-30 sec easy; 10-30 sec developmental stretch
ACSM 10-30 seconds - but emphasize that connective tissue deformation and neuro-inhibitory effects require 30-90 seconds to effect tissue change and relaxation
Yoga - variable - 45-90 seconds Frequency
Beaulieu - 2-3 times / week Yoga - daily for 30-45 minutes - relaxation
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Controversy Optimum flexibility
sport specific? Types of stretching
Safety vs effectiveness Static vs dynamic stretching and
performance Dangerous stretches
Cautions in some guides, recommended in others?
Stretching during warm-up and cool-down Is it enough to effect changes in flexibility? Does it have an impact on injury or muscle
soreness?
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Ballistic Stretching(bouncing)
Advantages Development of
dynamic flexibility Effectiveness Team camaraderie Interest
Disadvantages Inadequate tissue
adaptation Soreness and injury Initiation of stretch reflex Inadequate neurological
adaptation Disadvantages outweigh
advantages
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Static Stretching Advantages Historical preference Effective and optimal Decrease possibility of
exceeding normal ROM
Less energy Less muscle soreness Recommended as
advantages outweigh disadvantages - especially for general population
Disadvantages Boring May overly dominate routine
due to time needed Allows body to cool during
warm up Principle of specificity -
effectiveness for improving dynamic flexibility?
Increase chance of injury by reducing amplitude of stretch reflex?
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Dynamic Stretching(mobility drills)
Advantages Focused on sport
specific movement Development of
dynamic flexibility Increases temperature Muscle is active Team camaraderie Interest Avoids bouncing and is
more controlled than ballistic stretching
Disadvantages Inadequate tissue
adaptation (ROM) Soreness after first sessions Inadequate neurological
adaptation advantages outweigh
disadvantages
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Dynamic Stretching(mobility drills)
Preferred method of stretching during warm up Actively moving joint through ROM required for sport Observe sport specific movement patterns, and select
exercises that mimic those patterns Build progressively through each exercise
Speed and ROM Perform under control
ROM often less than what could be achieved with ballistic type movements
Do not accelerate limb to end of ROM
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Dynamic Stretching
STRAIGHT-LEG MARCH
(for the hamstrings and gluteus muscles)
Kick one leg straight out in front of you, with your toes flexed toward the sky. Reach your opposite arm to the upturned toes. Drop the leg and repeat with the opposite limbs. Continue the sequence for at least six or seven repetitions.
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SCORPION
(for the lower back, hip flexors and gluteus muscles)
Lie on your stomach, with your arms outstretched and your feet flexed so that only your toes are touching the ground. Kick your right foot toward your left arm, then kick your leftfoot toward your right arm. Since this is an advanced exercise, begin slowly, and repeat up to 12 times.
Dynamic Stretching
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HANDWALKS
(for the shoulders, core muscles, and hamstrings)
Stand straight, with your legs together. Bend over until both hands are flat on the ground. “Walk” with your hands forward until your back is almost extended. Keeping your legs straight, inch your feet toward your hands, then walk your hands forward again. Repeat five or six times. G.R.
Dynamic Stretching
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Additional Classifications Passive stretching - partner or stretching machine
provides external force Active Stretching - person stretching provides force Proprioceptive Neuromuscular Facilitation
contract muscle prior to stretch- 6 sec contraction; 10-30 sec stretch (Contract - Relax) Autogenic inhibition Golgi tendon organ and muscle spindle relaxation
Some also coincide stretch with contraction of agonist (ms opposite one being stretched) (Contract - Relax (Agonist Contract)) Reciprocal inhibition
Increased range of motion over static stretching More motivation required - beneficial to have knowledgeable
partner More time Increase pain and soreness and injury?
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