Child and youth physical activity throughout the COVID-19 pandemic: The changing role of the neighbourhood built and social environments.

We explored associations between neighbourhood environments and children and youths' moderate-to-vigorous physical activity (MVPA) during three different waves of the COVID-19 pandemic: spring 2020, fall 2020 and spring 2021, using three nationally representative cross-sectional surveys. In wave 2, higher dwelling density was associated with lower odds of a child achieving higher-level MVPA, however, the odds were higher in neighbourhoods with higher density that also had better access to parks. With regard to the social environment, ethnic concentration (wave 3) and greater deprivation (waves 1 and 3) were associated with lower odds of a child achieving higher-level MVPA. Results indicate that built and social environments were differently associated with MVPA levels depending on pandemic restrictions.