NETA Personal Trainer Practice Exam 2026 - Free Personal Trainer Practice Questions and Study Guide

Muscle fibers that play a supportive role in facilitating movement, rather than being the primary movers, are known as synergists. These muscles assist the primary muscles, or agonists, during a given movement, ensuring optimal functioning and stability. For instance, when performing a bicep curl, the biceps brachii acts as the primary mover, while other muscles, like the brachialis and brachioradialis, assist in the action.

The role of synergists is crucial in ensuring that movements are smooth and efficient, preventing strain or injury that can occur when the primary movers are left to perform alone. Their contributions help maintain balance and proper joint mechanics throughout a movement.

In contrast, agonists are the main muscles responsible for the movement, antagonists work in opposition to the agonists to control and stabilize movement, and flexors refer specifically to muscles that decrease the angle between two body parts—showing the importance of the specific roles that different muscle fibers play in overall movement.