BLACKSBURG, Va., Aug. 9, 2000 -- Stress fractures are debilitating and costly, and they pose a serious problem for physically active military personnel. Female soldiers suffer these fractures along the tibia, or shin bone, at twice the rate of their male counterparts during training. These types of fractures erode physical capabilities and reduce effectiveness of combat training units, essentially compromising military readiness.
To combat this issue, the Army is providing a grant to Virginia Tech researchers to study the effects of specialized exercise on bones in young women. Bill Herbert, a professor in the Department of Human Nutrition, Foods, and Exercise, is the primary investigator on this project, which has yielded a grant of $739,421 from the Department of Defense.
The study will involve 160 women between the ages of 18 and 26. It will investigate the effects of 30 weeks of isokinetic resistance exercise on the non-dominant arms and legs of participants. The exercises do not employ free weights for resistance but use a special exercise machine, the Biodex®, which controls the speed of the working muscles, thus allowing expression of more force than free weights over the entire range of motion. The contrasting exercises in the study will be a concentric type (muscles shorten while contracting) or eccentric type (muscles lengthen as contraction occurs due to external force). These allow for different degrees of high but controlled force loading of the muscles and bones during training, and may promote the kind of bone strengthening that the investigators believe may help protect long bones from stress fracture.
A variety of measurements will be taken four times over the course of the study. A Mechanical Response Tissue Analyzer (MRTA), one of only a limited number of such machines in the world, will be used to gauge the stiffness of the arm and leg bones as the experiment progresses. The MRTA is loaded with software and algorithms specifically designed for this study. This machine painlessly measures the entire tibia or ulna using vibrations and sensors. The shape of a bone may be subject to change through the exercise training, and the reorganization of the bone matrix affects its overall strength. Participants will also have bone density and lean/fat mass measured by a DXA machine, a high-tech body scanner.
While this work has important implications for reducing stress fractures, it also has long-term implications for preserving bone mass and preventing osteoporosis in women. Shelly Nickols-Richardson, who has worked extensively with osteoporosis and nutrition studies, is co-principal investigator on the research team. Larnie Cross, a professor in Educational Leadership and Policy Studies, will assist in the statistics compilation, which includes a mind-boggling 471 variables. Other major players include Dr. Michael Slayton, a Blacksburg physician, who will function as the medical watchdog; Warren Ramp, Ph.D., formerly senior scientist of the Baxter Orthopedic Research Lab at the Carolinas Medical Center in Charlotte; and David Wootten, a clinical exercise physiologist who will serve as the project coordinator. In addition, five graduate assistant positions will be funded through this research.
"During my tenure here, I don¹t think there has ever been a funded human exercise research project of this magnitude," says Herbert, who is beginning his 30th year at Virginia Tech. "What really made this grant a success was our ability to assemble a talented multidisciplinary team with expertise in exercise physiology, nutrition, bone physiology, and statistics. In addition, we have had invaluable collaboration from long-term colleagues in the local medical community."
Appropriately, this study is referred to as the TiBIAL Trial, which corresponds to Trial in Bone Injury Abatement for Ladies. Learn more by visiting http://www.tibial.ed.vt.edu.
PR CONTACT: Jean Elliott
540-231-5915 elliottj@vt.edu