Effects of Different Types of High-Intensity Interval Training (HIIT) on Endurance and Strength Parameters in Children and Adolescents
Question
Do different HIIT formats in school physical education produce different endurance and strength adaptations in children and adolescents?
Summary
In a school-based randomized trial, 121 students aged 11-15 completed 6 weeks of HIIT in physical education classes. Running 4 x 4, running 12 x 1, and bodyweight circuit HIIT all improved maximal aerobic speed, while the circuit format produced the broadest strength-test improvements.
Methodology
- Healthy students in grades 5-8 who completed the required intervention sessions and endurance testing.
- 121 participants.
- Running.
- Work intervals: 1 minute.
- Recovery: 40 seconds.
- Intensity: About 90% of the running speed that could be maintained for 1 minute; students encouraged to work near 90% HRmax.
- About 20 minutes after a 3-5 minute warm-up.
- 2 physical education sessions per week.
- 6 weeks, 10-12 sessions.
- School-based randomized controlled trial with class-level allocation
- Leger shuttle run converted to maximal aerobic speed, 40-second push-ups, 40-second sit-ups, standing long jump, and 15-second lateral side jumps, and Modified Borg CR exhaustion and motivation ratings were tracked.
Outcomes
Main reported result
Maximal aerobic speed improved significantly in all groups: 4 x 4 running +9.1%, circuit +9.4%, and 12 x 1 running +12.1%.
Main reported result
There was no significant time-by-group interaction for maximal aerobic speed.
Main reported result
The circuit group improved all four strength tests.
Main reported result
The 12 x 1 group improved lateral side jumps and push-ups, while the 4 x 4 group improved sit-ups only.
Main reported result
Average perceived exertion was about Borg CR 5.4, described as hard, with no significant group differences.
Insights
- Short school-friendly HIIT blocks can improve aerobic fitness within 6 weeks.
- Bodyweight circuit HIIT may be better than running-only formats when strength and power outcomes are also desired.
- Varied content and music were identified as useful for motivation in physical education.
Limitations
- Students were randomized by class rather than individually by fitness level.
- Heart rate was not reliably monitored, so achievement of the intended 90% HRmax intensity is uncertain.
- Outcomes used field tests rather than laboratory measures.
- There was no non-HIIT usual-PE control group.
Safety
- All included students completed at least 10 sessions; adverse events were not described in the paper.