What Causes the Hamstring Muscles to Tighten or Shorten?

Tight hamstrings have an adverse effect on alignment.
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Four muscle bellies, originating at your pelvis and inserting at your lower leg, make up your hamstrings. Although famous for its knee-bending function, your hamstring group also extends your hip by moving your leg behind your body. When they tighten, your hamstrings nag like a chronically barking dog. Although stretching provides temporary relief, hamstring shortness is a complex, often mysterious problem that demands a whole-body approach.

Sitting and Your Hamstrings

    For most of us, our day begins when we sit down for breakfast and perhaps read the newspaper while we sip our morning coffee. Heading out to work, we sit in cars, buses or trains. After eight hours at our desks, we ride home, eat dinner and post on Facebook. Throughout all this sitting, our legs remain flexed. In response, our hamstrings tighten and beg for mercy. Meanwhile, our hip flexors, which connect the thighs and pelvis, shorten and cause a syndrome called reciprocal inhibition, which further complicates the hamstring tightening process.

Reciprocal Inhibition

    During any action, a main muscle, called the prime mover, performs the movement, an antagonist performs the opposing action and a group of synergistic muscles assist the prime mover. When your butt muscles assume the leading lady role, your hip flexors get cast as the opposition, while your hamstrings act as BFF to your glutes. If your hip flexors work so hard that they steal the show, your butt might decide that it's time for a vacation.

Synergistic Dominance

    When your butt decides to go on hiatus, she leaves her trusted friends, your hamstrings, in charge of the movement. This decision always ends badly. Your hamstring group gives superb performances when acting in supporting roles, but they fail as leading ladies. To do a job for which they lack sufficient strength, your hamstrings strain, struggle, shorten and eventually tear. Stretching your hamstrings only provides a band-aid and does not fix the problem. Stretching your hip flexors and strengthening your glutes offers a more holistic solution.


    Despite their undisputed sex appeal, high heels wreak havoc on your posture. When worn too often, they cause an anterior pelvic tilt.This posture arches your lower back and sticks out your butt. If the arch becomes extreme, it might trigger a scary variety of chronic lower-back problems. The tightening and shortening of your hamstrings is actually a protective mechanism, which keeps you from arching your back into the danger zone, explains Leon Chaitow, author of "Naturopathic Physical Medicine." Your instincts might tell you to stretch your hamstrings, but doing so does not solve the problem. Correcting your pelvic alignment through postural alignment techniques is a better alternative.

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