Exploring Common and Novel Actualized Affordances of Fitbit: Mixed Methods Study

Although fitness apps could promote healthier lifestyles, evidence on the effectiveness of app-based interventions remains inconsistent. Previous studies have used affordance theory to identify the factors that generate exercise-related value for users. However, many fitness app affordance studies have examined multiple fitness apps collectively, assuming similar design intentions across platforms. Moreover, most have relied on predefined affordances rather than investigating emergent or novel ones that may reveal unique user-fitness app interactions.

This study aimed to identify the common affordances actualized by Fitbit users and uncover novel affordances that emerge from their interactions with this specific app, thereby extending the understanding of how affordances contribute to user engagement and health outcomes.

We used a 2-stage mixed methods design. First, a cross-sectional web-based survey was conducted with 442 US-based Fitbit users engaging in regular exercise. The participants selected affordances from a list identified in prior literature and could report additional affordances in open-text responses. To corroborate and extend the survey findings, 15,000 user reviews were collected from the Google Play Store, of which 2674 (17.8%) comments were automatically categorized into affordance themes and 1182 (7.9%) were manually validated as relevant. Reviews were thematically classified into affordance categories via a generative pretrained transformer-based approach guided by survey-identified affordances.

The survey revealed that the most frequently actualized affordances were updating (351 participants and 749 review mentions; total=1100) and reminding (319 participants and 143 mentions; total=462), underscoring Fitbit's role in tracking progress and sustaining routines. Competing (99 participants and 88 mentions; total=187) and rewards (133 participants and 32 mentions; total=165) highlighted gamification, whereas comparing (151 participants and 8 mentions; total=159) and guidance (118 participants and 25 mentions; total=143) reflected benchmarking and instructional support. Other affordances such as searching (135 participants and 2 mentions; total=137), encouraging (75 participants and 19 mentions; total=94), and watching others (68 participants and 3 mentions; total=71) were less common, whereas recognizing (58 participants and 0 mentions; total=58) and self-presentation (47 participants and 1 mention; total=50) were the least common. The novel affordances included encouraging others (14 participants and 1 mention; total=15), accountability (3 participants and 9 mentions; total=12), and self-comparison (3 participants and 5 mentions; total=8).

Most Fitbit users actualized updating and reminding affordances, whereas a limited number of users actualized the other affordances. Moreover, few Fitbit users actualized novel affordances that reflect self-regulation, an extension of social connection, and personal meaning. This study emphasizes that Fitbit should focus on core tracking and reminding for most users while providing optional features that foster guidance, community, accountability, and personal relevance. Designing features that facilitate the actualization of common and novel affordances may improve app effectiveness and, ultimately, the health benefits of fitness technologies.