Men’s muscles may be larger than women’s, but when push comes to shove the male muscle wimps out a lot sooner, research shows.
When investigators at the University of Colorado at Boulder tested muscular endurance among 16 study participants, they found that women far outlasted men. The men and women had to perform two exercises that tested their elbow flexor muscles: one in which they held one of their arms in a rigid position for as long as possible, and another in which a weighted bag was added to the wrist. The exercises were akin to carrying groceries, lead researcher Dr. Sandra Hunter told Reuters Health.
Hunter’s team found that although the men were stronger, the women were able to hold the muscle contractions about 75% longer. In fact, Hunter said, one “big, burly guy” held the positions for only 3 minutes, while one woman held on for an hour and a half.
She presented the findings last week in Portland, Maine, at a meeting of the American Physiological Society.
Previous research has garnered similar results for various muscle groups, but the reasons for women’s greater endurance has been unclear. To shed some light on the issue, Hunter’s team measured the electrical activity in the participants’ muscles as they performed the exercises. There appeared to be no differences in men’s and women’s central nervous system activity.
Instead, Hunter said, women may have better blood flow to the muscles, making them less prone to tire quickly. Other findings from the study boost this theory: The women’s blood pressure and heart rates were lower than the men’s during the exercises. Because estrogen promotes blood flow, Hunter said, hormonal differences could explain endurance differences between women and men.
Studies have also shown that women outlast men during aerobic exercise. Again, Hunter said, estrogen may lend the advantage. The hormone seems to help the body conserve carbohydrates, so that women have more energy to draw upon late in the game.