Effect of Isokinetic Strength Training and Deconditioning on Bone Stiffness, Bone Mineral 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), bone quality (mineral density and content), and bone cell activity (biomarkers of turnover). Female volunteers (N = 120), 18-26 years of age have been categorized into normal bone density (NBD, N = 60) and low bone density (LBD, N = 60) subgroups, based on whole body bone density measurements. Subjects subsequently have been randomly assigned within NBD and LBD subgroups for either concentric (n = 30 LBD, n = 30 NBD) and eccentric (N = 30 LBD, N = 30 NBD) isokinetic exercise training. Exercises are performed using non-dominant arms and legs only, leaving dominant limbs as self-controls Results of this study will enhance understandings of effects of specialized isokinetic resistance exercise training on bone adaptations among young adult females. This work has important implications for reducing stress fractures arising from combat- readiness activities in women and their risks for future osteoporosis.