Effects of Self-efficacy, Planning, and Self-efficacy+Planning Interventions on Body Fat Among Adolescents
Condition: Adolescent Behavior
Study type: Interventional

Summary: 
      This longitudinal experimental study tested the effects of three brief interventions: (1)
      prompting the formation of plans (or implementation intentions), (2) prompting self-efficacy
      beliefs, and (3) prompting planning + self-efficacy in adolescents aged 14-18 years relative
      to an active 'education only' control group.

      It was hypothesized that participants assigned to the interventions would exhibit a smaller
      increase in body fat at 14-month follow-up compared to controls. The study also investigated
      whether the combined planning + self-efficacy intervention would have larger effects on the
      main outcome (body fat) than single-component interventions. Second, it was hypothesized that
      the effects of the intervention conditions on body fat at 14-month follow-up would be
      mediated by their respective psychological and behavioral constructs: self-efficacy and
      planning at T2 (Mediator 1), and by moderate-to-vigorous physical activity (MVPA) at T3
      (Mediator 2). It was expected that the effects of the interventions including the planning
      component (i.e., planning intervention and self-efficacy + planning intervention) would be
      mediated by respective cognitions, i.e. planning, whereas the effects of the interventions
      including self-efficacy component (i.e., self-efficacy intervention and self-efficacy +
      planning intervention) would be mediated by self-efficacy. Finally, it was explored whether
      the effects of the intervention (both direct and indirect effects, via their respective
      psychological variables and MVPA) on body fat would be moderated by the presence of built PA
      facilities, located in the proximity of schools.
    

Detailed description: 
      The experimental procedures were integrated into a health promotion and education program.

      Pre-manipulation education: Across the study groups, participants received a common healthy
      lifestyle education program, focusing on nutrition and physical activity, which was a part of
      the school curriculum. The combination of nutrition and PA interventions is in line with best
      practice guidelines for interventions promoting healthy body weight. The education program
      was delivered by teachers and a group format was used. The groups discussed food composition,
      safe food handling, food labeling, nutrient needs for age and gender groups, dietary
      guidelines, and clinical nutrition issues. The program did not include behavior change
      techniques and was not accompanied by changes in policies.

      The intervention conditions were delivered via a combination of printed forms with
      paper-and-pencil exercises and face-to-face sessions. All experimental conditions included an
      initial session (completing the forms individually in the groups + face-to-face component)
      and sets of handouts for three following weeks. The face-to-face component was delivered
      within three days of completing the initial forms. The initial session was followed by a
      booster session (group + face-to-face components), delivered at 2-month follow-up. Across the
      groups, completing the forms (individual component) took approximately 30 minutes and was
      conducted in classrooms. The face-to-face components took 45-60 minutes and were conducted in
      the offices of school nurses or school psychologists.

      Group intervention component. At the baseline participants completed the intervention
      materials individually, using self-copy paper; the copies were collected for fidelity
      analysis and originals were left for participants. The paper-and-pencil materials followed a
      similar format in four groups in terms of word count, visual format, and the number and
      length of sections requiring participants filling in the blanks.

      Face-to-face intervention component. During the face-to-face component (at the baseline and
      during the booster sessions) all participants received feedback on their body weight,
      information regarding their physical activity levels and energy expenditure based on
      participant's age, gender, body weight, followed by moderate-to-vigorous physical activity
      recommendations (body mass and body fat measured during the booster session was not
      recorded). Next, all participants and experimenters jointly reviewed the forms completed
      during the group component. Adolescents reported included plans and were prompted to provide
      even more detailed responses to questions included in the forms. Experimenters asked
      participants to read the content of the form loudly; looked for sections which were
      incomplete and encouraged adolescents to complete these sections; prompted participants to
      provide detailed responses.
    

Intervention name(s): Self-Efficacy; Planning; Education
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): The introductory part included an abbreviated version of the education materials used in the control group. The self-efficacy materials and forms had four sections: (a) definitions of self-efficacy beliefs, (b) information on the importance of self-efficacy for goal pursuit, (c) recollecting a mastery experience, (d) persuasive statements evoking self-persuasive statements about self-efficacy beliefs. The materials ended with instructions for the following 7 days to recollect self-efficacy enhancing statements every morning. The procedures are based on a self-efficacy intervention by Luszczynska, Tryburcy et al. (2007).
Group and individual components were included. Setting: secondary and high schools.; The introductory part included an abbreviated version of the education materials used in the control group. The planning materials and forms had four sections: (a) information on the importance of planning, including examples of how planning works and what it affects, (b) instructions of what should be included in a good plan (the when, where, and how components), (c) formulating action and coping plans. The materials ended with instructions for the following 7 days to recollect/redo plans every morning.The procedures are based on a planning intervention by Luszczynska, Sobczyk, et al. (2007).
Group and individual components were included. Setting: secondary and high schools.; Participants received a set of educational materials about types of physical activity (PA), PA intensity, exercise calorie expenditure, myths about PA, strength and endurance training, stretching, and general healthy nutrition guidelines. The materials excluded planning and self-efficacy statements.
The materials ended with instructions for the following 7 days to recollect forms of MVPA every morning.
Group and individual components were included. Setting: secondary and high schools.
Other intervention name(s): Physical Activity Self-Efficacy Enhancement; Physical Activity Planning Enhancement; Physical Activity Education
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: adolescence; body fat; physical activity; psychosocial intervention; self-efficacy; planning