These muscles (or their tendons) apart from the short head of the biceps femoris, are commonly known as the hamstrings. The depression at the back of the knee, or "kneepit" is the popliteal fossa, colloquially called the "ham". The tendons of the above muscles can be felt as prominent cords on both sides of the fossa—the biceps femoris tendon on the lateral side and the semimembranosus and semitendinosus tendons on the medial side. The hamstrings flex the knee, and aided by the gluteus maximus, they extend the hip during walking and running. The semitendinosus is named for its unusually long tendon. The semimembranosus is named for the flat shape of its superior attachment.