What is the name of the muscle that assists with a movement but is not the primary mover?

The term that describes a muscle that assists with a movement but is not the primary mover is known as a synergist. Synergist muscles work in conjunction with the agonist (the primary mover) to enhance and stabilize the movement. For instance, during a bicep curl, the biceps brachii is the primary mover, while the brachialis and brachioradialis act as synergists to assist in this action, providing support and improving efficiency.

Understanding the role of a synergist is essential for designing effective training programs because recognizing the involvement of these supporting muscles can help in injury prevention and ensure balanced development across muscle groups. This knowledge assists trainers in creating workouts that not only target primary muscles but also engage synergistic muscles, thereby optimizing performance and reducing the risk of overuse injuries.