FLEXIBILITY

What is Joint Flexibility?A description of the relative ROM allowed at a joint in different directions

ROM: the angle through which a joint moves from anatomical position to the extreme limit of segment motion in a particular direction.

Joint Flexibility Range of motion is measured directionally from anatomical position (zero).

Static FlexibilityAn indicator of the relative tightness or laxity of a joint.

• the ROM present when a body segment is passively moved (by an exercise partner or clinician)

Dynamic FlexibilityROM achieved by virtue of muscle contraction

Factors That Influence Joint FlexibilityShape and Tightness

Shape of Joint ComponentsThe articulating bone surface, muscle tissue or fat terminate movement at extreme ROM.

Tightness of Muscle & CollagenStretching increases extensibility of both tissues. Lack of stretching significantly diminishes extensibility over time.

*Increased temperature increases flexibility of collagen.

NEUROMUSCULAR RESPONSE & JOINT FLEXIBILITY

Golgi Tendon Organs (GTO) Sensory receptors that influence extensibility Located in the muscle-tendon junction and in

the tendons at both ends of muscles Stimulated by tension produced by muscle

contraction or passive muscle stretch Inhibits tension in agonist muscle (promote

relaxation) & initiate tension development in antagonists

Muscle Spindles Sensory receptors that respond to:

amount of muscle (static response) rate of muscle lengthening (dynamic response)

Muscle spindles will: provoke reflex contraction in stretched muscle inhibit tension in antagonists..

Comparison of: GTO Muscle Spindle

Location

Within tendons near the muscle-tendon junction in series with muscle

fibers

Interspersed among muscle fibers in

parallel with the fibers

StimulusIncrease in muscle

tensionIncrease in muscle

length

Response

Inhibit tension development in

stretched muscle

Initiate tension development in

antagonist muscle

Initiate rapid contraction of

stretched muscle

Inhibit tension development in

antagonist muscles

Overall Effect Promote stretch in muscle being stretched

Inhibit stretch in muscle being

stretched

GTO PROMOTES RELAXATION

MUSCLE SPINDLES INHIBIT STRETCH

Therefore, maximizing GTO &

minimizing the muscle spindle increases joint flexibility.

Techniques for increasing Joint FlexibilityActive & Passive StretchingBallistic & Static StretchingPNF

Active StretchingProduced by contraction of the antagonist muscles

Ex. Quadriceps contract so that hamstrings are stretched

Advantage: exercises muscle group used to develop force

Passive StretchingProduced by a force other than tension in the antagonist muscles

Ex. Gravitational force, force applied by another body segment or by another person.

Advantage: movement can be carried out father beyond the ROM

Static StretchingMaintaining a slow, controlled, sustained stretch over time.

usually 20-30 seconds

Advantage: does not activate muscle spindle response that inhibits stretching

Ballistic StretchingSeries of quick, bouncing-type stretches.

The potential for injuries is heightened due to activation of muscle spindle which inhibits stretching

Proprioceptive Neuromuscular Facilitationa group of stretching procedures involving alternating contraction and relaxation of the muscles being stretched