title: Effects of dyadic planning on physical activity in couples: A randomized controlled trial.
abstract: Action planning can help translate physical activity intentions into action by linking situational cues with behavioral responses. Dyadic planning extends action planning and refers to target persons forming plans for their own behavior change together with partners. This study investigated whether a dyadic planning intervention could increase physical activity in target persons and their partners, whether these effects were moderated by relationship quality and mediated by action control, activity-specific received partner support, and control.
  
  
  
  Couples (n = 338; target persons randomized) were randomly assigned to (a) a dyadic planning condition (DPC); (b) an individual planning condition (IPC), in which target persons planned and partners worked on a distractor task; or (c) a control condition (CC), in which couples worked on a distractor task. During 3 assessments up to 6 weeks postintervention, moderate (primary outcome) and vigorous activity were objectively measured; other variables were self-reported. Multilevel and path models were fit.
  
  
  
  There were no beneficial direct effects of the intervention for DPC target persons. Over time, DPC partners' vigorous activity increased, but decreased again. At lower relationship quality, DPC target persons' activity decreased, whereas IPC target persons' vigorous activity increased. Mediation hypotheses were not supported. Mutual influence models indicated positive effects of partners' on target persons' moderate activity in DPC and CC, whereas for IPC, negative effects of target persons' on partners' moderate activity emerged.
  
  
  
  Findings revealed the complexity of effects of dyadic planning on behavior change. Adding relationship quality to the equation clarified effects of DPC and IPC on physical activity. (PsycINFO Database Record
authors.affiliation: Department of Education and Psychology, Freie Universität Berlin.
authors.forename: Nina
authors.initials: N
authors.lastname: Knoll
authors.affiliation: Department of Education and Psychology, Freie Universität Berlin.
authors.forename: Diana Hilda
authors.initials: DH
authors.lastname: Hohl
authors.affiliation: Department of Education and Psychology, Freie Universität Berlin.
authors.forename: Jan
authors.initials: J
authors.lastname: Keller
authors.affiliation: School of Health Sciences, University of Tasmania.
authors.forename: Natalie
authors.initials: N
authors.lastname: Schuez
authors.affiliation: Department of Psychology, SWPS University of Social Sciences and Humanities.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Luszczynska
authors.affiliation: Institute of Medical Psychology, Charité-Universitätsmedizin Berlin.
authors.forename: Silke
authors.initials: S
authors.lastname: Burkert
mesh_terms: D061725:Accelerometry / Q000379:methods / Q000523:psychology*; D000328:Adult; D015444:Exercise / Q000502:physiology / Q000523:psychology*; D005191:Family Characteristics; D005260:Female; D006801:Humans; D033182:Intention; D008297:Male; D008875:Middle Aged; D055815:Young Adult