Background Cardiorespiratory fitness (CRF) is an important marker of current and future health status. The primary aim of our study was to evaluate the impact of a time-efficient school-based intervention on older adolescents’ CRF.
Methods Two-arm cluster randomised controlled trial conducted in two cohorts (February 2018 to February 2019 and February 2019 to February 2020) in New South Wales, Australia. Participants (N=670, 44.6% women, 16.0±0.43 years) from 20 secondary schools: 10 schools (337 participants) were randomised to the Burn 2 Learn (B2L) intervention and 10 schools (333 participants) to the control. Teachers in schools allocated to the B2L intervention were provided with training, resources, and support to facilitate the delivery of high-intensity interval training (HIIT) activity breaks during curriculum time. Teachers and students in the control group continued their usual practice. The primary outcome was CRF (20 m multi-stage fitness test). Secondary outcomes were muscular fitness, physical activity, hair cortisol concentrations, mental health and cognitive function. Outcomes were assessed at baseline, 6 months (primary end-point) and 12 months. Effects were estimated using mixed models accounting for clustering.
Results We observed a group-by-time effect for CRF (difference=4.1 laps, 95% CI 1.8 to 6.4) at the primary end-point (6 months), but not at 12 months. At 6 months, group-by-time effects were found for muscular fitness, steps during school hours and cortisol.
Conclusions Implementing HIIT during curricular time improved adolescents’ CRF and several secondary outcomes. Our findings suggest B2L is unlikely to be an effective approach unless teachers embed sessions within the school day.
Trial registration number Australian New Zealand Clinical Trials Registry (ACTRN12618000293268).
- aerobic fitness
- physical activity
- physical fitness
- intervention effectiveness
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Contributors DRL: conceptualisation, methodology, investigation, resources, writing-original draft, supervision, funding acquisition. JJS: methodology, investigation, resources, writing-review and editing, funding acquisition. NE: methodology, investigation, resources, writing-review and editing, funding acquisition. AAL: investigation, resources, data curation, writing-review and editing. PM: methodology, resources, writing-review and editing, funding acquisition. CL: methodology, resources, writing-review and editing, funding acquisition. RP: methodology, writing-review and editing, funding acquisition. MN: methodology, writing-review and editing, funding acquisition. SK: investigation, data curation, writing-review and editing, project administration. EGH: formal analysis, writing- review and editing, funding acquisition. NW: writing- review and editing, formal analysis. MN: resources, writing- review and editing. TTS: software, writing-review and editing. MM: investigation, data curation, software, writing-review and editing. SRV: investigation, data curation, writing-review and editing. PG: investigation, data curation, writing-review and editing. FRW: investigation, data curation, writing-review and editing. SAC: resources, writing-review and editing. CHH: methodology, software, resources, writing-review and editing, funding acquisition.
Funding The study was funded by the National Health and Medical Research Council (APP1120518) and the New South Wales Department of Education School Sport Unit. DRL is supported by a National Health and Medical Research Council Research Fellowship (APP1154507).
Competing interests None declared.
Patient and public involvement statement The need for a time-efficient physical activity intervention for older adolescents was identified through consultation with the New South Wales Department of Education School Sport Unit, who provided initial funding to evaluate feasibility of the B2L intervention. We conducted a pilot study in two secondary schools, and participants (ie, students and teachers) were invited to provide feedback on the intervention. This feedback was then used to refine the B2L intervention components and implementation strategies. Study findings will be disseminated through institutional websites, press releases, and tailored messages to schools, educational organisations, and governing bodies.
Patient consent for publication Not required.
Ethics approval This study received approval from the University of Newcastle (H-2016-0424) and the NSW Department of Education (SERAP: 2017116) human research ethics committees.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. Requests for access to data from the study should be addressed to the corresponding author at firstname.lastname@example.org. The study protocol has been published. All proposals requesting data access will need to specify how it is planned to use the data, and all proposals will need approval of the trial co-investigator team before data release.
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