Bone Abstracts

Although trials have shown that exercise has positive effects on bone mineral density (BMD), not all exercise modalities are osteogenic and the majority of exercise trials have been conducted in older women. The aim of this study was to systematically review trials examining the effect of weight-bearing and resistance-based exercise modalities on the BMD of hip and lumbar spine of middle-aged and older men. Eight electronic databases were searched in August 2012. Only randomised controlled or controlled trials that assessed the effect of weight-bearing exercise interventions on bone density measured by dual-energy X-ray absorptiometry (DXA), and reported effects in middle-aged and older men were included in this review. Eight trials detailed in nine papers were included. The interventions included yoga (n=1), walking (n=2), resistance training (n=6) and impact-loading activities (n=1). The methodological quality and reporting of five out of the eight trials was poor. Further, there was heterogeneity in the type, intensity, frequency and duration of the exercise regimens. Effects of exercise varied greatly among studies, with six interventions having a positive effect on BMD, but two interventions having no significant effect. Nevertheless, it seems that resistance training and impact-loading activities are most osteogenic for this population, whereas walking alone had little or no positive effect on bone density. Therefore, regular resistance training and impact-loading activities should be considered as a strategy to prevent osteoporosis in middle-aged and older men. Further high quality randomised controlled trials are needed to establish the optimal exercise prescription for improving BMD for this population.