School-Based High-Intensity Interval Training Programs for Promoting Physical Activity and Fitness in Adolescents: A Systematic Review

Purpose: This review aimed to evaluate the utility of high-intensity interval training (HIIT) programs integrated into physical education classes. Method: Searches of electronic databases from January 2008 to March 2020. Inclusion criteria: Applied to adolescents aged 10-19 years; applied in school settings; reported results on physical fitness, physical activity (PA), and motivation; at least for 4 weeks; and randomized controlled trials. Studies with adolescents with physical or intellectual limitations were excluded, as well as other interventions parallel to HIIT. Results: Fourteen studies were included. All works present significant improvements in physical fitness and PA. Improvements in body composition recorded, at most, a moderate effect size. HIIT is presented as a powerful stimulus on cardiorespiratory fitness. Improvements in PA registered, a least, a moderate effect size. Conclusions: HIIT in the school context has great potential in improving physical fitness and PA in adolescents. HIIT efficiency (about 10 min) reflects the wide applicability that these protocols can have in physical education classes and great adaptation to the facilities.