Most runners, whether they’re training for a marathon or simply out to get some exercise, will stretch before they take off. It’s a ritual that verges on the sacred, strongly connected to the intuitive sense that priming the muscles is a good way to avoid injuring them during the run to come.
But researchers at George Washington University and the USA Track and Field Association (USATF) report that stretching before a run does not appear to reduce injury at all. In fact, among the more than 2,700 runners in the study, ranging from recreational runners to competitive marathoners, all of whom ran at least 10 miles a week, the scientists found similar injury rates — of about 16% — over a three-month period among those who stretched before running and those who did not.
The idea behind stretching is to lengthen the muscle fibers to increase their function and hopefully enhance performance, helping runners maintain a faster pace or run for a longer period of time. A study of British recruits in the military found that a regular stretching routine before training reduced injury rates from 6% to 1%. But other recent studies among gymnasts, football players and wrestlers have questioned the practice, suggesting that stretching does not impact performance at all.
That’s why Dr. Daniel Pereles, a runner himself, decided to look specifically at the role that stretching might play in running injuries. Most studies on the subject, including the British trial in the military, involved stretching routines that included much more than stretching running muscles; they also incorporated calisthenics and other exercises. Pereles wanted to know specifically whether stretching leg muscles — the quadriceps, hamstrings and calf muscles — would have an impact on injuries.
Through the USATF, Pereles was able to recruit enough runners of various levels to get an answer to his question. About half of the 2,729 volunteers were told to stretch their quads, hams and calf muscles for three to five minutes before running for however long they usually exercised. The remaining half were told to run without stretching.
While he found that stretching did not have any effect on injury rates among the two groups, he did find several factors that did seem to influence whether the runners hurt themselves. Heavier runners, as well as those who had recently suffered an injury, were more likely to harm themselves. Interestingly, Pereles also found that those who switched from a stretch to non-stretch or non-stretch to stretch routine for the study were more likely to get injured. Stretchers who were told not to stretch during the three-month study increased their risk of injury by 40%, while those who switched from not stretching to stretching increased their risk by 22%.
Pereles is still at a loss to explain that trend, although he suspects the change in routine accounts for most of the result. “It’s completely confounding, but by switching routines, it somehow messed them up,” he says.
That’s why his advice, as both researcher and runner, is to stick with what works for you. “If it feels good for you to stretch before you run, then continue if you have the time,” he says. “But if it doesn’t feel good, and you like to run and then stretch, or not stretch at all, then that’s fine too. I can’t tell anyone there is conclusive evidence that stretching makes a difference in injuries or performance.”
He notes that professional athletes, who often spend as much time stretching and warming up as they do training, are combining stretching with other activities for a more dynamic warm-up. Most recreational runners, however, don’t have the luxury of spending that much time exercising. Pereles himself admits to changing his running routine as well, and stretching only a little before a run. Part of the reason, he says, is because he doesn’t have the time, and but part of the reason has to do with the science, which so far suggests that it doesn’t seem to make a difference in injury rates.