The action of muscles, is the name for the movement that results from contraction of the muscle. Typically, one end of a muscle doesn’t move; this end stays in place and is called the origin. The other end of the muscle moves and is called the insertion. Most muscles work together with a joint and the type of muscle action depends on the nature of the joint.
There are five common types of muscle action that happen as a result of muscle contraction: flexion, extension, rotation, abduction, and adduction. There are also special types of muscle action that occurs at certain types of joints. For example, the muscle movement that enables the thumb to touch the tips of the other fingers is called opposition.
