title: Exploring associations between parental and peer variables, personal variables and physical activity among adolescents: a mediation analysis.
abstract: BACKGROUND
  This study aimed to investigate how parental and peer variables are associated with moderate- to-vigorous intensity physical activity (MVPA) on week- and weekend days among Australian adolescents (13-15 y), and whether perceived internal barriers (e.g. lack of time), external barriers (e.g. lack of others to be physically active with) and self-efficacy mediated these associations.
  
  
  METHODS
  Cross-sectional data were drawn from the Health, Eating and Play Study, conducted in Melbourne, Australia. Adolescents (mean age = 14.11 ± 0.59 years, 51% girls) and one of their parents completed a questionnaire and adolescents wore an ActiGraph accelerometer for a week (n = 134). Mediating effects of perceived barriers and self-efficacy were tested using MacKinnon's product-of-coefficients test based on multilevel linear regression analyses.
  
  
  RESULTS
  Parental logistic support was positively related to MVPA on weekdays (τ = 0.035) and weekend days (τ = 0.078), peer interest (τ =0.036) was positively related to MVPA on weekdays, and parental control (τ = -0.056) and parental concern (τ = -0.180) were inversely related to MVPA on weekdays. Internal barriers significantly mediated the association between parental logistic support and MVPA on weekdays (42.9% proportion mediated). Self-efficacy and external barriers did not mediate any association.
  
  
  CONCLUSIONS
  Interventions aiming to increase adolescents' MVPA should involve parents, as parental support may influence MVPA on weekdays by reducing adolescents' perceived internal barriers. Longitudinal and experimental research is needed to confirm these findings and to investigate other personal mediators.
authors.affiliation: Department of Movement and Sport Sciences, Ghent University, Ghent, Belgium. maite.verloigne@ugent.be.
authors.forename: Maïté
authors.initials: M
authors.lastname: Verloigne
authors.forename: Jenny
authors.initials: J
authors.lastname: Veitch
authors.forename: Alison
authors.initials: A
authors.lastname: Carver
authors.forename: Jo
authors.initials: J
authors.lastname: Salmon
authors.forename: Greet
authors.initials: G
authors.lastname: Cardon
authors.forename: Ilse
authors.initials: I
authors.lastname: De Bourdeaudhuij
authors.forename: Anna
authors.initials: A
authors.lastname: Timperio
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D055361:Multilevel Analysis; D017008:Negotiating; D016487:Parenting; D010290:Parents; D010379:Peer Group; D010465:Perception; D020377:Self Efficacy; D011795:Surveys and Questionnaires