What Is A Hamstring?

(Originally posted on bcotoronto.com on Mar 27th, 2013)

Concluding the theme of March: Anatomy and Ergonomics, we will be discussing Hamstrings and their important role in the body. The hamstrings are a group of large muscles that run down the back of the leg from the bottom of the pelvis to the knee. They are the primary knee flexors and help our gluteus muscles with hip extension. The Hamstrings include the Biceps Femoris, Semimembranosus, and Semitendonosus.

Biceps FemorisSemitendinosusSemimembranosus

So why are they so important? Well, as I said before they are the primary movers in knee flexion which is an incredibly important movement. Just try walking or jumping without bending your knees. Even sitting for that matter would be difficult. Needless to say we use our Hamstrings every single day to move around so any injury to these muscles will significantly impact our activities during the day.

Hamstring strains are very common among athletes but also among the general population through slipping on ice or missing the curb of the sidewalk. Improper stretching or not stretching at all before exercising is also an extremely common way to injure your hamstrings. So we need to ask, why is this muscle group so easily strained? It is because the Hamstrings are chronically tight and short in the average population.

When a muscle is tight it does not have the ability to react properly and smoothly to changes that are force upon it. With respect to a slow, gradual change this is not a problem but fast changes, like missing a step or running without a warm-up, can strain the muscle. Muscles can be tight for two main reasons; overuse (as with Tennis Elbow or rotator cuff injuries) and postural pressures.

In the case of chronically tight Hamstrings postural pressures are generally the cause, unless you are an athlete but even then they can be part of the contributing factors. The Hamstrings cross two joints, the hip and the knee and just like our hip flexors, if we keep the muscles shortened for a long period of time they will think that length is the appropriate default. Sitting for long periods of time, where the knees a bent, will shorten the Hamstrings. Add to this leaning back into the chair which rolls the top of your pelvis back and brings the bottom forward and you have an even shorter muscle.

Standing posture is also important in Hamstring health. Slouching causes the low back to bow backwards and rolls the top of the pelvis back and the bottom forward and down, once again causing the Hamstrings the shorten.

As with any other muscle, the key to healthy Hamstrings is stretching, proper posture, and keeping moving. There are lots of ways to stretch the Hamstrings but these generally reaching down and touching your toes which many people find uncomfortable and difficult. So I’m going to share with you a different stretch that is a little easier for those of us, myself included, who are not all that athletic.

Lie on your back on a flat surface that you can comfortably stretch out on. Take a bath towel and fold it along the width to make it thinner but still the same length. Hook one heel in the middle of the towel and grab the ends of the towel in your hands. Pull your leg up, flexing and the hip and keeping your knee straight, until you feel the stretch along the back of your leg. Hold firmly onto the towel with both hands and resist as you push your heel into the towel as if trying to bring your heel back down to the floor. Your foot should not move during this push. Maintain the pressure for the length of 3 big belly breaths. Relax the pressure from your leg and gently pull your leg further up with the towel until you meet tension and feel the stretch in the back of the leg again. Hold this stretch for a count of 3 big belly breaths then push into the towel again. After 3 belly breaths of pushing relax and pull your leg towards you more. Repeat this process one more time until you have pushed and stretched 3 times each. After this push your heel back into the floor one last time and only resist this pressure with the towel half as much as you had before. This should allow your foot to slowly come back to the surface you are on. If you feel your Hamstrings are tight do this every morning for each leg and see the difference it will make.

So remember. Sit up straight, move often, and stretch daily.

Thanks for reading,
Dr. Ben

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