Question

Explain why maximal wrist extension is not passive insufficiency of the muscles generating grip force. Since this is not an example of passive insufficiency, explain why maximal wrist extension is generally not the ideal wrist position for generating maximum grip force.

Answer 1

The passive insufficiency is the inability of the muscle that are aided with multiple joints to extend completely to a degree that allows full motion of the joints allows simultaneous crossing of the joints. In such cases, the muscle fails to extend far and long enough. This happens as there are multiple joints which are not able to undergo a full stretch. The maximal wrist extension is not passive insufficiency because in this case the muscle or the wrist can be extended completely and hence is able to generate grip force. The human hand is able to generate grip force when the wrist is maximum extended because of active insufficiency where placing the muscle in a shortened position tends to reduces the total ability of the generated force. The muscle is not able to shorten enough and gives a cramping sensation.

The maximal wrist extension is not ideal for wrist position for generating maximum grip force because the muscles are not able to completely extend and hence it undergoes pain and cramping. In this the wrist is not longer able to apply effective due to bending insufficiency and muscle shortens its length.