The impact of Playworks on students' physical activity during recess: findings from a randomized controlled trial.

OBJECTIVE To evaluate the impact of Playworks on students' physical activity during recess. METHOD Twenty-seven elementary schools from six U.S. cities were grouped into blocks and randomly assigned to implement Playworks (treatment) or not (control) during an entire school year (either 2010-2011 or 2011-2012). Study data were collected at the end of the school year only. Fourth- and 5th-grade students (n=2278) reported on their physical activity during recess, and a subset (n=1537) wore accelerometers during recess. Teachers (n=111) also reported on their students' physical activity during recess. RESULTS A significantly higher percentage of teachers in treatment schools reported that their students engaged in an intense physical activity during recess (p=0.01). Marginally significant differences between treatment and control groups were found for the mean number of accelerometer intensity counts recorded per minute during recess (p=0.10) and the mean percentage of time spent in vigorous physical activity during recess (p=0.07). No significant differences were found for student reports about their physical activity during recess (p=0.92). CONCLUSION Teachers in Playworks schools reported that students were more active during recess, but accelerometer and student survey measures showed either no impacts or marginally significant impacts.