| Summary |
The prevalence of childhood overweight has increased for decades, resulting in many children who need physical activity programs that will benefit health. Few physical activity programs for overweight children are available. Additionally, little research exists on circuit training with overweight children. The purpose of this study was to examine the effects of an 8-week circuit training (aerobic and strength training) intervention on physical activity and selected fitness and psychological variables in overweight, prepubescent girls. Overweight, prepubescent girls were assigned to a circuit training group (n = 8) or a control group (n = 6). The training group participated in an 8- week circuit training program that was held two days per week for 60 minutes. Each circuit consisted of 10 alternating aerobic and strength training stations. The control group maintained their normal activity levels. Dependent variables were assessed before and after training. Two-way repeated measures analyses of variance and effect size (ES) estimates using Cohen's delta were calculated to analyze the data. A statistically significant group by time interaction (p = .02) was found for 7-day pedometer data (steps/minute). The circuit training group had a moderate increase in physical activity (ES = 0.45), whereas the control group had a large decrease in physical activity (ES = -1.56) from pre-training to post-training. Moderate to large improvements in muscular strength (1-repetition maximum) were evident for both groups. This increase was probably due to maturation. Although the group by time interaction for the modified pull-up was not statistically significant (p = .08), scores moderately increased for the training group (ES = .44), and showed a small decrease in the control group (ES = -0.30). Sum of skinfolds and percent fat from bioelectrical impedance significantly decreased for both the training and control groups. Importantly, similar improvement in body composition did not occur for body mass index (BMI), indicating that BMI may not be sensitive enough to detect fat loss in overweight, prepubescent girls. A significant group by time interaction (p = .03) was found for maximal treadmill time. The training group showed a large improvement (ES = 1.00), while the control group demonstrated a slight decrement (ES = -0.12). Although the group by time interaction was not statistically significant (p - .08), the body image discrepancy score improved for the training group (ES = -0.31) and became worse for the control group (ES= 0.73). Physical self-efficacy improved by about the same amount in the training group (ES = 0.24) as in the control group (ES = 0.31). The finding of increased levels of physical activity following a circuit training program for overweight, prepubescent girls suggests this type of program may provide long term benefits. Although this circuit training program did not improve body composition more than the control group, it is important to measure percent fat with skinfolds or bioelectrical impedance to assess fat loss in overweight, prepubescent girls. BMI did not reflect the changes in percent fat that occurred in this study. Circuit training was shown to improve aerobic capacity, muscular endurance, level of physical activity, and body image in overweight, prepubescent girls and may provide practitioners with an effective means to address pediatric obesity. |
