The effects of resistance training on resting metabolic rates in overweight adults.

Abstract

The purpose of this study was to determine if resistance training (RT) aids in weight loss over time by increasing the fat free mass (FFM) and resting metabolic rate (RMR) in overweight subjects. This study included 6 sedentary, overweight male and female subjects between the ages of 19-33 years who participated in a 12-week intervention of RT or no exercise, and a 4-week post intervention of no exercise. Subjects were randomized into 1 of 2 groups: exercise ( n = 2), control (n = 4). RMR, FFM, fat mass (FM), body fat percentage (BF), bone mineral density (BMD), one repetition maximum on the leg and chest press, waist circumference, height, and weight were all measured before the intervention (time 1), after the intervention (time 2), and after the post intervention (time 3). Oxygen consumption was measured through open-circuit spirometry to determine RMR. FFM was measured on a GE Lunar iDXA bone density scanner. A repeated measures analysis of variance (ANOVA) with post hoc tests was conducted to determine significant differences between groups over time analysis. Effect size (d) calculations determined the magnitude of change. The exercise group showed no significant changes, whereas the control group indicated significant increases in FFM between times 1 and 2 (p = .006), and between times 1 and 3 (p = .001). The data from this study indicate that RT does not significantly increase RMR. However, the ES revealed a large change from time 1 to time 2 in RMR (d = .87) and a small change in FFM (d = .10) in the exercise group; whereas the control group had small changes in both RMR (d = .26) and FFM ( d = .36). The d suggests that RT may increase RMR without increasing FFM.