Wednesday, September 8, 2010

Stretching Before Running May Lower Endurance


Stretching Linked to Shorter Running Distance and Higher Energy Expenditure

Distance runners who stretch before running may not be able to run as far—and yet spend more energy doing it, according to a study in The Journal of Strength and Conditioning, official research journal of the National Strength and Conditioning Association. The journal is published by Lippincott Williams Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, and pharmacy.

"Our results suggest that stretching before an endurance event may lower endurance performance and increase the energy cost of running," write Jacob M. Wilson, PhD, CSCS, and colleagues of The Florida State University, Tallahassee.__Static Stretching Leads to Decreased Running Performance_Ten male collegiate runners performed a 60-minute treadmill run on two different occasions: once after stretching and once without stretching. The 16-minute stretching regimen consisted of static stretching—stretching a muscle to its maximum length and holding it—of the major muscles of the lower body. The sessions were performed in random order. At each time, the runners were instructed to run as far as possible; however, they were unable to view their running distance or speed.

Running distance was actually shorter without stretching. When the runners stretched, their average running distance was 3.4 percent less than when they ran without stretching.

Even though the athletes covered less distance, the energy cost of running was significantly greater after stretching. On average, the runners burned about five percent more calories in the run performed after static stretching.

Stretching has long been a part of the warm-up routine for runners and athletes in other sports. However, recent studies have suggested that static stretching may actually have some negative effects. These effects—particularly reduced muscle-tendon stiffness and reduced muscle strength—could have a negative impact on running performance.

The new results suggest that stretching before running reduces endurance while increasing energy expenditure. The differences may not seem great—on average, running distance decreased by 0.2 kilometer after stretching while energy expenditure increased by 20 calories. However, for highly trained runners, those differences are more than enough to affect competitive performance.

Building on previous studies showing negative effects on muscle strength, the new results suggest that static stretching may reduce endurance performance as well. "Therefore, static stretching should be avoided before endurance events, at least for young male endurance athletes," Wilson and colleagues write. They call for more research to clarify how static stretching affects muscle performance, as well as to evaluate the effects of other types of stretching—particularly dynamic stretching.

No comments: