title: Social cognitive correlates of physical activity across 12 months in cohort samples of couples without children, expecting their first child, and expecting their second child.
abstract: OBJECTIVE
  The onset of parenthood has been identified as a critical risk period for physical inactivity, yet limited research has examined the correlates of physical activity (PA) using theoretical models in longitudinal designs with comparison groups of couples without children. The purpose of this study was to predict PA across 12 months among cohorts of couples with and without children using the theory of planned behavior (TPB).
  
  
  METHODS
  Participants were 314 adults (102 not expecting a child, 136 expecting first child, and 76 expecting second child) who completed baseline demographics, measures of the TPB, and 7-day accelerometry, followed by assessments at six and 12 months.
  
  
  RESULTS
  Hierarchical linear modeling showed some TPB relationships were moderated by parental status and gender. Most notable, time-varying covariate analyses showed perceived behavioral control and intention decreased for new mothers compared to women without children across time. PA was predicted by intention for all cohorts, and intention was predicted by affective and instrumental attitudes and perceived behavioral control for husbands and wives, whereas subjective norm predicted intention only in husbands. For wives, the relationship between intention and instrumental attitudes and perception of behavioral control varied by parental status, and was larger for couples without children compared to second-time parents. Overall, there was considerable coordination in slopes and intercepts among couples, yet individual cognitions were better predictors than partner cognitions.
  
  
  CONCLUSIONS
  The findings provide helpful information for targeting PA interventions among young adults, and suggest that interventions for new mothers may require greater effort to raise the absolute values of control when compared to women without children.
authors.affiliation: Behavioural Medicine Laboratory, University of Victoria.
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Rhodes
authors.affiliation: Faculty of Medicine, Dalhousie University.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Blanchard
authors.affiliation: Department of Sociology, University of Victoria.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Benoit
authors.affiliation: BC Cancer Agency.
authors.forename: Ryna
authors.initials: R
authors.lastname: Levy-Milne
authors.affiliation: School of Exercise Science, Physical & Health Education, University of Victoria.
authors.forename: Patti-Jean
authors.initials: PJ
authors.lastname: Naylor
authors.affiliation: Department of Kinesiology, The Pennsylvania State University.
authors.forename: Danielle
authors.initials: D
authors.lastname: Symons Downs
authors.affiliation: School of Kinesiology, University of British Columbia.
authors.forename: Darren E R
authors.initials: DE
authors.lastname: Warburton
mesh_terms: D000328:Adult; D003071:Cognition; D015331:Cohort Studies; D005191:Family Characteristics; D005260:Female; D006801:Humans; D033182:Intention; D008297:Male; D009035:Mothers / Q000523:psychology / Q000706:statistics & numerical data; D009043:Motor Activity; D010290:Parents / Q000523:psychology*; D011582:Psychological Theory; D055815:Young Adult