Effects of additional resistance training during diet-induced weight loss on bone mineral density in overweight premenopausal women

Bone loss accompanies a diet-induced weight loss and could be prevented with a combination of exercises. This study was conducted to examine the effects of additional resistance training during diet-induced weight loss on whole-body and selected regional bone mineral density (BMD). The participants of a 14-week weight-loss study were 42 overweight premenopausal Japanese women who were randomly placed in either a diet-only group (D; n = 21) or a diet plus resistance training group (DR; n = 21). Whole-body BMD and body composition, lumbar spine BMD, and 1/3 radial BMD were measured by dual-energy X-ray absorptiometry before and after the intervention. Bone formation and resorption markers were also measured. Thirty-five participants (83%) completed the study. Individuals in groups D (n = 17) and DR (n = 18) lost 6.2 +/- 3.5 kg and 8.6 +/- 3.6 kg body weight, respectively. Reductions in percentage fat mass and fat mass in group DR were significantly greater than in group D; lean mass decreased significantly in both groups. The effect of time on whole-body BMD was significant (-0.3%); however, whole-body bone mineral content, lumbar spine BMD, and 1/3 radial BMD remained unchanged. There were no significant timeby-group interactions in the whole-body and regional BMD and bone markers. These results suggest that additional resistance training during weight loss has no effect on BMD in overweight premenopausal Japanese women. Further long-term studies with large numbers of subjects are needed.