3. What is an opposing muscle and what does it do?

Opposing or antagonist muscles are the muscles that do the opposite of the muscle that is working. For example, when a person performs a bicep curl, the elbow flexes as the bicep shortens. The opposing muscle group in this case is the triceps, which lengthen or elongate in order to allow this movement at the elbow.

Opposing or antagonist muscles are the muscles that do the opposite of the muscle that is working. For example, when a person performs a bicep curl, the elbow flexes as the bicep shortens. The opposing muscle group in this case is the triceps, which lengthen or elongate in order to allow this movement at the elbow.