The Downside to Stretching Muscles

Balance, reaction, movement time impaired in Canadian study

Reviewed by Brunilda Nazario, MD on August 27, 2004

Aug. 19, 2004 -- Stretching your muscles before exercise may not give you the edge you expect.

Canadian researchers at the University of Newfoundland put stretching to the test in a recent study published in Medicine & Science in Sports & Exercise, the journal of the American College of Sports Medicine.

The study had a small number of participants -- 16 healthy male college students.

Led by David Behm, PhD, the researchers started the experiment by having all the participants warm up with a ride on a stationary bike for five minutes.

Next, some of the students stretched certain leg muscles.

They stretched to the point of discomfort, holding each stretch for 45 seconds without bouncing. The stretches were performed three times, with 15-second rest breaks between stretches.

Meanwhile, the students in the comparison group had it easier. They didn't stretch at all. Instead, they were allowed to rest for about 26 minutes after their five minutes of cycling.

Afterward, all the students were tested to measure their leg extension force, balance, reaction time, and movement time.

Researchers used special equipment, including a wobble board, to gauge any differences between the two groups.

Balance, reaction time, and movement time were better in the students who hadn't stretched.

The differences were "low but significant percentage changes," write the researchers, who say the reason may be that stretching changes muscle compliance.

Though the gaps weren't large, it might make a difference to elite athletes seeking the slightest competitive advantage or to elderly people with balance and stability problems.

There was no significant difference in force output between the two groups.

If you stretch to improve your flexibility, there's no reason to stop. This study didn't examine whether stretching affected flexibility.

Show Sources

SOURCE: Behm, D. Medicine & Science in Sports & Exercise, August 2004; vol 36: pp 1397-1402.

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