Increasing use of parks for physical activity has been proposed for improving population health, including mental health. Interventions that aim to increase park use and park-based physical activity include place-based interventions (e.g., park renovations) and person-based interventions (e.g., park-based walking or exercise classes). Using adapted methods from the Community Guide, a systematic review (search period through September 2019) was conducted to evaluate the effectiveness of park-based interventions among adults. The primary outcomes of interest were health-related, including physical and mental health and moderate-to-vigorous physical activity. Twenty-seven studies that met review criteria were analyzed in 2019 and 2020. Seven person-based studies included generally small samples of specific populations and interventions involved mostly exercise programming in parks; all but one had an average quality rating as "high" and all had at least one statistically significant outcome. Of the 20 place-based interventions, 7 involved only 1 or 2 parks; however, 7 involved from 9 to 78 parks. Types of interventions were predominantly park renovations; only 5 involved park-based exercise programming. Most of the renovations were associated with increased park-level use and physical activity, however among those implementing programming, park-level effects were more modest. Less than half of the place-based intervention studies had an average quality rating of "high." The study of parks as sites for physical activity interventions is nascent. Hybrid methods that combine placed-based evaluations and cohort studies could inform how to best optimize policy, programming, design and management to promote health and well-being.

Conflicts of Interest. None.

• R01 CA218188/CA/NCI NIH HHS/United States