Influence of resistance exercise volume on recovery energy expenditure in women

The acute effects of resistance exercise on energy expenditure in the post-exercise period have not been well studied in women, even though they are at high risk for weight gain and so would benefit greatly from exercise-related increases in energy expenditure. The purpose of this study was to identify factors that influence recovery energy expenditure in women after an acute bout of resistance exercise. Seventeen healthy women aged 40-55 years completed an acute bout of resistance exercise followed by measurement of energy expenditure for 120 min of recovery. Body composition was measured via air displacement plethysmography. The resistance exercise bout consisted of three sets of 8-12 repetitions of eight exercises at 50% of one-repetition maximum (1-RM) for the first set and 80% 1-RM for the second and third sets. Oxygen consumption (VO₂) was measured before and for 120 min after resistance exercise. Post-exercise energy expenditure data were analysed as 4-min means at 0, 20, 40, 60, 90, and 120 min of recovery. Mean (±s_x) training volume was 7604.1 ± 450.64 kg and overall mean recovery energy expenditure was 133 ± 6 kcal. Pearson's correlation analysis found no significant relationship between post-exercise energy expenditure and age, body mass index, exercise time or delay between cessation of exercise and commencement of metabolic measurement. Absolute (kg) lean mass was also not significantly related to energy expenditure at any time post-exercise, although relative (%) lean mass was during the late recovery period only (40 min of recovery: r = 0.49, P = 0.05; 60 min: r = 0.51, P = 0.04; 90 min: r = 0.63, P < 0.01). The factor most consistently related to post-exercise energy expenditure was total exercise volume, which had a moderately strong relationship through 90 min of the recovery period (0 min of recovery: r=0.49. P = 0.05; 20 min: r = 0.52, P = 0.03; 40 min: r = 0.53, P = 0.03; 60 min: r = 0.50, P = 0.04; 90 min: r=0.48, P = 0.05). In the present sample of women, acute post-exercise energy expenditure was influenced primarily by total training volume, although lean mass had a limited effect. Based on these findings, it is recommended that women be encouraged to lift at higher intensities (70-80% 1-RM) to maximize post-exercise energy expenditure and potentially promote fat loss.