Embody Change Structural Integration

 

Newsletter - June 2009

Freedom for the hamstrings

Who do you know that seems to have especially tight hamstrings? I find that tall guys with flexible backs and teen boys who have just been through a growth spurt often have the tightest hamstrings, and it seems these people characteristically feel little reward or productive result from trying to stretch them. My father, my uncle, and my father-in-law all experience tightness through the back of the thighs, and so do many of the young men I know who are about to step out into the world on their own. So in honor of Father’s Day and all the June graduations, I’d like to share with you my favorite remedy for tight hamstrings, the “bent-knee hamstring stretch.”


Of course, it’s not just the tall guys who can benefit from this particular stretch. Many runners, bikers, or people who spend lots of time in chairs also feel chronically restricted through the hamstrings. I personally feel the most benefit from this stretch after a long day of airline travel or several days in a row of sitting at the computer, or right after a long run.


If you are in a hurry to explore the bent-knee hamstring stretch, scan to the end of the article and read the section “How to Find a Productive Stretch.” For those of you with a bit more time, let me start by explaining hamstring anatomy from a Structural Integrator’s perspective.


Anatomy of the thigh

We can think of the thigh as divided into three main muscle compartments: quadriceps group in the front, adductor group at the inner thigh, hamstring group in the back. You can compare these compartments, and the individual muscles within the compartments, to sections of an orange. Each of these muscles is wrapped in connective tissue called fascia (FAH-shuh). [Fascia actually wraps around and supports all of our organs, bones, nerves, and blood vessels; it weaves through muscles and is the primary substance forming tendons and ligaments. Fascia is the fabric of the body that holds our parts in relationship to one another.]


The fascia wrapping around one muscle (equivalent to the membrane around an orange section) lies against the fascia wrapping around an adjacent muscle, forming a double layer. There should be some gliding movement allowed between these layers, but if they are closely adhered, the muscles will have a hard time moving independently. In the posterior thigh, fascial adhesion between the hamstrings and the underlying adductor magnus, will limit the extent to which they can lengthen separately from one another. Because fascia wraps around and supports the nerves and blood vessels that run between muscle compartments, there is extra intermuscular fascia associated with branches of the sciatic nerve running between the hamstrings and adductor magnus, and this is where we find another important factor contributing to persistently tight hamstrings!


Tethered and trapped nerves

When adjacent muscles are glued too tightly together, the nerves that run between them are tethered so snugly within the intermuscular layers of fascia that movement or stretching can then put sheer stress upon the nerves. A slight amount of sheer stress, caused by neighboring muscles pulling in different directions, might help release accumulated fascial tethering, but lots of sheer stress can trigger neurons to fire. Stressed motor neurons can cause muscle fibers to contract, increasing the tone of the muscle, shortening it, and making it harder for the person stretching to find a release. Additionally, stressed sensory nerves may elicit pain. Pain and unresponsiveness to stretch are clues that it is time to modify the stretch, so that it more effectively targets the area where the muscle layers are glued together.


How layers of fascia in the thigh become glued together

Every night new hydrogen bonds develop between collagen fibers in the fascial layers, and over time these bonds accumulate. Stretching and exercise tend to break the hydrogen bonds gluing together adjacent layers. So, moving every day helps the layers retain enough freedom to glide against one another. However repetitive activity that moves in only a few limited directions (e.g. biking and running, which require minimal lateral movement) won’t release these hydrogen bonds as effectively. If adjacent muscles, such as the hamstrings and adductor magnus, always contract and lengthen in unison, there is minimal tug or shear stress on the intermuscular fascial layers, and in time, they become more and more glued together. Inactivity and compression (e.g. sitting in hard or confining chairs) further contributes to the glueyness between these fascial layers.


In the back of the thigh, the hamstrings and adductor magnus can do similar work—both cross the hip joint, and therefore they are both involved in hip extension and can act to stabilize the pelvis from behind. However, the hamstrings cross the knee joint, so they are shortened by bending the knee and lengthened by straightening the knee, while the adductor magnus is not lengthened or shortened by knee movement. The problem with “tight hamstrings” is not so much the length of the hamstrings, but the relationship between the hamstrings and the adductor magnus. A straight-knee stretch may not change the relationship between the layers, whereas a bent-knee stretch can begin to free the hamstrings from the underlying adductor magnus, thus reducing sheer stress on many local branches of the sciatic nerve, which allows both muscles to gradually release. Read on, and then try out the following stretch to understand how it works.


Bent-knee hamstring stretch

First select a chair or the arm of a sofa, something you can put your foot on while you stand on the other leg. (You might want to position yourself near a wall, so that you can put your hand on something for support and balance.) Make sure that you start with a big bend in the knee of the leg that is propped up. Bend it at ninety degrees to start and fold forward so that your belly and chest rest on your thigh. Bend your knee even more, if your belly is not touching yet. Now, KEEPING that relationship between belly and thigh, and resting your body against your thigh, flex your ankle upward (move toes toward your knee), and slowly slide your sitting bone backward. This will BEGIN to have a straightening effect on your knee.


Stop moving and hold your position as soon as you feel a stretch in the middle of your posterior thigh. If you are tight in the hamstrings, your knee should still be quite bent, and yet, you will feel a significant stretch or a pull in the muscles. This is where you want to be. In this sequence, you are first lengthening adductor magnus; then you are starting to lengthen the hamstrings. In doing so, you are asking the hamstrings to glide past the adductor magnus, which begins to differentiate the two layers of muscle and free those branches of the sciatic nerve. Linger here for a few full breaths, then try shifting your hips toward your other leg, and feel how the stretch changes. Experimentally shift your hips the opposite direction, then find the angle at which you feel the strongest stretch. Hang out there for a couple more full breaths, then slowly return to standing on both legs.


You can go into a regular forward bend now, hanging down to test the sensation in the back of your legs. Likely, you will feel less pull in the leg that just did the bent-knee stretch. If both legs still feel similarly tight, check your hands visually to see how far each one hangs toward the floor. This should tell you that the side you just stretched has lengthened a bit. Now try the same sequence on the other leg.


Whether you are a tall guy or not, I hope that this stretch offers you a new way to get at your tight legs. As the layers in the back of your thighs release and stretching actually becomes more productive and pleasurable, it is possible to find significant hamstring relief and freedom. Many back injuries, pulled calf muscles, and even foot problems can be helped (or prevented) through release of tightly adhered fascial layers in the posterior thigh. So if you find this approach feels satisfying to you, I hope you will teach it to your dad, your son, or one of your friends who seems to have chronically tight hamstrings. Good luck, and remember to stretch regularly!



© Kirstin Schumaker 2009