The Effect of Sprint Interval Training on Body Composition of Postmenopausal Women.

INTRODUCTION: Menopause is accompanied by body composition changes that include a decrease in lean mass and aerobic fitness and an increase in fat mass. Sprint interval training (SIT) may be able to reverse these changes. PURPOSE: To examine the effect of an 8-wk SIT program on body composition and aerobic fitness of overweight postmenopausal women. METHODS: Forty postmenopausal women were randomized into SIT (n = 20) or control (n = 20) groups. The SIT group completed three SIT sessions a week for 8 wk with each session consisting of 20 min of alternating 8-s sprints and 12-s of light pedaling. Total mass, regional lean mass, and fat mass were assessed using dual-energy x-ray absorptiometry. Maximal oxygen uptake (V˙O2max) was predicted using a submaximal test. RESULTS: Total lean mass was significantly increased from pretest (48.1 ± 5.81 kg) to posttest (48.8 ± 5.96 kg) and fat mass was significantly reduced (pre, 29.5 ± 7.29 kg; post, 29.1 ± 7.61 kg) for the SIT group. Lean mass was mostly increased in the trunk (pre, 24.4 ± 2.79 kg; post, 24.8 ± 2.93 kg) and legs (pre, 15.6 ± 2.31 kg; post, 15.9 ± 2.34 kg). V˙O2max was significantly increased from pretest (21.7 ± 4.89 mL⋅kg⋅min) to posttest (24.4 ± 5.96 mL⋅kg⋅min) for the SIT group only. CONCLUSIONS: The SIT intervention increased total lean mass, decreased fat mass, and increased aerobic fitness of postmenopausal women after only 8 h of actual exercise over 8 wk.