I’ve heard my fair share of hamstring stories from athletes and people in general who believe they have “tight” hamstrings. In order to gain an appreciation and understanding of the muscle group let’s look at where these group of muscles attach.
There are 3 hamstring muscles: the semitendinosis, semimembranosis, and biceps femoris. The group of muscles attach to your pelvis (ischial tuberosity), run down the back of your leg and attach to your lower leg past the knee. More simply, the “semis” run down the medial aspect while the biceps femoris runs down the lateral portion (both attaching on the lower leg). Because the hamstrings have different attachment points on the lower leg, they serve multiple functions such as knee flexion and hip extension. Another vital but often overlooked function of the hamstrings is their stabilizing role on the pelvis. Since they attach on the ischial tuberosities, they try to prevent (stabilize) the pelvis from forwardly “tipping” (anterior pelvic tilt). When we see athletes coming in with forwardly tipped pelvis’ the one thing we want avoid is constant hamstring stretches. The picture below shows how the hamstring have lost their stabilizing function on the pelvis.
The hamstrings become lengthened as a result of pelvic position so while someone may “feel” tight in their hamstrings, they aren’t. What the hamstrings are doing is holding on for dear life to prevent the pelvis from tilting forward any more. Why would you stretch a muscle that is already in a lengthened position? It can be extremely frustrating to see people performing endless stretches or pushing through a hamstring stretch when it may be the last thing they need. In the next few days, I will go over strategies in which to improve the faulty pelvic position that we see with many of our athletes.