ACSM Personal Trainer Certification Practice Exam 2026 – All-in-One Study Resource to Achieve Certification Success!

The muscle primarily responsible for elbow flexion during exercise is the biceps brachii. This muscle plays a crucial role in lifting and pulling movements, as it contract to bend the elbow, bringing the forearm closer to the upper arm. The biceps also assist in supination of the forearm, which means turning the palm upwards. Its anatomical position and functional capabilities make it the key muscle activated during tasks requiring elbow flexion, such as bicep curls or pull-ups.

In contrast, the triceps are located on the posterior aspect of the arm and are responsible for elbow extension, which means they perform the opposite function to elbow flexion. Deltoids are primary muscles involved in shoulder movements and do not directly contribute to elbow flexion, while quadriceps are located in the front of the thigh and primarily facilitate knee extension. Therefore, the biceps is the correct and primary muscle activated during elbow flexion exercises.