The Effects of Eight-Week High-Intensity Intermittent Training on Body Composition, Aerobic and Anaerobic Performance, Lipid Profile and Hematological Indices in Sedentary Healthy Overweight Adolescent: A Comparison of Volume

Background: Research on the effects of high-intensity intermittent training (HIIT) with different volumes on cardiovascular risk factors is limited. Objectives: The current study aimed to determine the effects of eightweek of highintensity intermittent training and to compare the volumes of training programs on body composition, fitness factors, and cardiovascular risk factors in overweight students. Methods: There were thirty overweight boys (13-16years) as the participants of the study who were randomly divided into three groups, including the control group (n = 10), HIIT-1 (n = 10), and MIIT-2 (n = 10). The HIIT-1 group program included 2 × 8 15 sets (100 110% MAV), and the HIIT-2 group training program included 4 × 4 6 sets (100 110% MAV). These training programs continued three times a week for eight weeks. Yo-Yo recovery test, RAST test, and ELISA technique were applied to measure aerobic and anaerobic performance, lipid profile, and hematological indices, respectively. Results: The findings showed that except for anaerobic performance and hematological variables in the HIIT-1 group and hematological variables in the HIIT-2 group, other research variables of the two training groups were significantly different from the pretest (P 0.05). Besides, in betweengroup comparison, the findings revealed that there was a significant difference between VO2max, HDL, and TG as well as anaerobic performance between the HIIT-1 and HIIT-2 groups (P 0.05). Conclusions: The results suggest that HIIT-1 program is suitable to increase aerobic performance and reduce cardiovascular risk factors, while HIIT-2 program may be applied to increase anaerobic performance because the volume of exercises plays a decisive role in possible adaptation resulting from such exercises.