Observing children's outdoor loose parts play, fundamental movement skills, and physical activity in after-school programs through a behavioral mapping approach.

Background: Outdoor Loose Parts Play (OLPP) has been recognized for its potential to support children's fundamental movement skills (FMS) and physical activity (PA). However, few researchers have explored its association in after-school settings or observed how different outdoor spaces may influence these outcomes. Purpose: We observed patterns of children's FMS and PA across two after-school programs with varied outdoor spaces in Nova Scotia, Canada, following an OLPP intervention. We also explored how types of loose parts and fixed features were associated with specific FMS and PA intensities. Methods: Using a multi-site case study approach, behavioral mapping was conducted with children aged 4-12 years pre/post a six-week OLPP intervention. Movements (FMS) were recorded using the Movement Observations during Play (MOP) measure, and PA intensities were recorded using the Children's Activity Rating Scale (CARS). Proportions of FMS, PA intensities, and environmental interactions (LP and fixed features) pre-post were explored using descriptive analyses and McNemar's test (p < 0.05). Logistic regression examined how interaction with LP and fixed features was associated with the likelihood of observing different movements and PA intensities. Results: Pre-post patterns differed by site. At Site A (larger, suburban, natural outdoor space, pre-existing OLPP), a higher proportion of stability skills were observed, while PA intensity remained unchanged. At Site B (smaller, urban, manufactured outdoor space, limited prior OLPP), a higher proportion of object control skills and moderate-intensity PA were observed. Across both sites, loose manufactured and loose natural materials were more likely to include object control skills, while fixed natural features were more likely to include stability skills. Conclusion: OLPP was associated with site-specific patterns. Findings suggest that LP types and fixed feature affordances may shape opportunities for different movements and PA intensities. These findings can inform educators and policymakers in designing outdoor play spaces that optimize children's movement opportunities.