Reconstructing Schoolyards With Greenery to Increase Schoolchildren's Physical Activity and Mitigate Climate Changes

Background More than half of Swedish schoolchildren do not meet the physical activity guidelines, which will have long-lasting effects on their health in adulthood. The school environment plays a crucial role in establishing healthy physical activity behaviors for a population.

A formal decision has been made to reconstruct 15 Stockholm public schoolyards from 2024 to 2026. This project is evaluating the effects of this decision.

Project design The project is designed as a quasi-experimental stepped-wedge trial, with schools serving as both intervention and control schools. Over the course of 3 years (2023-2026), a total of 15 schoolyard reconstructions will be evaluated, with 5 reconstructions per year. The units of observation will be second and fifth grade children, totaling 2,700 children.

Methods for data collection The following primary and secondary outcomes will be measured at baseline (May) and at follow-up one year later (May the following year), in all schools, among participating children.

Research questions

• How does schoolyard reconstruction affect physical activity levels, blood pressure, BMI, mental health, sleep, and sick leave in schoolchildren?
• Which components of schoolyard reconstruction are associated with changes (if any) in physical activity levels, blood pressure, BMI, mental health, sleep, and sick leave in schoolchildren?
• What would be the cost-effectiveness of schoolyard reconstruction on the health outcomes, physical activity levels, blood pressure, BMI, mental health, sleep, and sick leave of school children, as well as its impact on the microclimate and CO2-emissions in urban areas, if the project would be extended to other schools in Stockholm, and possibly Sweden as a whole?

Intervention description and theory The schoolyard reconstruction process will use a participatory bottom-up co-creation development approach involving students, school personnel and researchers and will be evidence-based, using prior knowledge on schoolyard features that are associated with children's physical activity during school-hours. Additionally, the schoolyard reconstruction intervention process will be discussed and acknowledged among all co-creators to increase the engagement, buy-in, feasibility, relevance and sustainability of the schoolyard reconstruction intervention.

Workshops will be held by experts from the City of Stockholm, Karolinska institutet and landscape architects with greenery experience, students, school personnel (e.g., principal, teachers etc.), at each school before schoolyard reconstruction initiation. The workshops will process the design and dimension of what components the schoolyard reconstruction should encompass, reflecting school personnel/students' proposals and local challenges and needs.

Statistical analyses Each school undertaking schoolyard renewal will be treated as an independent unit and analyzed separately (i.e., analyses of five separate schoolyard renewals, with appurtenant intervention school, per year). We will match each intervention school, based on school size and socioeconomic factors, with a control school undertaking schoolyard renewal at a different time-point. We deem it appropriate to analyze each control-intervention pair separately as each intervention school represent a unique schoolyard renewal intervention package (different reconstructions). We will also pool the pair-specific estimates, as appropriate, to quantify a global estimate of the total effect of the project.

Societal relevance Most schoolyards in Stockholm lack appealing play areas and are instead dominated by concrete and asphalt surfaces. As school participation is not segregated by socioeconomic factors, schoolyard reconstructions that promote physical activity can benefit children from all socioeconomic groups. Additionally, reconstructing schoolyards with greenery can mitigate health and environmental risks associated with increasing climate changes in urban areas.

Inclusion criteria

On school level:

-School selected for schoolyard reconstruction by the City of Stockholm

On individual level (schoolchildren):

• Enrolled in participating school
• 8-13 years old at the time of study start
• In 2nd or 5th grade
• Parents signed informed consent

Exclusion criteria

On school level:

-School not selected for schoolyard reconstruction by the City of Stockholm

On individual level (schoolchildren):

• Not enrolled in participating school
• Outside 8-13 years old age range and/or not in 2nd or 5th grade
• Parents declined informed consent