Physical Activity and Social Behaviors of Urban Children in Green Playgrounds.

INTRODUCTION: Nature exposure is associated with many wellbeing benefits. However, the influence of green space on the physical activity and social behaviors of children is not completely understood. The purpose of the study was to complete a stepwise impact evaluation of a large-scale playground greening project at a Title 1 elementary school in Los Angeles, California.
METHODS: Physical activity and social interaction data were collected with direct observation and accelerometers pre-, immediately post-, and 4 months post-greening at control (students enrolled=393) and experimental (students enrolled=538) locations from 2016 to 2017. Effects of relevant variables on recess behavior were analyzed with linear mixed models in 2018.
RESULTS: Zone popularity and recess behaviors did not change for control students during the study (p>0.05). Areas replaced by green space became the most popular for experimental students who transitioned from traditional playground games/sports to tag/chasing, gymnastics, climbing/jumping, and creative play. The percentage of students observed as sedentary decreased by 10.0% (95% CI=4.9%, 15.0%) at 4 months, p=0.003. Vigorous activity participation increased pre to post at the individual (48.5%, 95% CI=29.1%, 67.9%, p<0.001) and population level (41.2%, 95% CI=27.3%, 55.1%, p=0.003) and remained higher than pre-greening at 4 months (p<0.05) for girls in the experimental group only. The moderate to vigorous physical activity differential between green space and hardscape was greater for fifth graders than all other grades, p=0.002. Student physical and verbal conflict rates decreased below pre-greening rates after 4 months for the experimental group, p<0.001.
CONCLUSIONS: Results suggest that adding green space to asphalt-covered schoolyards helps expose children to nature, increases daily activity levels, and promotes social wellbeing in sex- and age-dependent ways.