Therapeutic Exercise

Question 1

Two types of PNF stretches

Answer 1

CR (contract relax): The contraction of the target muscle

CRAC (contract relax antagonist contract): the contraction of the opposing muscle

Question 2

What are the 4 theory names for PNF stretching?

Answer 2

1) reciprocal inhibition
2) autogenic inhibition
3) stress relax
4) gate control

Question 3

What does the reciprocal inhibition theory describe?

Answer 3

The a1 afferent nerves from the OM enters the spinal cord and from there excitatory neurons activate inhibitory interneurons to the TM to initiate relaxation of the TM muscle. Therefore with increased relaxation there in increased ROM of the stretch with increased elongation of the muscle fibers

Question 4

What does the autogenic inhibition theory describe?

Answer 4

contraction of the TM stimulates the a1 afferent nerve fibers from the GTO and is sent to the spinal cord. In the spinal cord, the stimulus activates 1b inhibitory neurons and thus inhibit motor neurons of the TM. The relaxation of the target muscles result in a increase in elongation and increased ROM of the stretch

Question 5

What does the stress relax theory describe?

Answer 5

Occurs when MTU under constant stress
Viscoelastic properties mean that if the force is placed low and slow the MTU will gradually elongate (“creep”) = increased ROM

Question 6

What does the gate control theory describe?

Answer 6

Pressure signals travel in large myelinated afferent nerve fibres whereas pain receptors travel slower in unmyelinated or small myelinated afferent nerve fibres
Pressure signal make it to CNS before pain
Inhibition of pain signals in dorsal horn when patient is being stretched and contracts the elongated muscle due to pressure signals being highly activated
Any pain sensation is inhibited = able to tolerate an increased stretch

Question 7

What are the theories behind static stretching?

Answer 7

1) myogenesis
2) neuromuscular relaxation
3) viscoelastic changes
4) change in sensory perception

Question 8

Theories on muscle strengthening (skeletal adaptions)

Answer 8

increase of protein synthesis. Increase actin and mysosin filament.
muscle fiber type conversion (type IIb to type IIa)
fiber type selection for the appropriate activity

Question 9

Theories on muscle strengthening (neural adaptions)

Answer 9

increase MU recruitment
increase MU at one time (aka synchronization)
increase CNS involvement to the area
decrease in proprioception response to allow for less inhibition