Introduction: The present study aimed to determine the effect of eight weeks of high-intensity interval training, resistance, and combined training on obesity-related hormonal factors in and sports adaptations in prediabetic adolescent boys
Methods: In a quasi-experimental research project, 40 healthy sedentary boys with an age range of 13-15 years (BMI: 28-31 kg/m²; fat percentage: 32-36%) were selected based on fat percentage and aerobic fitness, and they were assigned into four High-Intensity Interval Training (HIIT), Resistance, Combined and Control groups. Each training includes four sessions per week that lasts 45-60 minutes. Each HIIT session consisted of 6-8 repetitions of 30-60 seconds sprints at 80-85% of reserve heart rate (3.5 minutes rest between repetitions). Resistance training included movements of the main muscles of the upper body, trunk, and lower body. Combined training consisted of a combination of resistance training and HIIT. Fasting glucose concentration, HOMA index, and serum insulin of obese and overweight adolescent boys were measured before and after the training protocols. The changes in each studied indices during different stages of measurement were analyzed using 4x2 analysis of variance and Bonferroni post hoc tests via SPSS-22 software at a significance level less than 0.05.
Results: Fasting glucose concentration did not change significantly in any groups. However, it decreased significantly only in the combined training group. The serum insulin level and the HOMA index decreased significantly in all three training groups, and the reduction of these indices in the combined training group was significantly greater than in the other two groups.
Conclusion: Using the combination of HITT with resistance training improves and reduces the level of insulin, glucose, and insulin resistance. This combined training is a suitable method compared to each HITT and resistance training method alone.