How can physical enrichment of school playgrounds improve movement behaviours and developmental outcomes in children and adolescents? A systematic review with meta-analysis.

OBJECTIVE: This study reviewed (1) the effects of physical enrichment of (pre-)school playgrounds on children's and adolescents' movement behaviours and their cognitive, psychological, and social development, and (2) how enrichment characteristics influenced these outcomes. METHODS: A systematic review with meta-analysis was conducted following the PRISMA guidelines. We searched 7 databases (SPORTDiscus, CINAHL, MEDLINE, APA PsycINFO, Cochrane Library, Web of Science, and Scopus) and two reviewers independently screened studies for eligibility. Effect sizes of interventions were calculated using standardized mean differences (Hedges' g) and tested using random-effects models. Meta-regression was used to explore heterogeneous findings. Narrative syntheses were conducted when meta-analysis was not possible. RESULTS: Twenty-eight studies and 19,753 participants were included. Three studies had low risk of bias, 11 studies had high risk of bias, while 14 studies had some concerns. The meta-analyses for movement behaviours showed significant increases in vigorous physical activity (VPA, n = 7 studies, g = 0.17, 95% Confidence Interval (CI): 0.06, 0.27), moderate-to-vigorous physical activity (MVPA, n = 17, g = 0.17, CI: 0.03, 0.30), and steps per minute (n = 3, g = 0.81, CI: 0.03, 1.59) for enrichment interventions relative to control conditions. The results for MVPA had large heterogeneity and were only significant short-term. Line markings alone or in combination with physical structures (e.g., climbing walls) increased MVPA, while involving end-users decreased MVPA. Line markings alone or in combination with physical structures or equipment increased VPA. There was no effect of enrichment for sedentary behaviour, low or moderate intensity physical activity. The results for cognitive (attention restoration and executive functioning), psychological (wellbeing and quality of life), and social (interactions, orientations, and bullying) development were mixed. CONCLUSION: Our findings show that studies on physical enrichment had low methodological quality and findings had high heterogeneity. Line markings in isolation or combined with other enrichment strategies might increase levels of VPA and MVPA in children and adolescents. Evidence on cognitive, psychological and social development is inconclusive due to few and weak studies for these outcomes. We provide future directions for research and practice by drawing from the environmental enrichment paradigm. TRIAL REGISTRATION: PROSPERO registration number CRD42022364392.