Title: Weight Lifted in Strength Training Predicts Bone Change in Postmenopausal Women
Abstract: CUSSLER, E. C., T. G. LOHMAN, S. B. GOING, L. B. HOUTKOOPER, L. L. METCALFE, H. G. FLINT-WAGNER, R. B. HARRIS, and P. J. TEIXEIRA. Weight Lifted in Strength Training Predicts Bone Change in Postmenopausal Women. Med. Sci. Sports Exerc., Vol. 35, No. 1, pp. 10–17, 2003. Purpose The aim of this study was to examine the relationship between weight lifted in 1 yr of progressive strength training and change in bone mineral density (BMD) in a group of calcium-replete, postmenopausal women. Methods As part of a large clinical trial, 140 calcium-supplemented women, 44–66 yr old, were randomized to a 1-yr progressive strength-training program. Half of the women were using hormone replacement therapy. Three times weekly, subjects completed two sets of six to eight repetitions in eight core exercises at 70–80% of one repetition maximum. BMD was measured at baseline and 1 yr. Results In multiple linear regression, the increase in femur trochanter (FT) BMD was positively related to total weight lifted (0.001 g·cm−2 for a SD of weight lifted, P < 0.01) after adjusting for age, baseline factors, HRT status, weight change, cohort, and fitness center. The weighted squats showed the strongest (0.002 g·cm−2 for a SD of weight lifted, P < 0.001), whereas the back extension exhibited the weakest (0.0005 g·cm−2 for a SD of weight lifted, P < 0.26) association with change in FT BMD. The amount of weight lifted in the weighted march exercise was significantly related to total body BMD (0.0006 g·cm−2 for a SD of weight lifted, P < 0.01). The associations between weight lifted and BMD for the femur neck or lumbar spine were not significant. Conclusion Evidence of a linear relationship between BMD change and total and exercise-specific weight lifted in a 1-yr strength-training program reinforces the positive association between this type of exercise and BMD in postmenopausal women.