A new study conducted by USA Track & Field has found that stretching before a run causes no obvious harm, but offers no clear benefit, either.
The study, published on USATF's website last month and summarized this week in a New York Times blog, recruited nearly 1,400 runners ranging in age from 13 to 60-plus and randomly assigned them to two groups - one that engaged in static stretching before a run, and one that didn't. (Static stretching involved holding specific poses for 20 seconds each, for a total warm-up of three to five minutes). After three months of adhering to their assigned regimens (including identical running components), roughly 16 percent of the participants who stretched suffered injuries significant enough to keep them from running for three or more days, while a virtually identical percentage of non-stretchers were likewise laid up.
The USATF study did find that runners who were used to stretching before being assigned to the non-stretching group were injured at a disproportionally high rate: 23 percent over the three months. However, experts agree this didn't prove that stretching had protected these runners from injury in the past. Rather, their study-induced injuries likely resulted from the fact that any change in their training regimen had taken place.
The bulk of available science suggests that static stretching not only does nothing to prevent overuse injuries, but can actually hinder performance; the body's own reflex prevents muscles from stretching too much and thus they become tighter in a mode of self-protection. "The findings of this present study are totally in line with the existing literature," Malachy McHugh, the director of research at the Nicholas Institute of Sports Medicine and Athletic Trauma in New York, told the Times.
A better alternative to static stretching, experts say, is dynamic stretching, in which an easy warm-up builds in intensity until the joints' range of motion is enhanced through constant movement. Marching in place, as opposed to reaching down and touching one's toes, for example, engages the brain in proprioception and control, and results in increased flexibility.
