physiological basis of flexilibility

PHYSIOLOGICAL BASIS OF PHYSIOLOGICAL BASIS OF FLEXILIBILITYFLEXILIBILITY

Please refer to CHAPTER 20 of Plowman (2011): Neuromuscular Aspects of Movementpp. 583-612

FLEXIBILITYFLEXIBILITYAbility of a joint or a series of joints

to move smoothly & easily through a FULL RANGE OF MOTION.

DYNAMIC FLEXIBILITY- degree to which a joint can be moved by a muscle contraction ACTIVE RANGE OF MOTION)

STATIC FLEXIBILITY- degree to which a joint may be PASSIVELY moved to the end points in the range of motion

FACTORS AFFECTING FACTORS AFFECTING FLEXIBILITYFLEXIBILITYBony structuresExcessive fatSkin (scarring- tissues become

inelastic)Muscle & tendonsConnective tissue- ligamentsNeural tissue tightnesshypermobilityu

MEASURING FLEXIBILITYMEASURING FLEXIBILITY

In the LABORATORYMeasured through angular displacement

(in degrees)GONIOMETERFLEXOMETER

In the FIELDMeasurement of linear distances

between segments or from an external objectsE.g. Sit-and-reach

GONIOMETER FLEXOMETER

STUDIES AND STUDIES AND COMMON BELIEFS ON COMMON BELIEFS ON FLEXIBILITYFLEXIBILITY

FEMALES AS THE MORE FEMALES AS THE MORE FLEXIBLE SPECIESFLEXIBLE SPECIES

NO consistent data on INFLUENCE OF SEX on flexibility◦Women are ONLY more flexible than

men when HIP FLEXIBILITY is measured

◦Studies show that there is no generalized pattern of flexibility superiority of females over males.

READ MORE IN Plowman (2011) page 599- 600

AGE & FLEXIBILITTYAGE & FLEXIBILITTYBetween 10-15 years oldLumbar flexibility- decreasesLateral flexion- increases

Hip flexibility-increases steadily for women from 10-18 y.o-decreases 5-13 y.o., increase

Studies equivocal: some show a decline, some show no difference

FLEXIBILITY EITHER DECLINES OR STAYS THE SAME THROUGH THE ADULT YEARS, DEPENDING ON THE INDIVIDUAL’S LEVEL OF ACTIVITY

STRETCHING TECHNIQUESSTRETCHING TECHNIQUES

1. BALLISTIC2. DYNAMIC3. STATIC4. PROPRIOCEPTIVE

NEUROMUSCULAR FACILITATION

READ MORE IN Plowman (2011) page 601-603

BALLISTIC◦Involves bouncing movements◦Repetitive contractions of Agonist lead to

quick stretches of the Antagonist muscle◦Effective in improving ROM◦If force from jerks & pulls exceeds tissue

extensibility-muscle injury

DYNAMIC◦Consists of controlled stretches w/c are

recommended prior to beginning an acivity◦Focuses on functional movements

STATIC◦Passive stretching of an antagonist muscle

by placing it in a maximal stretch and holding it

15- 30 seconds, 3-4 repetitions per joint

PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION(PNF)◦A technique that combines alternating

contractions & stretches◦Consists of 10 seconds active push

phases + 10 seconds passive relaxation phase

slow-reversal-hold relax Contract-relax Hold-relax

NEUROPHYSIOLOGICAL NEUROPHYSIOLOGICAL BASIS OF STRETCHINGBASIS OF STRETCHING

The Reflex ArcThe Reflex Arc

Reflex – rapid, predictable, and involuntary responses to stimuli

Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector

Simple Reflex ArcSimple Reflex Arc

Types of Reflexes and RegulationTypes of Reflexes and Regulation

Autonomic reflexes

Smooth muscle regulation

Heart and blood pressure regulation

Regulation of glands

Digestive system regulation

Somatic reflexes

Activation of skeletal muscles

MYOTATIC (STRETCH) MYOTATIC (STRETCH) REFLEXREFLEXOccurs in response to a sudden

change in LENGTHWhen a muscle is quickly

stretched, MUSCLE SPINDLE fibers (mechanoreceptors) are activated causing s REFLEX CONTRACTION

Muscle spindlesMuscle spindles

INVERSE MYOTATIC INVERSE MYOTATIC REFLEXREFLEXContraction of a skeletal muscle

or stretching increases TENSION and stimulates the GOLGI TENDON ORGANS (GTO)

Results in a REFLEX RELAXATIONServes as protective function

against tension that might cause muscle & tendons to be torn

Golgi Tendon Organs Golgi Tendon Organs (GTO)(GTO)

slow stretches exceeding six (6) seconds causes REFLEX RELAXATION, allowing muscle to stretch through relaxation to exceeding extensibility limit

REFLEX INHIBITION- reflex relaxation of the antagonist muscle in response to contraction of the agonist◦(e.g.contraction of quadriceps

muscle relaxes the hamstrings muscle group)

PHYSIOLOGICAL RESPONSES PHYSIOLOGICAL RESPONSES TO STRETCHINGTO STRETCHINGDelayed Onset Muscle Soreness

◦No definite studies pointing to a decreases in DOMS with stretching

Range of Motion◦15-30 seconds of stretching more

effective ◦No additional benefit beyond 30sec.

Stretch◦Increased ROM from acute bout of

stretching lasts for 60-120 minutes

Injury Prevention◦Stretching before exercise DOES NOT

necessarily prevent Injury from occurring.◦ Individuals with Poor flexibility for the

performance of a task , however, puts them at greater risk for injury

Performance◦Belief that stretching can enhance

performance NOT SUPPORTED BY LITERATURE.

◦Some studies show decrease in muscle strength after pre-activity stretching

◦Pre-stretching may NEGATIVELY AFFECT jumping.