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

ObjectiveThe aim of this study was to verify the efficacy of using theory-based strategies on implementation intentions in promoting physical activity (PA) among adults.MethodsThis review was conducted in accordance with the PRISMA recommendations. The search was carried out in seven electronic databases (LILACS, 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 studies was evaluated by using I-square statistics, and the Jadad scale to evaluate the quality of included papers.ResultsThe 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.ConclusionThe 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 CRD42018090482.

研究目的：本研究旨在验证基于理论的执行意图（implementation intentions）策略，在促进成年人群体身体活动（physical activity, PA）方面的有效性。
方法：本综述严格遵循PRISMA声明开展。检索共覆盖7个电子数据库（LILACS、PubMed、SciELO、Cochrane、Web of Science），同时针对灰色文献开展了2次检索（Openthesis与OpenGrey）。本研究纳入2016年9月及之前发表的随机对照试验（randomized controlled trial, RCT）。由2名研究者独立、系统地完成纳入标准评估与数据提取工作。为对比干预组与对照组的效应差异，本研究开展了Meta分析。为更精准地验证强化执行意图策略所产生的效应，本研究将效应量划分为两个亚组，并采用逆方差统计法结合随机效应模型，估算执行意图策略对身体活动行为的总体效应。采用I²统计量评估研究间异质性，并通过Jadad量表评价纳入文献的质量。
结果：本次检索共获取12147条记录，最终纳入13项符合标准的随机对照试验。研究样本的年龄跨度为18至76岁，参与者涵盖脊髓损伤、冠心病、肥胖、糖尿病、久坐状态或职业性压力等人群。Meta分析的效应合并结果显示，强化执行意图策略亚组的效应量为0.25（95%置信区间：0.05~0.45），结果支持干预组。这表明，相较于未采用该强化策略的对照组，执行意图策略的应用可有效提升研究参与者的身体活动水平。
结论：本综述结果表明，对成年人群应用执行意图理论并强化该策略，可有效促进其身体活动行为。本系统综述的研究方案已在PROSPERO数据库注册，注册号为CRD42018090482。