UIC researcher to investigate whether mechanical forces can increase bone strength

Bone strength is important to aging well, but doctors and therapists are far from understanding the best way to maintain healthy bone or what kind of exercise might help, according to University of Illinois at Chicago College of Applied Health Sciences researcher Karen Troy.

The National Institutes of Health has awarded Troy a four-year, $1.6 million grant to investigate whether mechanical forces applied to bone can increase bone strength.

Studies in animals show changes in bone structure following application of well-defined forces, says Troy, UIC assistant professor of kinesiology and nutrition. The problem is how to apply strain to bone in people in ways that will result in growth and strength.

"The principles from animal [studies] seem to carry over, but we don't know how exactly to implement them," Troy said. "The long-term goal is understanding how we can use physical-activity interventions to improve bone health, prevent fractures, and prevent or treat osteoporosis."

Troy and her colleagues will recruit women who will apply force to the radius, one of the large bones of the forearm, by pressing the palm of their hand onto an apparatus that measures the force and speed of the pressure.

Two studies will test how bone adapts to different forces. In one study, one group will apply light pressure and another group will apply heavier pressure to determine if there is a dose response in bone changes -- that is, if more pressure results in more growth. In a second study, subjects will apply pressure at high or low rates. The women will apply pressure three times a week for 12 months.

Changes in bone will be determined by quantitative computed tomography, a three-dimensional X-ray technique that will reveal very fine changes in mineral density and structure.

Participants will be followed for an additional 12 months to see how they retain bone changes.

"We know that ordinarily people may not exercise consistently," Troy said.

Troy hopes to obtain results that translate into "how many times I would have to do an exercise to get this much bone growth, on average, in a particular person over a particular time period," she said.

"Our long-term goal is to be able to design a personalized physical activity intervention that would specifically target bone health."