The term for the primary muscle responsible for a movement is?

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

Answer: (B)

The term for the primary muscle that drives a movement is the agonist. This muscle is the main force behind the action, contracting to produce the movement you’re performing. For example, in a bicep curl, the biceps brachii acts as the agonist by contracting to bend the elbow.

Other muscle roles help the movement work smoothly: the antagonist is the muscle that would oppose that action if it were contracting (like the triceps during a bicep curl), the synergists assist the agonist by guiding and supporting the motion, and stabilizers hold the surrounding joints steady so the movement can happen without unwanted wobble or collapse.

So, the primary mover— the one that creates the action—is the agonist.