What muscle is the prime mover in a squat?

In a squat, the quadriceps are the primary movers, making them crucial for the action of extending the knees. This muscle group, located at the front of the thigh, is activated during the lowering phase of the squat as well as when pushing back up to the standing position. The quadriceps work to straighten the knee joint after descending into the squat position, effectively enabling the upward movement that completes the exercise.

While other muscle groups like the hamstrings, abductors, and adductors play supportive roles in stability and balance during the squat, none provide the primary force required for knee extension in the same way the quadriceps do. The hamstrings, located at the back of the thigh, assist in bending the knee and stabilizing the movement, but they do not serve as the main movers. The abductors and adductors help stabilize the hips, which is important for overall form, but again, none serve the primary action of extending the knee during a squat. Thus, the quadriceps’ role as the main muscle engaged in the biomechanical action of a squat is why this choice is the correct one.