ACTION: extends the hip, flexes the knee
REFERRAL: posterior knee and hip

COMMENTS: These three muscles, the semimembranosus, the semitendinosus and the biceps femoris, all connect to the hip at the ischial tuberosity. When they contract with the gluteus maximus, they extend the hip . A common site of injury is the attachments to the ischial tuberosity, and this is called a hamstring tendon strain.
When these muscle contract, they cause a posterior rotation of the pelvis. In this case the rectus abdominis will also be tight, and these two muscle groups should be released together.