CHANGES IN BODY COMPOSITION AFTER 1 YEAR OF RESISTANCE AND WEIGHT-BEARING EXERCISE IN PREVIOUSLY SEDENTARY POST-MENOPAUSAL WOMEN

Abstract

Two-hundred and forty-one sedentary post-menopausal women (age, 55.2 ± 4.8 y, body fat (%BF), 38.4 ± 6.7%) were randomly assigned to a control (n = 116) or an exercise group (n = 125). Exercisers performed supervised high-intensity resistance exercises (75–85% 1RM) 3 times a week for one year. Whole-body and regional lean soft tissue mass (LST), fat mass (FM), and %BF changes were measured twice (at baseline and 12 months) by DXA. In the training group, mean compliance to training sessions was 77.0% and subjects increased their strength by 41.8% ± 17.9% (average of 1RM tests in 6 core strength exercises). Exercisers had significant increases in whole-body LST (2.2%, p < 0.001), and leg, arm, and trunk lean masses (1.9%, 3.3%, and 2.5% respectively, p < 0.001). Changes in whole-body (−1.6%) and leg FM (−3.3%) in the training group were significantly different (p < 0.05) from changes in the control group (+0.8% and −1.0%, respectively). Weight did not change in any group (p > 0.05) while %BF regression analysis, group assignment was the only significant predictor of changes in body composition, in a model including age, baseline body composition, hormone-replacement therapy (HRT) status, and year past menopause. In the training group, total weight lifted (TWL) during 1 year of strength training significantly correlated with changed in LST (r = 0.36, p < 0.001), after controlling for age and baseline LST. A linear does-response relationship between the two variables described the relationship the best. For changes in FM relationship between TWL and FM change after adjusting for baseline FM and age was not significant (p > 0.05). We conclude that one year of resistance training has significant and positive effects on the LST and body composition of post-menopausal women, independent of weight loss, HRT, and number of year after menopause. The magnitude of weight lifted after one year reflects linearly on increases in lean tissue, as measured by DXA. Supported by NIH AR 39559 and Mission Pharmacal