What is the prime mover in a bent-over lateral raise exercise?

In a bent-over lateral raise exercise, the primary muscle responsible for the movement, known as the prime mover, is the posterior deltoids. This exercise involves raising the arms sideways while bent over, which primarily targets the muscles responsible for shoulder abduction and extension in the horizontal plane.

The posterior deltoids play a crucial role in this movement, as they are activated to lift the weights away from the body. Alongside the posterior deltoids, the exercise also engages other muscles such as the trapezius and rotator cuff muscles, but the posterior deltoids are the main focus of the movement.

In contrast, the biceps and anterior deltoids are not primary movers in this exercise. The biceps mainly function in elbow flexion, while the anterior deltoids are engaged in movements that involve shoulder flexion and lifting in front of the body, which is not the action occurring during a bent-over lateral raise. Thus, identifying the posterior deltoids as the prime mover aligns with the mechanics of this particular exercise.