Factors influencing user's adherence to physical activity applications: A scoping literature review and future directions

Background: Although mobile app-delivered physical activity (PA) interventions have the potential to promote exercise, poor adherence to these apps is a common issue impeding their effectiveness. Gaining insights into the factors that influence PA app adherence is an important priority for app developers and intervention designers. Objective: The objective of this study is to perform a literature review to synthesize the factors influencing PA app adherence and to identify directions for future research in this area. Methods: A scoping review of prior research was conducted to uncover the factors influencing PA app adherence. Seven online journal databases were searched for relevant articles published from January 1, 2014, to December 31, 2018. The initial search identified 5,572 articles. After a screening and eligibility check based on inclusion criteria, 24 articles were finally selected. The definition of PA app adherence in this review could be categorized along four dimensions derived from previous studies: i.e., frequency of PA app usage, intention/motivation to sustain use of the PA app, degree of function use within the PA app, and the duration of PA app usage. Results: Of the 24 included studies (both qualitative and quantitative), 12 studies were conducted in the U.S. The methods and study designs varied considerably, with the study durations ranging from 2 weeks to 24 months. The synthesized evidence indicates that 89 distinct factors influenced PA app adherence, and these could be classified into three categories: Personal Factors (n = 28), Technology Features (n = 53), and Contextual Factors (n = 8). Nine more detailed sub-categories were also compiled. Factors in sub-categories, such as psychological factors, health-related factors and predefined goals, are essential for physical activity behavior change experts to implement interventions. Factors in technology features, including PA tracking, PA goal setting and customization of exercise, are specifically useful for PA app developers or PA intervention designers. Overall, evidence of causal factors was limited. Only 5 of the 24 articles explored causal factors that affect PA app adherence. Furthermore, longitudinal studies with long durations were also limited. Conclusions: Uncovering the factors influencing PA app adherence is critical as it can expand our current knowledge and provide guidance for app-delivered PA interventions, as well as the design of PA apps. This scoping review identified and categorized factors that influence PA app adherence in prior studies. Based on the evidence synthesized, users are paying more attention to the “playfulness” and personalized features of PA apps, in addition to basic functional requirements. Also, app glitches are the most common factors found to negatively influence app adherence. Several important directions for future research are highlighted in this review, especially the design of studies to explore causality.