Understanding User Engagement Factors in Reward-Based Walking Apps: Focusing on the Fogg Behavior Model Perspective of the CashWalk

This study examines user-centered design strategies that support sustained engagement with walking-based health reward applications by applying the Fogg Behavior Model (FBM). User perceptions of the CashWalk application were analyzed using 100,940 reviews collected from the Google Play Store between 2017 and 2025. Latent Dirichlet Allocation topic modeling and logistic regression–based sentiment analysis were employed. Seven key themes were identified, including user benefits, app errors, gamification elements, interactive services, point accumulation, usage experience, and advertising. Positive sentiment was associated with exercise, health, and walking, whereas negative sentiment was linked to technical issues, updates, deletion, and pricing. Mapping user-generated content onto FBM components highlights the importance of intuitive UI/UX, automated reward systems, and technical stability, particularly for older adults and digitally vulnerable users. The findings suggest phased design strategies that facilitate a shift from extrinsic to intrinsic motivation to promote sustainable engagement in digital health platforms.