CH. 13: Warm-Up and Stretching

stretch reflex

-during a rapid stretching movement, a sensory neuron from the muscle spindle innervates a motor neuron in the spine-the motor neuron then causes a muscle action of the previously stretched extrafusal muscle fibers

hinge joint

-ex. knee -movement primarily in sagittal plane -half the ROM of ball and socket joint

ball and socket joint

-ex. shoulder, hip -moves in all anatomical planes and have the greatest ROM of all joints

fibrosis

-fibrous connective tissue replaces degenerating muscle fibers -due to inactivity -common in older population

dynamic stretch

-functionally based stretching exercise that uses sports-specific movement to prepare the body for activity -aka mobility drills -places an emphasis on the movement requirements of the sport or activity rather than on individual muscles -ex. walking knee lift

hold-relax with agonist contraction

-identical to hold-relax in the first two phases -during the third phase, a concentric action of the agonist is used in addition to the passive stretch to add the stretch force -the final stretch should be of greater magnitude due to reciprocal inhibition

stretching recommendations

-15-30 sec to the point of discomfort -following practice and competition -for additional flexibility, perform a separate session

static flexibility

-ROM possible about a joint and its surrounding muscles during a passive movement -requires no voluntary muscular activity -gravity, a partner, or a machine provides the force

agonist contraction

-a concentric muscle action of the agonist -used during a passive stretch of the antagonist to achieve reciprocal inhibition

flexibility

-a measure of ROM -has static and dynamic components

Golgi tendon organs

-a mechanoreceptor located near the musculotendinous junction -sensitive to increases in muscular tension -when stimulated, the GTO causes a muscle to reflexively relax

general warm-up period

-aim is increase HR, blood flow, deep muscle temp., respiration rate, and perspiration and to decrease viscosity of joint fluids -5-10 min of slow activity (ex. jogging, skipping, dribbling)

ellipsoidal joint

-an oval-shaped condyle that fits into an elliptical cavity -ex. wrist -allowing movements in sagittal and frontal planes

dynamic flexibility

-available ROM during active movements and therefore requires voluntary muscular contractions -dynamic ROM> static ROM

contract-relax technique

-begins with a passive prestretch held to the point of discomfort for 10 seconds -the athlete moves through ROM against resistance with concentric muscle contraction -the final stretch should be of greater magnitude due to autogenic inhibition

hold-relax technique

-begins with a passive prestretch that is held at the point of mild discomfort for 10 seconds -partner provides force, while athlete resists movement for 6 seconds -athlete relaxes and a passive stretch is performed for 30 seconds -the final stretch should be of greater magnitude due to autogenic inhibition

specific warm-up period

-incorporates movements similar to the movements of the athlete's sport -8-12 min of dynamic stretching focusing on movements that work through the ROM required for the sport (ex. walking knee lifts) followed by sports specific movements of increasing intensity (sprint drills, bounding, jumping)

Warm-up

-increases muscle temperature, core temperature, and blood flow and also disrupt transient connective tissue bonds -Effects: faster muscle contraction and relaxation of both agonist and antagonist muscles, improvements in rate of force development and reaction time, improvements in muscle strength and power, lowered viscous resistance in muscles, improved oxygen delivery due to the Bohr effect, whereby higher temperatures facilitate oxygen release from hemoglobin and myoglobin, increased blood flow to active muscles, and enhanced metabolic reactions

ballistic stretch

-involves active muscular effort and uses a bouncing-type movement in which the end position is not held -ex. ballistic toe touch

muscle spindles

-located within intrafusal muscles fibers that run parallel to extrafusal muscle fibers -monitor changes in length

reciprocal inhibition

-relaxation that occurs in the muscle opposing the muscle experiencing the increased tension -accomplished when one simultaneously contracts the muscle that is being passively stretched -the tension in the contracting muscle stimulates the GTO and causes a simultaneous reflexive relaxation of the stretched muscle

autogenic inhibition

-relaxation that occurs in the same muscle that is experiencing increased tension -accomplished via active muscle contraction immediately before a passive stretch

proprioceptive neuromuscular facilitation (PNF) stretching

-requires partner and some expertise -both isometric and concentric muscle actions of the antagonist (the muscle being stretched) are used before a passive stretch of the antagonist to achieve autogenic inhibition -isometric action=hold -concentric action=contract -3 types: hold-relax, contract-relax, hold-relax with agonist contraction

static stretch

-slow and constant -end position held for 30 sec -includes the relaxation and concurrent elongation of of the stretched muscle -ex. toe touch

elasticity

-the ability to return to original resting length after a passive stretch

ROM

-the degree of movement that occurs at a joint -determined by connective tissue structure, activity level, age, and sex

plasticity

-the tendency to assume a new and greater length after a passive stretch

After performing the "hold-relax with agonist contraction" PNF stretch for the hamstrings, which of the following explains the resulting increase in flexibility? I. autogenic inhibition II. stretch inhibition III. reciprocal inhibition IV. crossed-extensor inhibition a. I and III only b. II and IV only c. I, II, and III only d. II, III, and IV only

a. I and III only

Dynamic stretching is the MOST similar to which of the following? a. specific warm-up b. general warm-up c. low-intensity stretch d. static stretch

a. specific warm-up

Stimulation of muscle spindles induces a a. relaxation of GTOs. b. relaxation of the stretched muscle. c. contraction of the stretched muscle. d. contraction of the reciprocal muscle.

c. contraction of the stretched muscle.

Which of the following stretching techniques decreases muscle spindle stimulation? a. dynamic b. ballistic c. static d. passive

c. static

When stimulated during PNF stretching, Golgi tendon organs allow the relaxation of the a. stretched muscle by contracting the reciprocal muscle. b. reciprocal muscle by contracting the stretched muscle. c. reciprocal muscle by its own contraction. d. stretched muscle by its own contraction.

d. stretched muscle by its own contraction.