Improved hamstring flexibility.

Avoiding a running injury may seem like a matter of chance. Some runners seem to have more resilient bodies. While that may be partially true, there are many ways you can conscientiously avoid injury. Frequently heard advice includes maintaining flexibility. A recent study involving military trainees confirmed that hamstring flexibility affects the rate of injury during a basic training course.

Nearly 300 trainees were divided into either one of two groups for basic training. One group was given minimal hamstring stretching as part of their training. The other had an additional three daily sessions of hamstring stretching. The results were fairly dramatic. The stretching group not only improved flexibility significantly, they also suffered fewer lower leg injuries. Incidence of injury in the stretchers was about 17% compared to the the non-stretchers, whose injury rate was over 29%.

Although this study could not be double-blinded or placebo-controlled, the resulting numbers are pretty compelling. Basic training may not be the same as running, but it certainly includes running along with other physical challenges. So despite those disclaimers, the research confirms the advice that runners are always given. Stretch--both after a warm up and after your run. This study may back up even stronger advice--increase your flexibility. Attend not only to stretching before and after a run, but treat your flexibility as a training objective in its own right. Runners should make sure to stretch the posterior muscles and tendons in particular: the hamstrings, along with calves, Achilles, quadriceps, and back muscles. And don't neglect to stretch the hip flexors and the iliotibial band. (American Journal of Sports Medicine, 1999, Vol. 27, No. 2, pp. 173-176)