MATCHED CALORIC EXPENDITURE OF TWO EXERCISE MODES

Abstract

PURPOSE The study was designed to evaluate the effects of circuit training vs. treadmill exercise on EPOC in untrained women, while accounting for the menstrual cycle. METHODS Eight, untrained females (age = 31.3 ±9.1 years; estimated VO2max = 2.04 ±.26 l min−1; BMI = 24.6 ±3.9 kg ·m2-1) volunteered to participate in the study in which exercise energy expenditure and duration were matched. All testing was performed during the early follicular phase for each subject. Subjects performed two exercise sessions approximately 28 days apart. Resting, supine energy expenditure was measured for 30 minutes preceding exercise and for one hour upon completion of exercise. Metabolic data were collected continuously throughout resting and exercise periods via indirect calorimetry. Circuit training (CT) consisted of three sets of eight common resistance exercises performed at 65% of 1-RM. RESULTS No significant treatment effects were found (< p > 0.05) when comparing pre-exercise resting oxygen uptake and exercise oxygen uptake between conditions. Thus, pre-exercise and exercise conditions were appropriately matched between sessions. Analysis of EPOC data revealed that CT resulted in a significantly higher (< p < 0.05) oxygen uptake during the first 30 minutes of recovery (0.262 ±.01 l ·min−1 vs. 0.222 ±.01 l ·min−1); though, at 60 minutes, treatment differences were not present. Mean VO2 remained significantly higher (0.226 ±.01 l ·min−1 than pre-exercise measures (189 ±.01 l ·min−1) throughout the 60 minute EPOC period (< p < 0.05). Heart rate, RPE and RER were all significantly greater during CT (< p < 0.05). CONCLUSION When exercise caloric expenditure and duration were matched, circuit training was associated with a greater metabolic cost during the early phases of EPOC. A greater sympathetic response coupled with a higher anaerobic demand may have contributed to the larger EPOC following circuit training exercise.