en بهداشت Health پژوهشي Original Article <div style="text-align: justify;"><strong>Background and Purpose</strong>: The increasing rates of adolescent overweight and obesity are adversely impacting their physical performance. Also, high-intensity interval training (HIIT) and high-intensity functional training (HIFT) are popular methods to improve functional capacity and weight management. Therefore, this study aimed to assess the effects of six weeks of HIFT versus HIIT protocols on anthropometric measures and functional capacity of overweight and obese adolescent boys.<br> <strong>Materials and Methods</strong>: In this randomized controlled trial, 30 adolescent boys aged 13-15 years, classified as overweight or obese (body mass index (BMI) >25 kg/m2), were randomly and equally assigned to three groups: Control, HIIT, and HIFT. Physical fitness indices (agility and VO2max), functional movement screen (FMS), and anthropometric measures (weight, BMI, and waist-to-hip ratio (WHR)), were assessed. The experimental groups followed either the HIIT or HIFT protocols for six weeks. To analyze the data, a&nbsp;2&nbsp;(time) x3 (group) mixed-model of repeated measures ANOVA was used.<br> <strong>Results</strong>: The demographic characteristics of study population included age =13.93&plusmn;0.82 (years), weight=88.86&plusmn;13.07 (kg), and BMI=29.6&plusmn;2.36 (kg/m2). Data showed that there were no significant differences between groups for age (P=0.256), height (P=0.218), weight (P=0.308), and BMI (P=0.592) at baseline. The results indicated that both HIIT and HIFT protocols had a significant effect on physical fitness indices, FMS, and BMI (all, P&le;0.05). However, the HIFT protocol demonstrated a greater effect compared to HIIT and was significant in all variables (except agility) compared to the control group (P&le;0.05). Despite the lack of a significant difference in post-test weight, the HIFT protocol showed a significant difference compared to the control group (P&le;0.05).<br> <strong>Conclusion</strong>: Six weeks of HIIT and HIFT protocols improved the functional capacity and BMI of overweight and obese adolescents. However, it appears that the HIFT protocol has a greater effect on the functional capacity, possibly due to the improved muscle strength, endurance, and weight loss.</div> Training regime, Obesity, Weight management 267 274 http://jhs.mazums.ac.ir/browse.php?a_code=A-10-1134-1&slc_lang=en&sid=1 Mahmoud Darvishi m.darvishi6428@gmail.com 100319475328460014267 100319475328460014267 No Department of Sports Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran. Vahid Valipour Dehnou valipour.v@lu.ac.ir 100319475328460014268 100319475328460014268 Yes Department of Sports Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran. Rasoul Eslami vahidvalipourdehnou@gmail.com 100319475328460014269 100319475328460014269 No Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Allame Tabataba’i University, Tehran, Iran. Sirous Nazari Pirdoustia vahidvalipourdehno@gmail.com 100319475328460014270 100319475328460014270 No Department of Sports Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran. Hossein Nabavinik nabavinik.h@lu.ac.ir 100319475328460014271 100319475328460014271 No Department of Sports Sciences, Faculty of Literature and Human Sciences, Lorestan University, Khorramabad, Iran.