When performing a bicep curl, what type of movement occurs at the elbow joint?

During a bicep curl, the primary movement that occurs at the elbow joint is flexion. This action involves decreasing the angle between the forearm and the upper arm as the arm curls up toward the shoulder. The biceps brachii muscle, located at the front of the upper arm, contracts to pull the forearm upward, thereby facilitating this flexion movement.

Understanding why flexion specifically occurs is essential in various fitness contexts, such as ensuring proper form during exercises and targeting muscle groups effectively. This type of movement is characterized by the muscle shortening (in this case, the biceps), leading to this specific reduction in joint angle, which is key in many arm movements and strength training exercises.