twitch

A twitch is a brief, spasmodic contraction of muscle fibers, or a slight jerk of a body part. Skeletal muscles can undergo a rapid, intense contraction in response to a single electrical shock, known as a twitch. This mechanical response involves an increase in tension that lasts for about 200 milliseconds before decreasing. The maximum tension developed during a tetanus, a sustained contraction, is typically greater than that of a single twitch because the contractile elements have more time to stretch the muscle's elastic components. Fasciculation, the twitching of muscle fibers controlled by a single motor nerve cell, can occur in healthy individuals but may indicate disease of motor nerve cells.123