During elbow flexion, which muscle acts as the agonist?

During elbow flexion, which muscle acts as the agonist?

• A. Bicep
• B. Tricep
• C. Deltoid
• D. Latissimus dorsi

Answer: (A)

In elbow flexion, the agonist is the muscle that directly drives the elbow to bend. The biceps brachii is the primary elbow flexor; when it contracts, it pulls the forearm up toward the upper arm, reducing the elbow angle. The triceps brachii has the opposite action (it extends the elbow), so it acts as the antagonist during this movement. The deltoid and latissimus dorsi mainly affect the shoulder, not the elbow, so they don’t drive elbow flexion.

In elbow flexion, the agonist is the muscle that directly drives the elbow to bend. The biceps brachii is the primary elbow flexor; when it contracts, it pulls the forearm up toward the upper arm, reducing the elbow angle. The triceps brachii has the opposite action (it extends the elbow), so it acts as the antagonist during this movement. The deltoid and latissimus dorsi mainly affect the shoulder, not the elbow, so they don’t drive elbow flexion.