Metabolic indicators and energy expenditure in two models of health club classes: aerobic fitness class vs. strength fitness class

Abstract

This study was designed to analyze the differences in metabolic indicators and energy expenditure (EE) between two models of health club fitness classes: Aerobic Fitness Class (AFC) and Strength Fitness Class (SFC). Fifteen adult women (mean ± standard deviation: age, 29.0 ± 3.3 years; height, 161.8 ± 4.8 cm; body mass index, 21.5 ± 1.6 kg/m2) participated in the present study. Maximum oxygen uptake (VO2max) and maximum heart rate (HRmax) were measured directly during a maximal treadmill test. During AFC and SFC sessions, heart rate (HR), oxygen uptake (VO2), respiratory exchange ratio (RER), metabolic equivalents (MET), percentage of fat oxidation (%FAT), percentage of carbohydrate oxidation (%CHO) and EE were assessed by indirect calorimetry using a portable gas analyzer (K4b2). Student’s paired samples t test was used to analyze differences between AFC and SFC. Significance level was set at 5%. Effect sizes (Cohen’s d) were observed. There were greater values during AFC in comparison with SFC on the following variables: VO2 (1959.3 ± 273.2 vs. 1122.7 ± 187.7 ml kg−1 min−1; p < 0.001; ES = 3.69); HR (161 ± 14 vs. 133 ± 17 bpm; p < 0.001; ES = 1.86); MET (10.0 ± 1.2 vs. 5.8 ± 0.9 MET; p < 0.001; ES = 4.1); total EE (259.6 ± 24.9 vs. 151.7 ± 22.3 kcal; p < 0.001; ES = 4.73); %VO2max (76.9 ± 8.6 vs. 44.3 ± 8.1%; p < 0.001; ES = 4.04); %HRmax (84.2 ± 5.8 vs. 69.7 ± 7.9%; p < 0.001; ES = 2.17) and CHO oxidation rate (139.9 ± 16 vs. 82.4 ± 13.8 kcal h−1; p < 0.001; ES = 3.98). Further, CHO was the main substrate for both classes. These results suggest that AFC induces greater EE than SFC. Moreover, engaging AFC or SFC 3–5 times a week seems enough to achieve international physical activity recommendations per week to promote several health benefits. Finally, carbohydrate is the main energy supply for both types of fitness classes.