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Name: Sally
Status: educator
Grade: 9-12
Location: IA
Country: N/A
Date: April 2006

I was resently told by a colleague that male and female muscles are different. Female muscle fibers run horizontally and male fibers run vertically. This is why female form cellulite. Is there any evidence for this position?

Dear colleague,

Interesting question. When I read it I was pretty sure that your colleague was mistaken, and I still think so. I consulted with a colleague of mine here at my university, who is something of an expert on anatomy and physiology. Here's what he had to say, with some editing (and if there are mistakes I introduced inadvertently due to the editing they're all my fault):

No, there is no evidence for such a position. Do all females form cellulite (deposits of fat and fibrous connective tissue )?...... of course, the answer is no. Women's fat lobules tend to be larger and more rectangular than men's and their septae run vertical to the surface of the skin rather than diagonal ( note: we are talking about the septae that separate the lobules, not muscle fibers ). Therefore, fat becomes trapped more easily in women. Many factors are involved in forming cellulite..... poor blood circulation, poor lymphatic flow, changes in estrogen and progesterone, genetic factors, eating foods with an overabundance of sugar etc.

Best, dr. topper

Your colleague is way off. The muscle fibers run the same direction (vertically). If they ran horizontally, the muscles would not work! It is the stretching and contracting of these fibers that make the muscles work the way they do. Males have higher levels of the hormone testosterone, which directly increases size and mass of muscles, vocal cords, and bones, enhancing strength, deepening the voice, and changing the shape of the face and skeleton. females have higher levels of the hormone estrogen which widens the pelvis and increases the amount of body fat in hips, thighs, buttocks, and breasts. So in conclusion, the muscles don't make the difference between males and females, the hormones do. This is why some athletes will elegally take testosterone medication to increase their strength.

Grace Fields

Hi Sally!

Not at all!

The physiology in the muscular system is equal in both sexes and the differences existing are due to size and limited also by the differences that exist in the skeleton and organ in the human sexes.

In fact recent research found that: Data suggest that the greater strength of the men was due primarily to larger fibers. The greater gender difference in upper body strength can probably be attributed to the fact that women tend to have a lower proportion of their lean tissue distributed in the upper body. It is difficult to determine the extent to which the larger fibers in men represent a true biological difference rather that a difference in physical activity, but these data suggest that it is largely an innate gender difference.

Thanks for asking NEWTON!

(Dr. Mabel Rodrigues)

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