A little stretching may not dampen muscle strength

While some research has raised the question of whether pre-workout stretching hinders muscle performance, a new study suggests that a few minutes of stretching may not sap the average exerciser's muscle strength.

Stretching is part of many active people's pre-exercise routine. But some recent studies have been pointing to potentially negative effects on athletic performance.

In some studies, though not all, stretching right before a workout has been found to decrease both sprint speed and jump height. There's also evidence that stretching temporarily reduces muscle strength.

However, one question has been whether such effects would be seen after the short bouts of stretching that a typical exerciser or weekend athlete might perform.

The new study, published in the journal Medicine & Science in Sports & Exercise, looked at just such a "practical" stretching regimen.

Researchers measured calf-muscle strength in 13 moderately active men and women under four different conditions: after no stretching, and before and after 2, 4 or 8 minutes of calf-muscle stretching.

They found that stretching did not diminish the participants' muscle strength compared with the no-stretching condition. It did, however, temporarily improve the range of motion in the ankle joint.

The findings suggest that "a few minutes of static stretching of the calf muscles before exercise is unlikely to diminish muscle strength," senior researcher Dr. Joel T. Cramer, of the University of Oklahoma in Norman, told Reuters Health.

Past studies, he noted, have shown that longer, less practical stretching regimens may in fact dampen calf muscle strength for a short time. "However," Cramer said, "most exercisers do not continuously stretch their calves for 10, 20 or 30 minutes."

It is possible that other muscle groups respond differently to stretching than the calf muscles do, according to Cramer. For instance, the quadriceps and hamstrings - muscles in the front and back of the thighs, respectively - may be more susceptible to the strength-sapping effects of stretching.

More studies are needed to answer that question, Cramer said.

Another limitation of the current study is that it included only moderately active people - not athletes, who might be more affected by small changes in muscle strength or power brought on by pre-competition stretching.

None of this means that stretching is not useful to active people. As demonstrated in the current study, stretching can improve joint range of motion in the short term. And some studies suggest that over the long term, a regular stretching regimen can help build muscle strength.