Effects of three distinct protocols of fitness training on body composition, strength and blood lactate

摘要

Circuit training is a very popular methodology in fitness program because it allows to join together cardiovascular and strength training. The purpose of this study was to determine the physiological effects of circuit training performed at different intensities on body composition, strength and blood lactate in middle-aged subjects who had recently undergone only minimum physical training. Forty participants (aged 50-65) were assigned to a control group (CG) or to one of the three exercise treatment groups: Endurance Group (EG), Circuit-Low Intensity Group (CLG), Circuit-High Intensity Group (CHG). The three groups exercised three times per week, 50 min per session for 12 wk using EG (N.=10), CLG (N.=10) or CHG (N.=10). Pre- and post-training, participants performed a submaximal exercise test. Among the three groups, CHG showed the greatest reductions in body weight (BW), percentage of fat mass (FM), waistline, blood lactate (produced at 100 Watt during submaximal test) and greater improvement in 6RM in horizontal leg press and underhand cable pulldowns. The results obtained favored the conclusion that high-intensity exercise combined with endurance training in the circuit training technique is more effective than endurance training alone or low intensity circuit training in improving body composition, blood lactate, moreover CHG results in significantly greater strength increase compared to traditional circuit training.