title: Physical activity in adolescents: analysis of the social influence of parents and friends.
abstract: OBJECTIVE
  To analyze the association between physical activity and social support from parents and friends on the physical activity level among adolescents.
  
  
  METHODS
  Data from 2,361 adolescents (56.6% females; mean age 16.4; SD = 1.2), from public and private high schools were analyzed. The physical activity level of the adolescents, parents, and friends were measured through a questionnaire. Parents' and friends' support and self-efficacy were measured using two previously tested scales. Data analysis was performed using the structural equation modeling in IBM® SPSS® Amos™ 20.0.
  
  
  RESULTS
  Physical activity of friends was directly associated with physical activity level of adolescents. Physical activity of the father was associated with that of their sons, and the physical activity of mother was associated with that of their daughters. An indirect association was identified between the physical activity of parents and friends with physical activity level of the adolescents, mediated by social support. Social support was directly associated with physical activity in adolescents of both genders and indirectly mediated by self-efficacy.
  
  
  CONCLUSIONS
  Parents and friends have a social influence on adolescents' level of physical activity through the mechanism of behavior modeling or through social support, mediated by self-efficacy.
authors.affiliation: Post-graduation Program in Physical Education, Universidade Federal da Paraíba, João Pessoa, PB, Brazil; Study and Research Group in Epidemiology of Physical Activity, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Luanna Alexandra
authors.initials: LA
authors.lastname: Cheng
authors.affiliation: Post-graduation Program in Physical Education, Universidade Federal da Paraíba, João Pessoa, PB, Brazil; Study and Research Group in Epidemiology of Physical Activity, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Gerfeson
authors.initials: G
authors.lastname: Mendonça
authors.affiliation: Study and Research Group in Epidemiology of Physical Activity, Universidade de São Paulo, São Paulo, SP, Brazil; Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil; Universidade Federal da Paraíba, João Pessoa, PB, Brazil. Electronic address: jcazuzajr@hotmail.com.
authors.forename: José Cazuza de
authors.initials: JC
authors.lastname: Farias Júnior
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology / Q000523:psychology; D005260:Female; D033062:Friends / Q000523:psychology*; D006801:Humans; D008297:Male; D009043:Motor Activity; D010290:Parents / Q000523:psychology*; D012574:Schools; D020377:Self Efficacy; D012737:Sex Factors; D012944:Social Support; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Adolescentes; Adolescents; Amigos; Apoio social; Atividade motora; Friends; Motor activity; Pais; Parents; Social support