An eight week school-based intervention with circuit training improves physical fitness and reduces body fat in male adolescents.

School-based intervention programs have been found to effectively improve various fitness and health parameters. However, only few studies so far examined the effect of circuit training in school environment during physical education (PE) classes. The aim of the current study was to examine the effects of an eight-week circuit training on physical fitness and body fat in male adolescents.Thirty nine, 16-year old male high-school students participated in the current study. The students were randomly assigned to intervention and control groups. The intervention period lasted eight weeks and consisted of two circuit training sessions per week performed during regular PE classes. Total body fat was calculated by using bioelectrical impedance analysis. Physical fitness parameters such as cardiorespiratory fitness, flexibility, jumping ability and isometric arm strength were assessed through a battery of field tests. Finally, resting heart rate and blood pressure levels were assessed with an automatic monitor.By the end of the intervention period, total body fat and resting systolic blood pressure were significantly lower while cardiorespiratory fitness was significantly improved in the circuit training group only (P<0.05). In the control group Body Mass Index and total body fat percentage were significantly increased when compared pre- and post-intervention period (P<0.05).Eight weeks of circuit training during PE classes appeared to be effective in improving various physical fitness parameters and reducing fatness in male adolescents.