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Do Dense Bones Mean Strong Bones?

Posted March 12, 2008 at 03:00 PM by Katie Drummond

Section: Her Fitness, Her Health, Her News

Women Racing As a woman, you might spend a lot of time worrying and wondering about your bone density, with talk of osteoporosis and bone loss all over health magazines and television programs. Hopefully, you already use exercise as one means of staving off bone loss. But what are the differences between bone strength and bone density? And can you know about one by measuring the other? For a clarification of the differences, read this report from Dr. Gabe Mirkin.

The greater the force you put on your bones during exercise, the stronger they become.

Researchers at the University of Missouri in Columbia showed that recreational runners have denser bones than cyclists (Journal of Metabolism, February 2008). Another study from Université de St-Etienne in France show that youth soccer players have an increase in bone density over three years of playing high level soccer (Joint Bone Spine, January 2008). They failed to show that the soccer players had denser bones than their classmates, yet their intuition told them that heavy forces on bones while playing soccer must strengthen bones, so they stated that “The yearly gain in bone density is greater in soccer players than in controls.”

These studies and many others comparing various sports measure bone density, not bone strength. The only way to measure bone strength is to see how much force it takes to break them. Needless to say, nobody is doing these studies in humans. So scientists use bone density, which can be measured, as a substitute for measuring bone strength.

Nobody has shown that bone density determines bone strength. For example, birds have bones that are not dense because they need a low weight to fly effectively. Yet their bones are very strong. I think that, in the future, methods will be developed to determine bone strength and they will show that measuring bone density is, at best, a crude measure of whether a person is likely to break his or her bones.

Dr. Mirkin is board certified in Sports Medicine and has practiced for over 40 years. He has completed more than 40 marathons and was a talk show host of a nationally-syndicated radio program for about 25 years. For more articles by Dr. Mirkin, click here.