Effect of Training Status on Energy Expenditure after Resistance Exercise in Middle-Aged Women

Abstract

Listen

Translate article

The acute effects of resistance exercise (RE) on energy expenditure (EE) in the post-exercise period have not been well studied in women. We have previously demonstrated that in untrained women, training volume rather than lean mass exerts the strongest, most consistent effect on EE after an acute bout of RE. However, the effect of training status has not been explored. PURPOSE: To identify factors influencing recovery EE in trained women after an acute bout of RE. METHODS: Ten healthy, middle-aged women (45.6 ± 1.4 years) were recruited after completion of an 8-week resistance training study in which they gained 0.9 ± 0.3 kg of lean mass. Body composition was measured via air displacement plethysmography. Participants completed an acute bout of RE consisting of 3 sets of 8-12 repetitions at 50-80% 1RM for 8 exercises (chest press, leg press, latissimus pulldown, leg extension, shoulder press, leg curl, biceps curl, triceps pushdown). EE (VO2) was measured before and for 120 minutes after RE. Post-exercise EE data were analyzed as 2-minute means at time points 2, 20, 40, 60, 90 and 120 minutes of the recovery period. RESULTS: Participants were overweight (BMI 29.1 ± 1.6 kg/m2), centrally obese (waist circumference 91.5 ± 4 cm), with body composition 41.8 ± 1.8% fat and 58.3 ± 1.8% lean. Mean training time was 19.6 ± 0.7 minutes, training volume was 8,563 ± 643 kg, and total recovery EE was approximately 160 ± 8.5 kcal (32 ± 1.7 L O2). Pearson's correlation analysis found no relationship between recovery EE and age, training volume or delay between cessation of training and commencement of metabolic measurement. Training time, body mass and BMI were positively and significantly related to EE at all recovery time points. Absolute lean mass had the strongest positive relationship to post exercise EE, through 120 minutes of the recovery period (time point 2: r= 0.83, p=0.003; time point 20: r=0.92, p<0.001; time point 40: r=0.85, p=0.002; time point 60: r=0.82, p=0.004; time point 90: r=0.73, p=0.02; time point 120: r=0.85, p=0.002). CONCLUSIONS: In these trained women acute post-exercise EE was influenced primarily by absolute (kg) lean mass. These findings suggest an adaptive mechanism in response to regular training that makes lean mass more metabolically active, so that it positively influences EE without regard for age or training volume.