title: Correlates of objectively measured physical activity in preadolescent youth.
abstract: OBJECTIVE
  The purpose of this study was to identify the psychosocial and environmental correlates of objectively measured physical activity behavior in a diverse sample of sixth-grade students.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  One hundred ninety-eight sixth-grade students from 4 public middle schools in Columbia, South Carolina. The study group was 52.0% female, 55.1% African-American, with a mean age of 11.4 +/- 0.6 years.
  
  
  METHODS
  Time spent in moderate physical activity (MPA) and vigorous physical activity (VPA) was assessed using a uniaxial accelerometer (CSA WAM 7164) (Computer Science and Applications Inc., Shalimar, FL). Determinant variables included: age, gender, race/ethnicity (demographic); physical activity self-efficacy, social norms related to physical activity, and beliefs regarding physical activity outcomes (psychosocial); and perceived physical activity habits of parents and peers, involvement in community physical activity organizations, involvement in community-based sports programs, access to fitness/sporting equipment at home, and self-reported hours spent watching television or playing video games (environmental).
  
  
  RESULTS
  For boys, physical activity self-efficacy, social norms related to physical activity, and involvement in community physical activity organizations were salient predictors of MPA and VPA. Among girls, only physical activity self-efficacy emerged as a clear predictor of objectively measured physical activity.
  
  
  CONCLUSIONS
  These findings are consistent with previous studies using self-reported physical activity and suggest that interventions to increase physical activity in preadolescent youth should endeavor to boost physical activity self-efficacy by offering a wide selection of enjoyable, developmentally-appropriate physical activity options.
authors.affiliation: Department of Exercise Science, School of Public Health, University of South Carolina, Columbia 29208-5323, USA. strost@sph.sc.edu
authors.forename: S G
authors.initials: SG
authors.lastname: Trost
authors.forename: R R
authors.initials: RR
authors.lastname: Pate
authors.forename: D S
authors.initials: DS
authors.lastname: Ward
authors.forename: R
authors.initials: R
authors.lastname: Saunders
authors.forename: W
authors.initials: W
authors.lastname: Riner
mesh_terms: D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D010809:Physical Fitness / Q000502:physiology; D012044:Regression Analysis; D012494:Sampling Studies; D012737:Sex Factors; D012959:Socioeconomic Factors; D013022:South Carolina; D011795:Surveys and Questionnaires