RESEARCH
The Impact of Schoolyard Greening on Children’s Physical Activity and Socioemotional Health: A Systematic Review of Experimental Studies
Summary
This document presents a systematic review focused on the impact of schoolyard greening on children’s physical activity (PA) and socioemotional health (SEH). Schoolyard greening refers to transforming outdoor school environments with natural elements like trees, flowers, and grass, contrasting with traditional asphalt playgrounds. The review was conducted according to PRISMA guidelines and aimed to synthesize findings from experimental studies, which offer the possibility of inferring causality, unlike many previous cross-sectional studies. Researchers searched four electronic databases and conducted hand-searches. Inclusion criteria specified experimental or quasi-experimental studies involving children under 18, exposed to greened schoolyards pre and post intervention, with a control group or self-controls, and measuring PA and/or SEH outcomes. Out of an initial 1843 articles, only six met these criteria and were included in the review. These studies employed diverse interventions, including traditional greening, adding AstroTurf, and Social and Therapeutic Horticulture, and used a variety of data collection tools such as accelerometers, observational methods, and numerous questionnaires and tests for various SEH constructs. Due to the heterogeneity of study designs, interventions, outcomes, and measurement tools across the included studies, a narrative synthesis was performed.
The narrative synthesis revealed a general consensus indicating a positive impact of schoolyard greening on children’s PA and SEH outcomes. However, the findings for specific measures and subgroups were often mixed. While some studies reported beneficial changes in PA, such as increased utilization of greened areas and positive effects on girls’ PA, others found non-significant changes in overall PA levels. Similarly, for SEH, studies reported positive associations with attention restoration and mental well-being, along with mixed results for prosocial behaviors, including significant reductions in conflicts, but also negative effects in some subgroups. A notable limitation identified by the review is that all six included studies used quasi-experimental designs, meaning schools or participants could not be randomly assigned to intervention or control groups. Furthermore, the heterogeneity of methods makes it difficult to draw strong, generalizable conclusions and highlights the need for more rigorous, well-designed experimental trials in future research. The review suggests that schoolyard greening is a viable intervention that could help reduce health equity gaps.
