Transcript Flexibility (Testing and Training) 1

Flexibility
(Testing and Training)
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Outline
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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;
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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
NSCA - Essentials of Strength Training and Conditioning 2008
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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 Curve
Text 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 relaxant - 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 45 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
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
NSCA - Essentials of Strength Training and Conditioning 2008
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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
NSCA - Essentials of Strength Training and Conditioning 2008
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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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Dynamic Stretching
 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.
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Dynamic Stretching
 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.
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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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NSCA - Essentials of Strength Training and Conditioning 2008
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