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
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.
Study Overview
Status
Conditions
Intervention / Treatment
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.
Study Type
Enrollment (Actual)
Phase
- Not Applicable
Contacts and Locations
Study Locations
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Warsaw, Poland, 03-815
- University of Social Sciences and Humanities
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
Inclusion Criteria:
- Healthy adolescents
- Adolescents with chronic conditions but without contraindications for moderate-to-vigorous physical activity
Exclusion Criteria:
- Adolescents who were younger than 14 years old
- Adolescents who declared plans for changing schools during the following year (e.g., due to graduation or moving to another region)
- No parental consent at the baseline
- Existing diseases with contraindications for moderate-to-vigorous physical activity
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Prevention
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Double
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
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Experimental: Self-efficacy
The self-efficacy intervention protocol included following behavior change techniques (BCT; Michie et al., 2011): barrier identification, prompting focus on past success, and prompting self-talk.
Applications of all BCT included references to self-efficacy beliefs.
The intervention was integrated into health promotion-nutrition education program (8h).
The intervention was applied twice (the baseline and 2-month follow-up).
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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.
Other Names:
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 Names:
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Experimental: Planning
The following BCT were included in the planning intervention protocol: action planning, barrier identification, prompting self-talk, relapse prevention/coping planning. Applications of all BCT included references to planning. The intervention was integrated into health promotion-nutrition education program (8h). The intervention was applied twice (the baseline and 2-month follow-up). |
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 Names:
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.
Other Names:
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Experimental: Combined planning+self-efficacy
This condition included all BCT applied in the planning and self-efficacy arms.
The intervention was integrated into health promotion-nutrition education program.
The intervention was applied twice (the baseline and 2-month follow-up).
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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.
Other Names:
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 Names:
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.
Other Names:
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Active Comparator: Education
The education group received extended physical activity education program.
The physical activity education was integrated into health promotion-nutrition education program.The education program was applied twice (the baseline and 2-month follow-up).
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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 Names:
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Body Fat Tissue
Time Frame: Baseline to 14-month follow-up
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bioimpedance (BIA) method (Kyle et al., 2004), which determines the electrical impedance of an electric current through body tissues.
Fat tissue was estimated with Schaefer equation for BIA which is considered a reliable index of body fat in adolescent from primarily white backgrounds (Cleary et al., 2008).
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Baseline to 14-month follow-up
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Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Moderate-to-vigorous Physical Activity (MVPA)
Time Frame: Baseline to 14-month follow-up
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Items from Godin and Shephard's (1985) Leisure-Time Exercise Questionnaire (e.g., 'Considering a 7-day period [a week], how many times on the average do you do the following kinds of exercise for more than 15 minutes during your free time: strenuous exercise [heart beats rapidly], i.e. running, jogging, hockey, soccer, basketball, cross-country skiing, vigorous swimming, vigorous long distance bicycling'). Number of Items: 2 Response format: open ended, the participant indicated the number of 15 min blocks of physical activity. Scoring: the total (sum) score of 2 items Scoring formula: the sum score for the number of minutes of MVPA per week, i.e. individual score = {response to item #1 x 15} + {response to item # 2 x 15}) The range for the score (i.e. the sum score of 2 items): minimum = 0, maximum = 42 Interpretation: Higher scores indicate better results (more minutes of MVPA per week) |
Baseline to 14-month follow-up
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The Use of Physical Activity Planning (the Use of Planning)
Time Frame: Baseline to 2-month follow-up
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Use of physical activity planning was measured with four items (e.g., 'I have my own plan regarding when to engage in exercise of moderate-to-vigorous intensity'; Schwarzer et al., 2008). Number of Items: 4 Response format: Responses ranged from 1 ('definitely not') to 4 ('exactly true'). Scoring: the total score of 4 items Scoring formula: the sum score for the 4 items divided by 4, i.e. {item #1 + item #2 + item #3 + item #4} : 4 The range for the score (i.e. the sum score of 4 items divided by 4): minimum = 1, maximum = 4 Interpretation: Higher scores indicate better results (the more frequent use of planning) |
Baseline to 2-month follow-up
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Physical Activity Self-efficacy (PA Self-efficacy)
Time Frame: Baseline to 2-month follow-up
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Physical activity self-efficacy (T1 and T2) was measured with 9 items (e.g., 'I am able to maintain regular MVPA even if I would have to reorganize my daily life'; Luszczynska et al., 2011). Number of Items: 9 Response format: Responses ranged from 1 ('definitely not') to 4 ('exactly true'). Scoring: the total score of 9 items divided by 9 Scoring formula: the sum score for the 9 items divided by 9, i.e. {item #1 + item #2 + item #3 + item #4+ item #5 + item #6 + item #7 + item #8 + item #9} : 9 The range for score (i.e. the sum score of 9 items divided by 4): minimum = 1, maximum = 4 Interpretation: Higher scores indicate better results (the higher levels of PA self-efficacy) |
Baseline to 2-month follow-up
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Collaborators and Investigators
Investigators
- Principal Investigator: Aleksandra Luszczynska, PhD, University of Social Sciences and Humanities
Publications and helpful links
General Publications
- Godin G, Shephard RJ. A simple method to assess exercise behavior in the community. Can J Appl Sport Sci. 1985 Sep;10(3):141-6.
