Which muscle group opposes the actions of the biceps during elbow extension?

The triceps brachii is the muscle group that opposes the actions of the biceps during elbow extension. When the biceps brachii contracts, it functions primarily to flex the elbow and supinate the forearm. In contrast, the triceps brachii is responsible for extending the elbow. These two muscle groups work in opposition to maintain balance and control of arm movement.

During activities that involve elbow flexion, such as lifting or pulling, the biceps become the primary movers, while the triceps act as antagonists, relaxing to allow for the movement to occur. Conversely, when the elbow extends, the triceps contract to perform the extension while the biceps lengthen. This antagonistic relationship is crucial for coordinated movements and proper joint function.

The other muscle groups listed do not play a primary role in opposing the actions of the biceps during elbow extension. The pectoralis major primarily functions in shoulder flexion and adduction, the brachialis assists the biceps in flexing the elbow, and the latissimus dorsi is involved in shoulder movements rather than directly in elbow actions.