AMC Outdoors, March 2008
Is one pre-exercise ritual a myth?
Time to get outside and play. So loosen those legs. Limber your upper body. Stretch out all the muscles you’ll use. If you’re like most health-conscious athletes, you routinely stretch key muscle groups before exercise to help reduce the chance of injury. But it turns out you might be wasting your time—there is no clear scientific evidence that pre-exercise stretching makes any difference, at least when it comes to injury prevention. So should you bother at all?
SURVEY SAYS In 2004, Dr. Julie Gilchrist, a medical epidemiologist at the Centers for Disease Control and Prevention (CDC), co-authored a review article that evaluated every available scientific study on pre-exercise stretching and its effects on injury prevention. After reviewing the collected literature, the paper concluded that “stretching was not significantly associated with a reduction in total injuries.” And though the study found no correlation between stretching and reduced injury rates, it didn’t find any evidence that stretching was harmful either. “There wasn’t sufficient evidence to indicate that it was helpful, or not helpful,” Gilchrist says. Part of the ambiguity resulted from a paucity of relevant studies. Of the 361 research papers considered for inclusion in the CDC report, only six directly measured the effects of pre-exercise stretching on injury. “The other thing this article was able to do was highlight some of the difficulties of researching this area,” she adds.
WORKING STIFF? Foremost among these difficulties is determining how an athlete’s flexibility and injury risk are related. “We know from military studies that those that are least flexible and most flexible have the highest injury rate,” Gilchrist explains. “That would theoretically indicate that a normal range of flexibility is important for injury prevention.” Dr. Ed Zambraski, military performance division chief at the U.S. Army Research Institute of Environmental Medicine in Natick, Mass., concurs. “People with low or high flexibility are more likely to become injured. But studies haven’t really looked at these particular groups.” Numerous studies have demonstrated, however, that stretching increases short-term flexibility, a potential benefit to athletes involved in sports that require extended range of motion, like whitewater kayaking or rock climbing, and a likely—though unproven—means to mitigate injury if you are unusually inflexible.
GETTING WARMER Ed McNeely is the co-founder of Strength Pro, a sports consulting business, and has worked with 17 different Canadian national teams, including rowing, biathlon, and cycling. Like many professional trainers, he remains convinced that pre-exercise stretching has its benefits. “There are two purposes for stretching: for warm-up and for flexibility. Stretching won’t prevent joint or skeletal injury,” McNeely claims. “But there’s quite a bit of good evidence that stretching can help prevent muscular injury.” Despite the lack of conclusive science supporting this assertion, McNeely does have a point. Research has shown that a good pre-exercise warm-up—which can include stretching as one of its components—can be beneficial. The key is to realize that stretching by itself doesn’t count as a full warm-up.
JUST DO IT To warm up properly, you need to get your heart pumping through a low-intensity cardio activity that focuses on the muscles appropriate to your intended activity. “A good warm-up raises your heart rate and increases blood flow to your muscles through the range of motion you expect to need,” Gilchrist explains. “Warm-ups have been shown to prevent injuries. If you only have five minutes, it might be more important to focus on a really good warm-up than to focus on the muscles.” As part of the process, McNeely advocates a slow start to your activity. “Work into it easy. Spend the first 5-10 minutes going at 75 percent of pace you plan on using.” But all this advice doesn’t mean you should stop stretching, especially if it’s something you enjoy. “There’s no negative effect to stretching,” Zambraski notes. “Even if it doesn’t change the injury rate, it’s sort of like, ‘If it doesn’t hurt me, I’m going to do it.’”
-By Matt Heid
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