What is the definition of a synergist muscle?

A synergist muscle is defined as a muscle that assists the prime mover in its action. This means that when a primary muscle, or prime mover, is responsible for initiating and carrying out a particular movement, the synergist muscles help facilitate that movement by providing additional force, stabilizing the joint, or preventing unwanted movement.

For example, during a bicep curl, the biceps brachii functions as the prime mover for elbow flexion, while muscles such as the brachialis act as synergists by supporting this action. The collaboration between these muscles allows for more efficient and controlled movement, making the action smoother and more effective.

This cooperation is essential for maintaining proper movement patterns and can help reduce the risk of injury during physical activities. Thus, the role of a synergist is crucial in ensuring that the prime mover can perform its function optimally.