Effects of school-based high-intensity interval training on health-related fitness in adolescents.

Background: High-intensity interval training (HIIT) in school settings has been much less studied in adolescents. The aim of this study was to examine the impact of HIIT on health-related fitness in adolescents.

Methods: The total sample consisted of 60 adolescents (age 16.33 ± 0.62 years) from secondary Grammar school, randomly divided into two groups: the experimental (EG) (30) and the control group (CG) (30). The experimental program (12-weeks; 2 times per week) involved two Tabata sessions during one physical education class lasting 4 min each. Participants were tested for health-related fitness components-cardiorespiratory fitness (The Shuttle Run Test (SRT) and strength, hand grip test, standing long jump (SLJ) and counter movement jump (CMJ).

Results: Both the EG and the CG experienced significant positive changes in SRT (meters) and VO values compared to baseline value ( < 0.05), however, the increase in the EG was significantly higher than that in the CG (SRT - η = 0.111; VO - η = 0.111, < 0.01). The EG showed significant improvement in SRT (meters) and VO values compared to the CG ( < 0.01). Regarding the hand grip test results, a significant time × group interaction was found only for right hand ( < 0.01). Moreover, the improvements in SLJ and CMJ values was greater in EG than that in the CG group (SLJ- η = 0.182; CMJ- η = 0.112, < 0.01).

Conclusion: Findings indicate that HIIT implemented into physical education classes can result in significant improvements in selected health related fitness components in adolescents.