• Journal of Life Science
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• v.20 no.1
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• pp.124-132
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• 2010

Among students of 'K' boarding high school, located in 'B' city, 32 students whose % body fat was 30% or above were divided into three groups - two exercise groups and one control group. They performed Combined Training - a mix of weight training (WT) and step box training (SBT) - for 65 min a day, 3 days a week, for 8 weeks in total. Group A performed WT 70-80%$RM{\times}3$ sets+SBT (RPE 11-13)${\times}1$ set, and group B performed WT 70-80%$RM{\times}1$ set+SBT (RPE 11-13)${\times}3$ sets to yield data on changes of body composition (Soft Lean Mass, SLM), %fat, WHR), HbA1c, and HOMA-IR. Paired t-test was used to process data within each group. Pre- and post experiment differences rates (%diff) were used to perform one-way ANOVA (Duncan test) for group comparisons. The conclusions derived are as follows. Regarding body composition, exercise groups showed an increase in SLM, but there was no such change in the control group. WHR decreased in group A, but increased in the control group. The % body fat decreased in both exercise groups, but increased in the control group. As for the group comparisons, SLM in group A showed a greater increase than in group B and the control group. WHR in groups A and B showed a greater decrease than the control group. The % body fat in groups A and B showed a greater decrease than the control group. The exercise groups showed a significant decrease in HOMA-IR, but the control group showed a significant increase in HOMA-IR. As for the group comparisons, groups A and B showed a greater decrease in HOMA-IR than the control group. The exercise groups showed a significant decrease in HbA1c, however, the control group showed no change in HbA1c. As for the group comparisons, group A showed a greater decrease in HbA1c than the control group. These results confirm that combined training is more effective in improving body composition and metabolic factors when it includes a high proportion of resistance training, rather than aerobic exercise. The results of the study suggest that it is advisable to set a high proportion of WT when deciding the intensity of combined training.