When a muscle assists another muscle, what is it acting as?

When a muscle assists another muscle during a movement, it is acting as a synergist. Synergist muscles support the action of the prime mover (or agonist) by helping to produce the desired motion and stabilize the joint around which the movement occurs. This assistance is crucial as it improves the efficiency and smoothness of the movement, allowing for better control and coordination.

Understanding the role of synergists is important, especially in exercise programming and technique, as these muscles help prevent injury by providing stability and support during dynamic movements.