Which muscle is NOT part of the hamstring group?

The rectus femoris is not part of the hamstring group; it is one of the quadriceps muscles located at the front of the thigh. The hamstring group is comprised of three primary muscles: the semimembranosus, biceps femoris, and semitendinosus, which are located at the back of the thigh. These muscles play a crucial role in knee flexion and hip extension. In contrast, the rectus femoris primarily functions to extend the knee and assist in hip flexion, making it anatomically and functionally distinct from the hamstring muscles. Understanding muscle groups and their functions is essential for tasks such as assessing injuries, creating rehabilitation plans, and fitting orthotic devices.