# Preliminary efficacy and feasibility of embedding high intensity interval training into the school day: A pilot randomized controlled trial

PMID: 26844177
Journal: Preventive Medicine Reports
Published: 2015
Authors: Costigan SA, Eather N, Plotnikoff RC, Taaffe DR, Pollock E, Kennedy SG, Lubans DR

## Question

Can brief HIIT sessions be embedded into the school day, and what preliminary effects do aerobic and resistance-aerobic HIIT have on adolescent fitness, body composition, and motivation?

## Summary

In one Australian secondary school, short 8-10 minute HIIT sessions embedded into PE and lunchtime were feasible and enjoyable. The resistance-and-aerobic program showed small cardiorespiratory fitness effects and both HIIT formats improved some body-size measures, but this was a small pilot.

## Population

- Year 9 and 10 students from one coeducational secondary school in Newcastle, Australia
- Sample size: 65
- Age: 15.8 +/- 0.6 years
- Sex: 45 male, 20 female
- Fitness level: School students; not selected for athletic status
- Health status: Students with consent; school selected for no extra physical activity program

## Methodology

- Pilot three-arm randomized controlled trial
- 8 weeks
- Secondary school PE and lunchtime sessions
- Randomized and controlled study design.

## Protocol

- Resistance and aerobic program.
- Modality: Bodyweight resistance and cardio exercises.
- Work intervals: 30 seconds.
- Recovery: 30 seconds.
- Sets or repetitions: 8-10 rounds depending on week/session length.
- Intensity: Designed as HIIT; average HR including warm-up/cooldown was 77.58% HRmax in RAP.
- Session duration: 8 minutes in weeks 1-3, 9 minutes in weeks 4-6, 10 minutes in weeks 7-8.
- Frequency: 3 sessions per week.
- Program length: 8 weeks.
- Progression: Session duration increased and students gained more exercise/workout choice over time.
- Aerobic exercise program and usual-school control.
- Modality: AEP used gross motor cardio exercises; control continued usual PE/lunch.
- Work intervals: 30 seconds for AEP.
- Recovery: 30 seconds for AEP.
- Sets or repetitions: 8-10 rounds for AEP.
- Intensity: Average HR including warm-up/cooldown was 74.04% HRmax in AEP.
- Session duration: 8-10 minutes for AEP.
- Frequency: 3 sessions per week for AEP.
- Program length: 8 weeks.
- Progression: Same session-duration and choice progression as RAP.

## Outcomes

### CRF
Status: mixed
The resistance-aerobic program showed a small favorable cardiorespiratory fitness effect versus control; the aerobic-only program showed trivial effects.

RAP vs control difference 5.2 PACER laps, 95% CI -4.2 to 14.7, d=0.4; estimated VO2max effect favored RAP by about 5.9 mL/kg/min.

### Body size
Status: improved
Both HIIT groups showed moderate favorable effects on BMI and waist circumference.

BMI effects AEP -0.27 kg/m2 and RAP -0.28 kg/m2, both d=-0.53; waist AEP -1.5 cm d=-0.5 and RAP -2.1 cm d=-0.7, p=0.024 for RAP.

### Muscular fitness
Status: no clear change
No meaningful muscular-fitness effects were detected.

Push-up and standing long-jump effects were not meaningful in the pilot results.

### Feasibility
Status: improved
Recruitment, retention, attendance, and enjoyment supported feasibility.

Consent 86%, retention 90.8%, attendance 2.2 of 3 sessions/week, enjoyment 4.2/5 among 31/43 intervention students.

## Practical Insights

- Very short school-day HIIT sessions can be embedded into PE and lunchtime with good retention.
- Choice, music, partner format, certificates, and visible HR feedback were used to support enjoyment.
- Bodyweight resistance plus cardio may be more promising than aerobic-only HIIT for adolescent CRF.

## Limitations

- Pilot trial from one school.
- Small sample with more boys than girls.
- Field fitness tests rather than gold-standard laboratory measures.
- No objective accounting for physical activity outside the intervention.
- No DXA or laboratory strength testing.

## Safety And Adherence

- The NXML sections reviewed did not report adverse events.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/26844177/) (pubmed)
- [DOI](https://doi.org/10.1016/j.pmedr.2015.11.001) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733031/) (full text)

## Agent Guidance

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