# The great live and move challenge and the promotion of physical activity in children: results from a two-school-year cluster-randomized trial

## TL;DR

A two-year school-based program increased physical activity in children, but the psychological factors behind this effect need further study.

## Contribution

The study shows a long-term intervention based on the theory of planned behavior can boost children's physical activity.

## Key findings

- The intervention group had a significantly higher proportion of children meeting PA guidelines after 16 months.
- The link between intentions and physical activity was stronger in the intervention group.
- TPB variables did not mediate the intervention's impact on physical activity.

## Abstract

Population surveys indicate that a large proportion of children worldwide do not meet the recommended 60 min of moderate-to-vigorous physical activity (PA) daily. This study aimed to assess the impact of the Great Live and Move Challenge (GLMC), a theory of planned behavior (TPB)-based intervention, on PA and TPB variables in French primary school children over two school years. Secondary objectives included assessing whether TPB variables mediated the GLMC’s impact on PA and whether the GLMC impacted the strength of the link between TPB variables.

A cluster-randomized controlled trial was conducted over 16 months. One hundred primary schools were randomized into an intervention or control group. A total of 2723 children aged 7–11 years (mean age: 9.1; 49.7% boys) were included (n intervention = 1420, n control = 1303). The GLMC, based on TPB, comprised a motivational phase (targeting attitudes, subjective norms, and perceived behavioral control) and a volitional phase (notably focusing on the intentions-PA link). The intervention involved teachers, parents, and community stakeholders. The primary outcome was the change in the proportion of children meeting PA guidelines after 16 months. Secondary outcomes included changes in mean daily PA and TPB variables. Assessments occurred at baseline, 4, 12, and 16 months. Data were analyzed using mixed models and path analyses.

The “time × group” interaction indicated that, compared with the control group, the intervention group had a significantly higher proportion of children meeting international PA guidelines after 16 months (OR = 3.38, 95% CI = 2.50 to 4.56, P < 0.001). TPB variables did not significantly mediate the impact of the GLMC on mean daily PA at 16 months. The path coefficient between intentions and mean daily PA was significantly higher in the intervention group than in the control group at 4 (CR = 2.45; β = 0.22 vs. 0.13) and 16 months (CR = 2.87; β = 0.24 vs. 0.14).

The GLMC increased the proportion of children meeting PA guidelines over 16 months, and may help bridge the intentions-PA gap. The absence of mediation by TPB variables highlights the need to investigate other psychosocial mechanisms to better understand how the GLMC promotes PA in children.

International Standard Randomized Controlled Trial Number (ISRCTN) Registry: 61,116,221 (retrospectively registered).

The online version contains supplementary material available at 10.1186/s12966-025-01849-x.