slacker's posts
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As the articles in this month’s Medicine & Science in Sports & Exercise make clear, scientists actually seem to be becoming less certain about how exercise affects bone.
many scientists now think that that process doesn’t apply to bones. “If you stretch bone cells” in a Petri dish, says Alexander G. Robling, an assistant professor in the department of anatomy and cell biology at Indiana University School of Medicine and the author of an article in Medicine & Science in Sports & Exercise, “you have to stretch them so far to get a response that the bone would break.”
So he and many other researchers now maintain that bone receives the message to strengthen itself in response to exercise by a different means. He says that during certain types of exercise, the bone bends, but this doesn’t stretch cells; it squeezes fluids from one part of the bone matrix to another. The extra fluid inspires the cells bathed with it to respond by adding denser bone.
the current state-of-the-science message about exercise and bone building may be that, silly as it sounds, the best exercise is to simply jump up and down, for as long as the downstairs neighbor will tolerate. “Jumping is great, if your bones are strong enough to begin with,” Dr. Barry says.
If hopping seems an undignified exercise regimen, bear in mind that it has one additional benefit: It tends to aid in balance, which may be as important as bone strength in keeping fractures at bay.
From: Phys Ed: The Best Exercises for Healthy Bones - Well Blog - NYTimes.com 1
