WHAT ARE THE HAMSTRINGS?
There’s a misconception that the hamstring is one large muscle running down the back of the thigh. The hamstrings are actually a group of three muscles: the semitendinosus, the semimembranosus and the biceps femoris.
The three muscles run from the bottom of the pelvis to the the knee joint, helping you bend your knees and extend the legs straight back. The hamstring tendons attach the muscles to bone.