Which muscle type describes muscles that assist prime movers during movements?

• A. Agonist
• B. Antagonist
• C. Synergist
• D. Stabilizer

Answer: (C)

When a movement happens, the main muscle driving the action is supported by helper muscles that ensure the movement is smooth and efficient. Those helper muscles are synergists. They assist the prime mover by adding extra force, guiding the motion to occur in the correct path, and helping stabilize the joint so unwanted movement is minimized.

For example, in elbow flexion, the biceps brachii is the primary mover, while the brachialis and brachioradialis often act as synergists, sharing the workload and helping the elbow bend more effectively. Stabilizers or fixators may hold the joint steady to allow the prime mover to work, and antagonists oppose the movement to help control it.

So muscles that assist prime movers during movements are synergists.