Preschool Physical Activity Policy and Children's Physical Activity: A Pragmatic Cluster Randomized Clinical Trial

Importance: Evidence regarding the effectiveness of physical activity (PA) policies within preschool settings remains limited.

Objective

To evaluate the effectiveness of a cocreated preschool-level PA policy on children's accelerometer-measured PA during preschool hours. Design, setting, and participants: This single-blind, parallel-group, cluster randomized clinical trial was performed at public preschools in Stockholm, Sweden. Of 156 randomly sampled preschools invited, 124 were randomized. Children aged 3 to 5 years with parental consent were recruited from September 14 to December 11, 2020, baseline measurements from September 23, 2020, to January 22, 2021, and 6-month follow-up from March 8 to June 11, 2021. Statistical analyses were performed from March 6, 2023, to October 25, 2024.