JMIR Publications

ABSTRACT

Background:

While fitness applications have the potential to promote healthier lifestyles when used consistently, research suggests that user engagement often remains short-lived. Previous studies have employed affordance theory to identify the core benefits of these applications; however, many 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.

Objective:

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

Methods:

We employed a two-stage, mixed-method design. First, a cross-sectional web-based survey was conducted with 442 U.S.-based Fitbit users engaging in regular exercise. The participants selected from a list of affordances 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 2,674 comments were automatically categorized into affordance themes and 1,182 were manually validated as relevant. Reviews were thematically classified into affordance categories via a GPT-based approach guided by survey-identified affordances.

Results:

The survey revealed that the most frequently actualized affordances were updating (351 participants; 749 review mentions, total = 1100) and reminding (319 participants; 143 mentions, total = 462), underscoring Fitbit’s role in tracking progress and sustaining routines. Competing (99 participants; 88 mentions, total = 187) and rewards (133 participants; 32 mentions, total = 165) highlighted gamification, whereas comparing (151 participants; 8 mentions, total = 159) and guidance (118 participants; 25 mentions, total = 143) reflected benchmarking and instructional support. Other affordances, such as searching (135 participants; 2 mentions, total = 137), encouraging (75 participants; 19 mentions, total = 94), and watching others (68 participants; 3 mentions, total = 71), were less common, whereas recognizing (58 participants; 1 mention, total = 59) and self-presentation (47 participants; 4 mentions, total = 51) were least common. The novel affordances included encouraging others (14 participants; 1 mention, total = 15), accountability (3 participants; 9 mentions, total = 12), and self-comparison (3 participants; 5 mentions, total = 8).

Conclusions:

Most Fitbit users actualized common affordances such as updating and reminding but also extend engagement through novel affordances that reflect self-regulation, social connection, and personal meaning. This study emphasizes that Fitbit should focus on core tracking and reminding for majority of users while providing optional features that foster accountability, community, and personal relevance. Designing both common and emergent affordances may maximize long-term engagement and, ultimately, the health benefits of fitness technologies.