# School-Based Homework Interventions for Improving 24-hour Movement Behaviours in Primary School Children: A Systematic Review and Meta-Analysis

## TL;DR

This study finds that school-based homework interventions can improve children's sleep and reduce sedentary behavior, but not physical activity.

## Contribution

This is the first systematic review and meta-analysis to use device-based measurements of all three 24-hour movement behaviors in homework-based school interventions.

## Key findings

- Homework interventions significantly improved sleep outcomes and reduced sedentary behavior.
- No significant effects on physical activity were found.
- Longer intervention durations were associated with improved physical activity levels.

## Abstract

School-based interventions aimed at improving physical activity (PA), sedentary behaviour (SB) and sleep (i.e., 24-hour movement behaviours) are prevalent. However, the potential use of homework as an intervention method has been largely unexamined. Our objective was to assess the effectiveness of school-based health interventions which implement homework to improve 24-hour movement behaviours in primary school-aged children, whilst examining the moderating effects of study characteristics on intervention effectiveness.

We searched CINAHL, PubMed, Scopus, SPORTDiscus, The Cochrane Library and Web of Science on 4th March 2024 using the following eligibility criteria: (1) participants were aged 5–12 years old; (2) school-based interventions that implemented homework specifically designed to improve one or more 24-hour movement behaviours; (3) randomised- or non-randomised controlled trials, or mixed methods studies where quantitative components included experimental or quasi-experimental data that could be clearly extracted; (4) device-based measured changes in individual or combined 24-hour movement behaviours, or their compositions, were reported. Data were extracted independently by two reviewers with study quality rated using the NIH quality assessment tool. Random-effects meta-analyses were processed to compute standardised mean difference (Hedges’ g), with subgroup analyses, and meta-regressions also conducted.

From 2,281 studies, 19 studies involving 13,160 participants were included for data extraction. Meta-analyses revealed significant favourable association for school-based interventions which implemented homework for sleep outcomes (g = 1.06, p < 0.0001) and SB (g = -0.20, p = 0.0034). No significant effects of the interventions compared to controls were found for PA. Meta-regressions revealed that longer intervention durations significantly improved PA (counts per minute; β = 0.14, p = 0.0241), with no significant effects found for sleep or SB. Subgroup analyses showed significant effects of intervention on SB in RCT’s in both theory-based and non-theory-based studies, though differences between subgroups were not statistically significant. Effects varied between pre- and post-implementations of 24-hour movement guidelines on SB, but these differences were also not statistically significant.

These results highlight a significant gap in school-based interventions implementing homework targeting all 24-hour movement behaviours, emphasising the need for future interventions to focus on reducing SB and improving sleep for more beneficial outcomes.

PROSPERO CRD42024518271.

The online version contains supplementary material available at 10.1186/s40798-025-00898-7.

There is a significant gap in school-based health interventions which implement homework and target all three 24-hour movement behaviours.

To the best of our knowledge, our systematic review and meta-analysis is the first to use device-based measured physical activity, sedentary behaviour and sleep when reviewing school-based health interventions, which implement homework, to improve 24-hour movement behaviours in children.

Even though current school-based interventions primarily focus on physical activity, our research suggest that focus should shift to concentrate more on reducing levels of sedentary behaviour and improving sleep; whilst examining the secondary effects on physical activity. This may lead to more substantial positive results in improving 24-hour movement behaviours, rather than continuing with the emphasis still placed on increasing physical activity.

The online version contains supplementary material available at 10.1186/s40798-025-00898-7.