NCT02689973

Effects of Self-efficacy, Planning, and Self-efficacy+Planning Interventions on Body Fat Among Adolescents

Synergistic Effects of Implementation Intention and Self-efficacy on Behavior Change and Body Fat: a Randomized Controlled Trial of Interventions Promoting Physical Activity

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 1,217 (actual)
• Sponsor: University of Social Sciences and Humanities, Warsaw · Academic / Other
• Sex: All
• Age: 14 Years – 18 Years
• Healthy volunteers: Accepted

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.

Conditions

• Adolescent Behavior

Interventions

Type	Name	Description
BEHAVIORAL	Self-Efficacy	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.
BEHAVIORAL	Planning	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.
BEHAVIORAL	Education	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.

Timeline

• Start date: 2009-05-01
• Primary completion: 2015-06-01
• Completion: 2015-06-01
• First posted: 2016-02-24
• Last updated: 2018-09-04
• Results posted: 2018-07-30

Locations

1 site across 1 country: Poland