# Was it a HIIT? A process evaluation of a school-based high-intensity interval training intervention

PMID: 38684991
Journal: The international journal of behavioral nutrition and physical activity
Published: 2024 Apr 29
Authors: Duncombe SL, Barker AR, Price L, Walker JL, Koep JL, Woodforde J, Stylianou M

## Question

How well was the Making a HIIT school intervention implemented, including reach, dose, fidelity, responsiveness, quality, differentiation, and adaptation?

## Summary

This process evaluation of an 8-week school HIIT program found moderate delivery and attendance: students attended about six workouts on average, and only about half of monitored workouts averaged above 80% HRmax. Teachers found the workouts simple and adaptable, but time, space, uniform, weather, and class management shaped implementation.

## Population

- Year 7/8 students from three Greater Brisbane schools.
- Sample size: 308
- Age: 13.0 +/- 0.6 years
- Sex: 148 girls overall
- Fitness level: General school population
- Health status: Students with medical/injury contraindications excluded

## Methodology

- Mixed-methods process evaluation of a quasi-experimental school intervention
- 8 weeks
- Three Greater Brisbane schools
- Controlled study design.

## Protocol

- Making a HIIT.
- Modality: Teacher-led school HIIT.
- Sets or repetitions: Workout details varied by class and supplementary examples.
- Intensity: Target/fidelity assessed as >=80% HRmax; average 79 +/- 8% HRmax.
- Session duration: 10 minutes; occasionally 5 minutes.
- Frequency: At the beginning of HPE lessons.
- Program length: 8 weeks.
- Progression: Co-designed/adapted workouts rather than fixed progression.
- Usual HPE.
- Modality: Regular health and physical education lessons.
- Intensity: Control lessons spent median 28% of lesson time at >=80% HRmax when monitored.
- Session duration: Standard HPE lesson duration not specified in extraction.
- Frequency: Usual school HPE.
- Program length: 8 weeks.
- Progression: Usual curriculum.

## Outcomes

### Dosage
Status: mixed
Average attendance was moderate and full attendance was uncommon.

10 +/- 3 workouts delivered; 6 +/- 2 attended; 26 students (12%) attended all.

### Fidelity
Status: mixed
Workouts often reached vigorous intensity, but only about half of students averaged above 80% HRmax.

Average HR 79 +/- 8% HRmax; median 55% time >=80% HRmax; 51% students average HR >80% HRmax.

### Enjoyment
Status: mixed
Enjoyment was neutral on average, with low negative affect.

Enjoyment 3.3 +/- 1.1 on 5-point scale; negative affect median 1.5.

## Practical Insights

- Use low-setup, adaptable workouts for school/youth HIIT.
- Measure actual intensity when fidelity matters; delivered HIIT may not be intense for every student.

## Limitations

- Process evaluation, not effectiveness trial.
- Only three schools.
- No student qualitative interviews.
- Researcher involvement could bias interviews.

## Safety And Adherence

- No adverse events were reported in the reviewed text.
- Students with medical conditions or injuries preventing HIIT were excluded, and teachers modified workouts for complexity, space, weather, uniform, equipment setup, and classroom management.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/38684991/) (pubmed)
- [DOI](https://doi.org/10.1186/s12966-024-01599-2) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11059682/) (full text)

## Agent Guidance

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