title: Social and Psychological Factors Associated With Adolescent Physical Activity.
abstract: The purpose of this study was to examine, using structural equation modeling, the associations between nominated friend physical activity (PA), friend social support with individual PA-related psychological factors, and adolescent PA.
  
  
  
  Data were obtained from EAT 2010 (Eating and Activity Among Teens), a large cross-sectional study conducted in 20 middle and high schools. The sample consisted of 1951 adolescents (mean age: 14.25 ± 1.96, 54% female, 68% ethnic minorities). PA, parent and friend social support (perceived social support for PA from parents and friends), and psychological measures (PA enjoyment, PA self-efficacy, and PA barriers) were assessed by self-report questionnaires. The SEM analysis consisted of 1 observed variable: friend PA, and 2 latent constructs: psychological factors, perceived social support.
  
  
  
  The model was a good fit, indicating that there were significant direct effects of both friend PA (P < .01) and psychological factors (P < .0001) on adolescent PA. In addition, psychological factors mediated the association between friend PA and adolescent PA.
  
  
  
  The results of this model suggest that psychological factors and friend PA are associated with adolescent PA, and that psychological factors may play an important role. Future studies should further examine the association of both friend PA and psychological variables with adolescent PA.
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Garcia
authors.forename: John R
authors.initials: JR
authors.lastname: Sirard
authors.forename: Ross
authors.initials: R
authors.lastname: Larsen
authors.forename: Meg
authors.initials: M
authors.lastname: Bruening
authors.forename: Melanie
authors.initials: M
authors.lastname: Wall
authors.forename: Dianne
authors.initials: D
authors.lastname: Neumark-Sztainer
mesh_terms: D000293:Adolescent; D003430:Cross-Sectional Studies; D005006:Ethnicity; D015444:Exercise / Q000523:psychology*; D005260:Female; D033062:Friends; D006801:Humans; D008297:Male; D010290:Parents; D012044:Regression Analysis; D012574:Schools; D020377:Self Efficacy; D057566:Self Report; D060756:Social Networking; D012944:Social Support; D011795:Surveys and Questionnaires
keywords: friends; self-efficacy; social influences; structural equation modeling