A person attempting to catch her breath will often place the upper extremities in a closed chain position.Which principle of muscle action accounts for why this is effective?

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Quizplus · Accepted Answer

Reversal of muscle action occurs when the origin of the muscle moves towards the insertion instead of the typical insertion moving towards the origin. In the case of catching one's breath, placing the upper extremities in a closed chain position (e.g., hands on knees after running) stabilizes the arms and shoulders, allowing the muscles of the shoulder complex to stabilize the upper body. This stabilization allows the diaphragm and accessory muscles of respiration to work more efficiently in expanding the thoracic cavity and drawing air into the lungs, rather than being used to stabilize the upper body.

A Person Attempting to Catch Her Breath Will Often Place