Strength training and adiposity in premenopausal women: Strong, Healthy, and Empowered study

Background: American women aged 25-44 y gain 0.5-1 kg yearly, most of which is fat. Because few midlife women participate in strength training, this mode of activity may be a novel intervention for preventing age-associated fat increases in this population. Objectives: The primary aim was to assess the efficacy of twice-weekly strength training to avoid increases in percentage body fat and intraabdominal fat. Design: A randomized controlled trial was conducted in an ethnically diverse sample of 164 overweight and obese [body mass index (in kg/m²): 25-35] women aged 25-44 y. The treatment group did twice-weekly strength training for 2 y. The standard care comparison group was given brochures recommending aerobic exercise. Assessments at baseline, 1, and 2 y included intraabdominal fat by computed tomography scan and body fat and fat-free mass by dual-energy X-ray absorptiometry. Results: During 2 y, percentage body fat changes were -3.68 ± 0.99% for the treatment group and -0.14 ± 1.04% for the control group, P = 0.01. Two-year intraabdominal fat changes were 7.05 ± 5.07% for the treatment group and 21.36 ± 5.34% for the control group, P = 0.05. Conclusion: This study suggests that strength training is an efficacious intervention for preventing percentage body fat increases and attenuating intraabdominal fat increases in overweight and obese premenopausal women. This is relevant to public health efforts for obesity prevention because most weight gain can be assumed to be fat, including abdominal fat.