WOMEN HAVE LONGER ENDURANCE TIMES THAN MEN FOR CERTAIN EXERCISES

 When performing certain isometric exercises, the endurance of women is almost twice that of men performing the same exercises; results being presented at a meeting on exercise and physiology by international scientists during Olympics

Portland, ME — A number of studies have found that women are capable of longer endurance times than men when performing certain isometric exercises at the same percent of maximum strength. A recent study conducted at the University of Colorado confirms those findings for different tasks, says Sandra Hunter, Ph.D., and expands on the reasons for the difference.

Dr. Hunter is a Postdoctoral Research Associate in the Neural Control of Movement Laboratory directed by Professor Roger Enoka, in the Department of Kinesiology and Applied Physiology, at the University of Colorado in Boulder. She will discuss the results of the research study at the American Physiological Society's intersociety meeting, “The Integrative Biology of Exercise,” being held from September 20-23, 2000 in Portland, ME.

Background: Dr. Hunter's purpose was to compare the endurance times—or fatigability—of men and women for two types of low-force exercises using the elbow flexor muscles. Eight men and eight women were asked to perform two isometric fatiguing contractions on separate days. In one task, the subjects were asked to hold their arm in a rigid position (within a restraint) for as long as possible. In the second task, a weight bag was added to the wrist, and the subjects were once again asked to hold their arm in the same position for as long as possible.

Results: Results of the study demonstrated that women outlasted the men by an average of 75 percent for both tasks. Importantly, the study showed that the reason the women had longer endurance times was not due to differences in the motivation levels between men and women, or within the nervous system, but due to differences within the muscle.

Because the weaker subjects had longer endurance times, and women were weaker than men, the specific reason for the gender difference in endurance time may be an interaction between muscle strength and blood flow within the muscle.  However, other possible reasons may include the type of muscle fibers of men and women or even the differences in hormones between men and women such as estrogen.

"While there is much known about the effects of estrogen," says Dr. Hunter, "there is just as much that we're not aware of in terms of its effect on women's bodies."

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Physiology research in exercise has been responsible for demonstrating that women are physiologically capable of running the marathon without the event being detrimental to their health and well being; the necessity of competing in a hydrated state, seeking frequent fluid replacement during endurance events; being acclimatized to heat before competition; scheduling competition in the early or late hours of the day; and providing fluids that contain a fixed concentration of glucose during the long distance events; the advantages to athletes -- particularly swimmers -- of tapering in their training before competition; the importance of the specificity concept in athletic training schedules and the acceptance by coaches of team sports (basketball and volleyball, among others) that specific power and strength training principles must be followed to enhance performance. The American Physiological Society is devoted to fostering scientific research, education, and the dissemination of scientific information. By providing a spectrum of physiological information, the Society plays a significant role in the progress of science and the advancement of knowledge.

Editor's Note: For further information or to schedule an interview, contact Donna Krupa at 703.527.7357; cell: 703.967.2751; or at djkrupa1@aol.com; or visit the APS website at www.the-aps.org.