When a muscle fiber is subjected to a stimulus it contracts completely is called?

When a muscle fiber is subjected to a stimulus and contracts completely, this phenomenon is known as the "all-or-nothing response." In this response, if the stimulus reaches a certain threshold, the muscle fiber will contract fully; if it does not reach this threshold, there will be no contraction. This principle applies to individual muscle fibers, while whole muscles can exhibit varying degrees of contraction based on the number of fibers activated.