# Greater effects of high- compared with moderate-intensity interval training on cardio-metabolic variables, blood leptin concentration and ratings of perceived exertion in obese adolescent females PMID: 27274107 Journal: Biology of sport Published: 2016-06-01 Authors: Racil G, Coquart JB, Elmontassar W, Haddad M, Goebel R, Chaouachi A, Amri M, Chamari K ## Question Do high-intensity versus moderate-intensity interval training programs have different effects on cardiometabolic health, body composition, blood leptin, and perceived exertion after maximal testing in obese adolescent females? ## Summary This randomized 12-week school-region study compared high-intensity interval running, moderate-intensity interval running, and no training in obese adolescent females. Both interval programs used repeated 15-second efforts with 15-second active recovery, three days per week, and progressed from 3 x 4-minute blocks to 3 x 8-minute blocks. HIIT used 100% maximal aerobic speed during work intervals, while MIIT used 80% maximal aerobic speed; both recovered at 50% MAS. Both exercise groups improved body composition, VO2max, blood pressure, glucose-insulin markers, leptin, and RPE after maximal exercise. HIIT produced larger percentage changes in several body composition and insulin-related measures and a larger reduction in RPE after maximal testing. Attendance was complete and no training- or test-related injuries were reported. ## Population - Healthy obese female adolescents recruited from three schools. - Sample size: 47 - Age: 14.2 +/- 1.2 years. - Sex: Female adolescents only. - Fitness level: No systematic exercise training during enrollment or previous six months except one hour of school physical education. - Health status: Obese; BMI greater than 97th percentile and body fat greater than 34%; no chronic diseases reported. ## Methodology - Randomized controlled intervention with HIIT, MIIT, and non-exercising control groups. - 12 weeks. - Outdoor athletics track with school-region adolescent participants. - Randomized and controlled study design. ## Protocol - HIIT. - Modality: Outdoor track running. - Work intervals: 15 seconds at 100% MAS. - Recovery: 15 seconds at 50% MAS within blocks; 3 minutes passive recovery between blocks. - Sets or repetitions: Three interval blocks per session, progressing from 3 x 4 minutes to 3 x 6 minutes to 3 x 8 minutes. - Intensity: 100% maximal aerobic speed during work intervals. - Session duration: Approximately 46-58 minutes depending on training phase, including warm-up, interval blocks, between-block recoveries, and cool-down. - Frequency: 3 sessions per week. - Program length: 12 weeks. - Progression: Weeks 1-4: 3 x 4 minutes; weeks 5-8: 3 x 6 minutes; weeks 9-12: 3 x 8 minutes. - MIIT and no-training control. - Modality: MIIT used outdoor track running; control was non-exercising. - Work intervals: MIIT: 15 seconds at 80% MAS. - Recovery: MIIT: 15 seconds at 50% MAS within blocks; 3 minutes passive recovery between blocks. - Sets or repetitions: MIIT used the same three-block progression as HIIT; control had no exercise sessions. - Intensity: MIIT work intervals at 80% MAS; control no training. - Session duration: MIIT approximately matched HIIT session duration by phase; control none. - Frequency: MIIT 3 sessions per week; control none. - Program length: 12 weeks. - Progression: MIIT block duration progressed from 4 to 6 to 8 minutes across three 4-week phases; control no progression. ## Outcomes ### Body composition Status: improved Body mass, BMI Z-score, and body fat decreased in both training groups; waist circumference decreased significantly only in HIIT. HIIT showed greater percentage changes than MIIT and control for body mass, body fat, and waist circumference. Waist circumference within HIIT p=0.017; percentage-change between-group table reports p<0.05 markers for HIIT versus MIIT and control for body mass, body fat, and waist circumference. ### VO2max Status: improved Absolute VO2max increased in both HIIT and MIIT. HIIT +2.22 +/- 2.99%, p=0.019, ES=0.48; MIIT +3.57 +/- 1.39%, p=0.010, ES=0.57; both differed from control in between-group comparison. ### Blood pressure and rate-pressure product Status: improved Resting heart rate, systolic blood pressure, diastolic blood pressure, and rate-pressure product decreased significantly in both training groups. RPP p=0.013, ES=0.53 for HIIT and p=0.036, ES=0.46 for MIIT; table marks HRrest, SBP, DBP, and RPP as significantly different from pre-test. ### Glucose-insulin markers Status: improved Blood glucose, insulin, and HOMA-IR decreased in both training groups; HIIT showed greater percentage changes than MIIT for insulin and HOMA-IR. Table marks within-group changes at p<0.05; percentage changes: insulin HIIT -25.68 +/- 4.24% versus MIIT -19.40 +/- 6.23%, HOMA-IR HIIT -28.74 +/- 4.69% versus MIIT -22.58 +/- 6.72%, with HIIT significantly different from MIIT and control. ### Blood leptin Status: improved Blood leptin decreased significantly in both training groups, with no HIIT-versus-MIIT superiority indicated in percentage change. HIIT -22.31 +/- 6.58%, p=0.021, ES=0.67; MIIT -23.20 +/- 10.18%, p=0.012, ES=0.72; both differed from control. ### RPE after maximal exercise test Status: improved RPE measured 30 minutes after graded exercise testing decreased in both training groups, with larger percentage reduction after HIIT. HIIT -28.97 +/- 6.18%, p=0.001, ES=0.76; MIIT -14.38 +/- 8.70%, p=0.017, ES=0.57; HIIT significantly different from MIIT and control in percentage change. ### Attendance and injury Status: improved Both training groups attended all sessions, and no participant complained or reported training- or test-related injury. ## Practical Insights - Short 15-second work/15-second recovery intervals can be scaled across weeks by increasing total block duration. - For obese adolescent females, both high- and moderate-intensity interval formats improved cardiometabolic outcomes under structured track-based conditions. - HIIT may add extra benefit for body composition, insulin-related measures, and perceived exertion after maximal testing compared with the same interval structure at moderate intensity. ## Limitations - Population limited to obese adolescent females. - No long-term follow-up after the 12-week program. - Training supervision and exact session fidelity monitoring are not fully described. - Protocol depends on MAS testing and outdoor track running. - The study does not directly test home, app-led, or bodyweight HIIT. ## Safety And Adherence - Participants in HIIT and MIIT attended all training sessions. - No participant complained or reported any training- or test-related injury. - Participants with chronic diseases and obesity drug or therapy use were excluded. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/27274107/) (pubmed) - [DOI](https://doi.org/10.5604/20831862.1198633) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885625/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.