Impact of implementation intentions on physical activity practice in adults: A systematic review and meta-analysis of randomized clinical trials

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Impact of implementation intentions on physical activity practice in adults: A systematic review and meta-analysis of randomized clinical trials
Publication Date: 
November, 2018
Plos One

According to motivational theories of behavior, the intention (or motivation) to perform a behavior is closely tied to actually performing this behavior. This is not surprising. As we know from personal life and in our professional practice, without intending to do something it will probably not happen, but we also know that even with high intentions, the desired behavior might not happen. This is referred to as the “intention-behavior gap.” What could be a more familiar example of this gap than intending to exercise, and rarely, actually doing it? Further developments of this theory show that, in addition to intending, it is important to plan the implementation of the intention. “Action planning” refers to planning, very specifically how and when to actually perform a behavior. Planning ahead of time how one will cope when faced with obstacles is referred to as “coping planning.” 

The featured article is a very recent systematic review of studies which tested the effectiveness of interventions developed on the basis of the theory of implementation intentions. The review focused specifically on interventions to promote physical activity, however the conclusions are intriguing and are relevant to other areas of behavior change. The article details how the authors selected the studies, evaluated their quality and what criteria they used to include them in the review. They initially found 507 relevant studies, but after applying the criteria were left with 13. An important criterion was that the study had to be a randomized control trial, which developed interventions using implementation intentions and compared the intervention group to the control group.  

This review (through a meta-analysis of the data in 11 of the 13 articles) demonstrates that interventions using strategies based on implementation intentions were significantly more successful in increasing physical activity, compared to the control group. Another key conclusion as well is that planning the action is important, but so is coping planning (i.e., planning how to deal with unexpected barriers to physical activity if they should appear). Reinforcing the implementation intentions and adjusting the plans after the intervention has completed also added to the effectiveness. 

A very recently published empirical paper (Robinson, Bisson, Hughes, Ebert, & Lachman, 2018) illustrates one study in detail (also designed as a randomized control trial) and comes to similar conclusions.

The above review article evaluates the effectiveness of strategies which use implementation intentions in practice, and illustrates the strength of theory-informed coaching. In the Webinar on February 20, 2019, Dr. Grief will show what this actually means for coaching. He will present his team’s research and explain how he applies the ideas of the intention-action gap in coaching practice. We are fortunate that Dr. Greif will also be making available a guide for applying the practices, informed by the intention-behavior gap theory to coaching, to webinar participants. Additionally, he invites coaches to try these practices for several weeks, after which we will convene a seminar to share experiences and discuss the usefulness of the theory and techniques.   

Robinson, S. A., Bisson, A. N., Hughes, M. L., Ebert, J., & Lachman, M. E. (2018). Time for change: using implementation intentions to promote physical activity in a randomised pilot trial. Psychol Health, 1-23. doi: 10.1080/08870446.2018.1539487

Silva, M., Sao-Joao, T. M., Brizon, V. C., Franco, D. H., & Mialhe, F. L. (2018). Impact of implementation intentions on physical activity practice in adults: A systematic review and meta-analysis of randomized clinical trials. PLoS ONE, 13(11), e0206294. doi: 10.1371/journal.pone.0206294

Astract from authors: 

Objective: The aim of this study was to verify the efficacy of using theory-based strategies on implementation intentions in promoting physical activity (PA) among adults.

Methods: This review was conducted in accordance with the PRISMA recommendations. The search was carried out in seven electronic databases (ILACS, PubMed, SciELO, Cochrane, Web of Science) and two searches of the “grey literature” were performed (Openthesis and OpenGrey). Randomized clinical trials (RCT), published up to September 2016, were considered eligible for this study. Two reviewers independently and systematically evaluated
the eligibility criteria, and performed data extraction. A meta-analysis was performed for the purpose of comparing the effect between the intervention and control groups. The effect sizes were grouped in two subgroups with the purpose of more accurately verifying the effect caused by reinforcing the implementation intentions strategy, and using the inverse variance statistical method with random effects models to estimate the main effect of the implementation intention strategy on the PA behavior. Heterogeneity among the  was evaluated by using I-square statistics, and the Jadad scale to evaluate the quality included papers.

Results: The search resulted in 12,147 records, of which 13 RCTs were considered eligible for this review. Sample age ranged from 18 to 76 years, and participants had conditions such as medullary lesion, coronary disease, obesity, diabetes mellitus, sedentarism or occupational stress. When the summary of the effect was analyzed in the meta-analysis, the result found in the subgroup with reinforcement of the implementation intentions strategy was 0.25 (IC 95% = 0.05–0.45) in favor of the intervention group. This demonstrated that application of the implementation intentions strategy was capable of increasing PA practice in the participants of these studies, in comparison with others that did not use this reinforcement.

Conclusion: The findings of this review indicated that application of the theory of implementation intentions promoted PA behavior among the adults who received reinforcement of this strategy. The systematic review protocol was registered in the PROSPERO database under the number

PLoS ONE 13(11): e0206294.

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