Which muscles act as agonists during a leg press at the knee joint?

The quadriceps muscles are the primary agonists during a leg press at the knee joint. This group consists of four muscles: the vastus lateralis, vastus medialis, vastus intermedius, and the rectus femoris. When performing a leg press, especially as the knee extends to push the platform away from the body, these muscles contract to facilitate extension at the knee joint.

The action of the quadriceps is critical because they primarily provide the force needed to lift the weight in the leg press. The vastus lateralis, medialis, and intermedius contribute to this extension, while the rectus femoris additionally assists due to its involvement in hip flexion, although its primary role is knee extension when the hip is flexed.

Other muscle groups, such as the hamstrings and gluteus maximus, while involved in lower body exercises, primarily function as antagonists during the leg press, as they help control the movement and stabilize the joint rather than executing the primary action of extension. Similarly, muscles like the adductors, hip flexors, calves, and tibialis anterior play supporting roles or are involved in different actions and do not act as the main movers during the leg press. Therefore,