PASSPORT: A Physical Activity School-Specific PORTfolio intervention evaluated via a stepped wedge design to increase children's physical activity

Physical activity is important for children's physical and mental health. Physical activity declines across childhood with the end of primary school a critical period of change. The COVID-19 pandemic has exacerbated these challenges. There is an urgent need to help more children be active, in particular for universal programs that facilitate physical activity for children regardless of socio-economic position. This presents a major challenge as current physical activity interventions do not work and can exacerbate health inequalities. Numerous "successful" pilot studies have been ineffective in larger trials as implementation and external validity were not considered from the outset. As a field we have focused on ensuring fidelity to a core program rather than designing programs that match the context and system in which they are delivered. The current dominance of the cluster randomised controlled trial to evaluate these programs exacerbates these issues as it ignores the school context that is essential for success.

In this project, we will design a new flexible physical activity program in which schools select core and peripheral components to create a school-specific portfolio. This approach focuses on external validity with the flexible "Portfolio" the intervention. We will also design a new evaluation framework based on a stepped-wedge design that accounts for the school context. The project includes systematic reviews of intervention components, modelling design scenarios, stakeholder engagement, intervention design, piloting new methods and ends with a state-of-the-art stepped-wedge evaluation of a completely novel, portfolio intervention. This project is high risk (new intervention approach, modelling of new methods, new evaluation framework) yet has potential to yield sustainable changes in children's physical activity at the population level while also changing how school-based public health interventions are designed and evaluated.