Reciprocal Inhibition: A Case Study

These provide proprioceptive information on movement as the skin is stretched at various points along the ROM (Gregg 1994 p15 ass)

For example, if the knee is fully extended, the skin behind the knee becomes taut, signaling knee extension.

Thermoreceptors and pain receptors are other receptors in the skin. These receptors generate signals that stimuli the motor responses of the flexor reflex and crossed extensor reflex (withdrawel reflexed). They create a reflexive motor reaction to remove a body part from a dangerous stimulus. Eg. stepping on a nail; the hip and knee involved side flex while the contralateral extensors activate to support the limb.

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• What levels can the signal be interpretted at?

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Reciprocal Inhibition •

Control

There are very fast, involuntary and unconscious reflexes controlled by the spinal level, that are influenced directly by afferent information from joint receptors. These reflexes are coordinatinated between agonist and antagogonist muscles (p17). Sherrington(1906) identified the coordination as the law of reciprocal inhibition: When an agonist contracts, its antagonist automatically

Synergists may include secoundary movers, stabliziers, or neutralizers. For example, during shoulder rotation, the rotator cuff is active. However, the rhomboids, serratus anterior, and trapezius must work as stabilizers of the scapula to ensure a stable orgin for the rotator cuff. Therefore, pseudoweakness of the rotator cuff may be caused by poor stabilization of the scapula; if the scapula is stabilized manually, the patient demonstrates normal strength of the rotator cuff.

(p30 chain reactions)

• What does Synergistic Dominance mean?

• Give an example

Since all muscles are assisted by synergistic muscles, if the main agonist is not firing correctly, the synergistic muscle will activate. This is referred to as synergistic dominance. In this case, due to a decreased neural drive to the gluteus maximus, the hamstrings act as the synergist and take over the role of the gluteus maximus.

Although the hamstring functions as a good synergist to the gluteus maximus, it is not designed to be the sole hip extensor. Synergistic dominance by the hamstrings can lead to premature fatigue, overuse and overactivation of the hamstring muscles. This could put the client at risk of hamstring strains, hamstring cramps and SI joint pain.

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