A Six Month Minimal Resistance Training Program Improves Energy Expenditure And Fat Oxidation In Sedentary, Overweight Young Adults Measured Using A Whole Room Indirect Calorimeter

Abstract

Resistance training (RT) may increase 24-hr energy expenditure (EE) and fat oxidation to a level sufficient to assist in maintaining energy balance and prevent weight gain; however, the impact of a minimal RT program (1 set, 3 d/wk, 3-6 repetition maximum, 9 exercises) on these parameters is unknown. PURPOSE: Therefore the purpose of this investigation was to evaluate the effect of 6-months of supervised minimal RT in previously sedentary, overweight (mean ± SD, BMI =27.7 ± 2.9) young adults (21.0±2.2yrs) on 24-hr EE, resting metabolic rate (RMR), sleep metabolic rate (SMR) and respiratory quotient (RQ) assessed by whole room indirect calorimetry. METHODS: Participants were randomized to RT (N=22, 16 Male (M), 6 Female (F) ) or control (C, N=17, 11M, 6 F) groups and completed assessments of 24-hr EE, RMR, SMR and RQ at baseline and 6 months (72 h after the last RT session for RT group) and maximal strength (1- repetition maximum: chest press, leg press). Both groups maintained their normal ad-libitum diet and activities of daily living. RESULTS: Results indicated significantly greater increases (p < 0.0001) in both chest (RT = 47.5 ±22.9 %) and leg press (RT = 53.7±40.0%)strength in RT compared with C. Twenty-four hour EE increased in both RT and C groups with a non-significant trend toward larger increases in RT (4.0±5.1%) compared with C (2.1±5.6%). The difference in change in RMR between RT and C groups was non-significant (p = 0.095); however, RMR increased significantly in the RT group (7.4±8.7%, p<0.001). There was a non-significant trend for a decrease in RMR-RQ for RT (−1.5±5.2) with a slight increase in C (0.4±5.2). The increase in SMR was significantly (p=0.016) greater in RT (7.7±8.6%) compared with C (1.0±8.7%). Sleep RQ was essentially unchanged in C (0.7±3.6%) and decreased significantly in RT (-1.7±2.7%, p =0.005), resulting in a significant difference in change in sleep RQ between groups (p=0.034). CONCLUSIONS: These results suggest that a minimal RT program, requiring little time to complete (11 min per session) may have a favorable impact on energy balance and fat oxidation, and assist with the prevention of obesity in sedentary, overweight, young adults.