- Luszczynska A, Sobczyk A, Abraham C. Planning to lose weight: randomized controlled trial of an implementation intention prompt to enhance weight reduction among overweight and obese women. Health Psychol. 2007 Jul;26(4):507-12. doi: 10.1037/0278-6133.26.4.507.
- Kyle UG, Bosaeus I, De Lorenzo AD, Deurenberg P, Elia M, Gomez JM, Heitmann BL, Kent-Smith L, Melchior JC, Pirlich M, Scharfetter H, Schols AM, Pichard C; Composition of the ESPEN Working Group. Bioelectrical impedance analysis--part I: review of principles and methods. Clin Nutr. 2004 Oct;23(5):1226-43. doi: 10.1016/j.clnu.2004.06.004.
- Michie S, Ashford S, Sniehotta FF, Dombrowski SU, Bishop A, French DP. A refined taxonomy of behaviour change techniques to help people change their physical activity and healthy eating behaviours: the CALO-RE taxonomy. Psychol Health. 2011 Nov;26(11):1479-98. doi: 10.1080/08870446.2010.540664. Epub 2011 Jun 28.
- Luszczynska A, Schwarzer R, Lippke S, Mazurkiewicz M. Self-efficacy as a moderator of the planning-behaviour relationship in interventions designed to promote physical activity. Psychol Health. 2011 Feb;26(2):151-66. doi: 10.1080/08870446.2011.531571.
- Cleary J, Daniells S, Okely AD, Batterham M, Nicholls J. Predictive validity of four bioelectrical impedance equations in determining percent fat mass in overweight and obese children. J Am Diet Assoc. 2008 Jan;108(1):136-9. doi: 10.1016/j.jada.2007.10.004.
- Schwarzer R, Luszczynska A, Ziegelmann JP, Scholz U, Lippke S. Social-cognitive predictors of physical exercise adherence: three longitudinal studies in rehabilitation. Health Psychol. 2008 Jan;27(1S):S54-63. doi: 10.1037/0278-6133.27.1(Suppl.).S54.
- Luszczynska A, Horodyska K, Zarychta K, Liszewska N, Knoll N, Scholz U. Planning and self-efficacy interventions encouraging replacing energy-dense foods intake with fruit and vegetable: A longitudinal experimental study. Psychol Health. 2016;31(1):40-64. doi: 10.1080/08870446.2015.1070156. Epub 2015 Aug 6.
- Luszczynska A, Tryburcy M, Schwarzer R. Improving fruit and vegetable consumption: a self-efficacy intervention compared with a combined self-efficacy and planning intervention. Health Educ Res. 2007 Oct;22(5):630-8. doi: 10.1093/her/cyl133. Epub 2006 Oct 23.
- Luszczynska A, Hagger MS, Banik A, Horodyska K, Knoll N, Scholz U. Self-Efficacy, Planning, or a Combination of Both? A Longitudinal Experimental Study Comparing Effects of Three Interventions on Adolescents' Body Fat. PLoS One. 2016 Jul 13;11(7):e0159125. doi: 10.1371/journal.pone.0159125. eCollection 2016.
Study record dates
Study Major Dates
Study Start
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Estimate)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Other Study ID Numbers
- N106 036 32/2487
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Study Data/Documents
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Study Protocol
Information comments: An abbreviated version of the study protocol
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