Pre-Run Stretch May Hurt Endurance
Runners Who Stretched Expended More Energy, Ran Shorter Distances, Study Finds
Sept. 10, 2010 -- Some runners swear by their pre-run stretch as a sure-fire way to run better and stronger and reduce their risk of injury in the process.
But according to a new study, distance runners who stretch before a run may not perform as well and may spend more energy than runners who skip the stretch.
''Overall, I don’t think it's worth it to stretch before a run," researcher Jacob M. Wilson, PhD, assistant professor of exercise science and sport studies at the University of Tampa, tells WebMD. "After a run, if someone is trying to work on flexibility, that's fine."
Although his study was done only on male runners who were young and highly trained, Wilson speculates that the findings would apply to recreational runners and to female runners as well.
The study is published in the Journal of Strength and Conditioning Research.
Stretching Before a Run: The Study
Wilson evaluated 10 runners, all men, who were on average 25 years old. They were in good shape with a low percent of body fat -- just under 7%, on average.
All runners participated in a 60-minute treadmill run on two different days separated by at least one week. One time, they stretched for 16 minutes before running and the other time they just sat quietly for the same time period.
The pre-run stretches were static -- stretching a muscle to the maximum length and holding it -- and included all the major muscle groups of the lower body.
After the stretching or the sitting, the runners did a 30-minute warm-up run, then a 30-minute performance run. Each time, the runners were told to run as far as possible during the performance part, but they couldn't see distance or speed on the treadmill display panel.
Without stretching, the runners averaged 6 kilometers or 3.7 miles in the half-hour performance run, Wilson tells WebMD. With stretching, they averaged 5.8 km or 3.6 miles, a difference of 3.4%.While the difference seems small, it could add up during a competitive event.
"One of the reasons why stretching impairs performance is it probably causes muscle damage," Wilson says, referring to tiny, micro tears.
Previous research by others has looked at stretching and the effects on sprinting or vertical jumping, Wilson says. "Ninety percent have found declines in performance."
He says that "ours is one of the first to look at stretching and endurance performance, and we saw decrements."
Stretching also resulted in a higher number of calories burned. When runners stretched before they ran, they burned 425 calories, on average, during the warm-up run. When they didn't stretch, they burned 405 calories, on average.
Stretching and Performance
Whether to stretch before running or not is ''an individual choice," says Ryan Lamppa, a spokesman for Running USA, which promotes the growth of the U.S. running industry. He has coached distance runners and is a runner.