# Effects of High-Intensity Interval Training with Change of Direction Versus Small-Sided Games on Physical Fitness in School-Aged Children

PMID: 41006990
Journal: Children
Published: 2025-08-26
Authors: Bibić E, Stupar D, Mitrović N, Zoretić D, Trajković N

## Question

Does change-of-direction HIIT improve school-aged boys' physical fitness differently than small-sided games when both are delivered during PE classes?

## Summary

In 12-year-old boys during school physical education, both change-of-direction HIIT and small-sided games improved shuttle-run distance, standing broad jump, agility tests, and handgrip strength over 8 weeks. There were no significant group-by-time differences, meaning neither format clearly outperformed the other. The study was small, boys-only, and short, but it gives practical school-based interval formats.

## Population

- Healthy school-aged boys aged 11-13 years.
- Sample size: 50
- Age: Mean 12.6 +/- 0.6 years.
- Sex: Male children.
- Fitness level: Regular PE participants; organized sport excluded.
- Health status: Healthy.

## Methodology

- School-based randomized controlled trial.
- 8 weeks.
- Indoor school sports hall during regular physical education classes.
- Randomized and controlled study design.

## Protocol

- HIITcod.
- Modality: Change-of-direction running.
- Work intervals: 15 s vigorous run with 3-5 changes of direction.
- Recovery: 15 s passive recovery standing or walking.
- Sets or repetitions: 4 sets of 6 reps progressing to 5 sets of 12 reps.
- Intensity: Above 75% HRmax.
- Session duration: 45 min PE class with about 30 min main training.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.
- Progression: Increased number of repetitions and sets.
- Small-sided games.
- Modality: 2v2 and 3v3 games on scaled indoor courts.
- Work intervals: 4-5 min game bouts.
- Recovery: 2 min passive recovery.
- Sets or repetitions: 4-5 bouts.
- Intensity: Comparable high intensity; average HR 167.0 +/- 6.14 bpm.
- Session duration: 45 min PE class with about 30 min game conditioning.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.
- Progression: Game formats alternated weekly.

## Outcomes

### Between-group effects
Status: no clear change
No significant group-by-time interaction was observed for any outcome.

All interaction p > .05.

### Shuttle run
Status: improved
Both groups improved shuttle-run distance.

HIITcod 535.3 to 657.3 m, p = .001; SSG 518.7 to 604.0 m, p = .02.

### Power and agility
Status: improved
Both groups improved standing broad jump and agility tests.

Standing broad jump p = .020 HIITcod and p = .041 SSG; Illinois and T-test improved in both groups.

### 20-m sprint
Status: no clear change
Neither group improved 20-m sprint performance significantly.

p > .05.

## Practical Insights

- 15/15 change-of-direction intervals are a compact school PE format.
- Game-based intervals may deliver similar fitness benefits with more playful engagement.
- No evidence here that HIITcod outperforms SSG.

## Limitations

- Single school.
- Boys only.
- Small sample and short duration.
- No formal a priori power calculation.
- Fixed test order may introduce fatigue effects.
- No long-term or enjoyment outcomes.

## Safety And Adherence

- No adverse-event details were reported.
- Sessions were supervised by a researcher and PE specialist with HR monitoring.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/41006990/) (pubmed)
- [DOI](https://doi.org/10.3390/children12091124) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12468730/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.