What term describes a muscle that assists the prime mover during contraction?

The term that describes a muscle that assists the prime mover during contraction is 'synergist.' Synergist muscles support the primary muscle, or agonist, by helping with the movement or stabilizing the joint. For instance, when performing a bicep curl, the biceps brachii is the prime mover, while the brachialis and brachioradialis act as synergists, facilitating the elbow flexion alongside the biceps.

Understanding the role of synergists is crucial in exercise science as this knowledge helps in designing effective workouts and rehabilitation programs. Synergists can enhance the efficiency of movements and help prevent injuries by sharing the workload during exercise, ensuring the primary muscles are not overworked.

In contrast, antagonists oppose the action of the prime mover, which is essential for controlled movements and stability but do not assist in contraction. The agonist is synonymous with the prime mover itself. The term isometric refers to a type of muscle contraction where the length of the muscle does not change, which does not pertain to the question of assistance during contraction.