Effect of Isokinetic Strength Training and Deconditioning on Bone Stiffness, Bone Density and Bone Turnover in Military-Aged Women

摘要

For physically active military personnel, stress fractures are debilitating and costly. Female soldiers sustain twice the number of stress fractures compared to males. Exercise interventions for women are needed to promote military readiness in ways that enhance bone strength and reduce stress fractures. This study, currently in progress, is investigating the effects of 30 weeks of concentric Vs eccentric isokinetic resistance training on bone stiffness (mechanical impedance), quality (mineral density and content), and bone cell activity (biomarkers of turnover). Female volunteers (N = 120), 18-26 years of age are categorized into normal bone density (NBD, n = 60) and low bone density (LBD, n = 60) subgroups, based on whole body bone density measurements. Subjects then are randomly assigned within NBD and LBD subgroups for concentric (n = 30 LBD, a = 30 NBD) and eccentric (n = 30 LBD, n = 30 NBD) exercise training. Exercises are performed using non-dominant arms and legs, leaving dominant limbs as self-controls. Results of this study will enhance understandings of effects of specialized exercise training on bone adaptations among young adult females. This work has important implications for reducing stress fractures arising from combat-readiness activities and for preventing osteoporosis in women.