title: The impact of Playworks on students' physical activity during recess: findings from a randomized controlled trial.
abstract: OBJECTIVE
  To evaluate the impact of Playworks on students' physical activity during recess.
  
  
  METHODS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Mathematica Policy Research, 1100 1st Street, NE, Washington, DC 20002, USA. Electronic address: nbeyler@mathematica-mpr.com.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Beyler
authors.affiliation: Mathematica Policy Research, P.O. Box 2393, Princeton, NJ 08543, USA. Electronic address: mbleeker@mathematica-mpr.com.
authors.forename: Martha
authors.initials: M
authors.lastname: Bleeker
authors.affiliation: Mathematica Policy Research, P.O. Box 2393, Princeton, NJ 08543, USA. Electronic address: sjames-burdumy@mathematica-mpr.com.
authors.forename: Susanne
authors.initials: S
authors.lastname: James-Burdumy
authors.affiliation: Mathematica Policy Research, 505 14th Street, Suite 800, Oakland, CA 94612, USA. Electronic address: jfortson@mathematica-mpr.com.
authors.forename: Jane
authors.initials: J
authors.lastname: Fortson
authors.affiliation: Boston Consulting Group, 53 State Street, Floor 7, Boston, MA 02109, USA. Electronic address: Benjamin.Max@bcg.com.
authors.forename: Max
authors.initials: M
authors.lastname: Benjamin
mesh_terms: D061725:Accelerometry; D002648:Child; D005006:Ethnicity / Q000706:statistics & numerical data; D015444:Exercise; D005178:Faculty; D005260:Female; D006293:Health Promotion / Q000379:methods; D006306:Health Surveys; D006801:Humans; D008297:Male; D009043:Motor Activity; D010988:Play and Playthings; D012044:Regression Analysis; D012146:Rest; D012572:School Health Services / Q000706:statistics & numerical data*; D013334:Students / Q000706:statistics & numerical data*; D014481:United States
keywords: Accelerometry; Child; Elementary schools; Impact study; Physical activity; Playworks