# Effects of High Intensity Interval Training on Executive Function in Children Aged 8-12 Years

PMID: 31717739
Journal: International journal of environmental research and public health
Published: 2019 Oct 26
Authors: Tottori N, Morita N, Ueta K, Fujita S

## Question

Does a 4-week bodyweight and shuttle-running HIIT program improve physical fitness, working memory, and planning in children aged 8-12 years?

## Summary

This non-randomized controlled study tested a short bodyweight and shuttle-run HIIT program in Japanese children aged 8-12. Over 4 weeks, children assigned by residential area to HIIT improved 20 m shuttle-run performance, sit-ups, and backward digit span working-memory performance compared with no-training controls. Standing long jump, digit span forward, and Tower of Hanoi planning did not show HIIT-specific improvement.

## Population

- Healthy Japanese children in grades 3-6, aged 8-12 years, with no prior HIIT experience.
- Sample size: 56
- Age: 8-12 years.
- Sex: 31 boys and 25 girls completed; HIIT 17 boys/10 girls, control 14 boys/15 girls.
- Fitness level: General schoolchildren; baseline MVPA days measured; HIIT group had lower baseline 20 m shuttle-run performance than controls.
- Health status: No medical, orthopedic, neurological, or attentional disorders limiting exercise or testing.

## Methodology

- Non-randomized controlled pre-post intervention study with a HIIT group and no-training control group.
- 4 weeks, with baseline and post-intervention testing.
- University gymnasium during summer vacation in Japan; testing in gymnasium or indoor hall.
- Controlled study design.

## Protocol

- Children's 30:30 bodyweight HIIT.
- Modality: Bodyweight exercises and short shuttle runs.
- Work intervals: 30 seconds maximal effort.
- Recovery: 30 seconds rest.
- Sets or repetitions: 8-10 minutes of repeated 30:30 intervals.
- Intensity: Target peak HR at least 85% predicted HRmax; mean peak HR 97.0% HRmax.
- Session duration: 23-25 minutes including 10-minute warm-up, 8-10-minute HIIT, and 5-minute cool-down.
- Frequency: 3 sessions/week.
- Program length: 4 weeks.
- Progression: HIIT block increased from 8 minutes to 9 minutes to 10 minutes.
- No-training control.
- Modality: No exercise intervention.
- Program length: 4 weeks.

## Outcomes

### Cardiorespiratory endurance
Status: improved
20 m shuttle-run performance increased only in the HIIT group.

Group x time p=0.043; HIIT within-group p=0.042, d=0.417.

### Muscular endurance
Status: improved
Sit-up performance increased only in the HIIT group.

Group x time p=0.032; HIIT within-group p<0.001, d=0.683.

### Lower-limb power
Status: no clear change
Standing long jump did not show a significant HIIT effect.

Group x time p=0.058; ANCOVA found no between-group difference.

### Working memory
Status: improved
Digit Span Backward score improved in the HIIT group, while controls did not improve.

DSB score group x time p=0.043; HIIT within-group score p=0.003, maximum span p=0.010.

### Planning
Status: no clear change
Tower of Hanoi measures showed time effects but no HIIT-specific group-by-time interactions.

No significant interactions for Tower of Hanoi outcomes.

## Practical Insights

- A short 30:30 bodyweight HIIT block can be feasible in a supervised child gym or school-like setting.
- Working-memory claims should be limited to Digit Span Backward, not broad executive-function improvement.
- Strength/power benefits should not be assumed from light bodyweight HIIT alone.

## Limitations

- Non-randomized allocation by living area.
- Small sample and unequal sex distribution.
- Baseline differences in 20 m shuttle run and standing long jump.
- No socioeconomic-status data.
- No detailed adverse-event or attendance reporting.
- Field fitness tests rather than direct VO2max.

## Safety And Adherence

- Two boys in the HIIT group dropped out due to sickness.
- The article did not report a detailed adverse-event or injury table.
- Children were screened for medical, orthopedic, neurological, and attentional limitations.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/31717739/) (pubmed)
- [DOI](https://doi.org/10.3390/ijerph16214127) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6862681/) (full text)

## Agent Guidance

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