Psychological mechanisms underlying the relationship between commercial physical activity app use and physical activity engagement: A cross-sectional study.

Purpose: Previous studies have indicated a relationship between the use of commercial physical activity apps (e.g., Fitbit, Strava) and physical activity engagement. Use of social components of such apps, in particular app-specific communities (connecting with other app users) and existing social media platforms (e.g., Facebook) have the potential to enhance physical activity. This study aimed to explore the psychological mechanisms underlying the relationship between the use of commercial physical activity apps (and their social components) and physical activity engagement. Method: An online cross-sectional survey assessed physical activity, engagement with commercial physical activity apps (and their associated social components), and psychological constructs (social support, self-efficacy, motivation, trait competitiveness, trait social comparison). The SPSS macro PROCESS was used to conduct mediation (Model 4) and moderation (Model 1) analyses. Alpha was set at 0.05. Results: Participants were 1206 adults aged 18-83 years (Mage = 34.0 ± 13.5 years, 88.5% female).App use was positively associated with physical activity engagement (p < .001, d = 0.40). The relationship between app use and physical activity was fully mediated by social support (b = 8.7, CI 3.3, 14.7), self-efficacy (b = 21.7, CI 14.2, 30.7), intrinsic motivation (b = 9.4, CI 1.4, 17.5) and identified regulation (b = 34.8, 2, CI 24.7, 48.5). Trait competitiveness (b = 25.3, p < .05) but not trait social comparison (b = 15.6, p = .372) moderated the relationship between app use and physical activity. In addition, the relationships between features of app-specific communities (providing/receiving encouragement) and existing social media platforms (sharing posts, providing/ receiving encouragement and engagement in comparisons) influenced physical activity via social support, self-efficacy, and identified regulation. Conclusions: The relationship between the use of commercial physical activity apps (and their social components) and physical activity is underpinned by social support, self-efficacy and motivation (intrinsic and identified). This highlights that commercial physical activity apps may be fundamental in promoting physical activity, given their capacity to influence psychological constructs associated with physical activity. Future research should further explore the use of commercial physical activity apps and their associated social components to increase physical activity engagement.