The primary mover during a movement is referred to as what?

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

Answer: (A)

The muscle that provides the main force to produce a movement is called the agonist. This muscle acts as the primary mover, generating the major portion of the action. Other muscles play supporting roles: the antagonist opposes the movement to provide control and balance; stabilizers hold a joint steady so the movement can occur smoothly; and synergists assist the agonist by adding extra force or guiding the motion for efficiency. For example, in bending the elbow, the biceps brachii is the agonist, driving the flexion; the triceps brachii acts as the antagonist to oppose that movement; stabilizers around the shoulder help maintain position, and synergists like the brachialis assist the elbow flexion. So the primary mover during a movement is referred to as the agonist.