Introduction: Physical inactivity is a major global public health issue among young adults (18–30 years old), whose transitions into higher education and the workforce often reinforce sedentary behaviors. Barriers include lack of motivation and monotony. Innovative mHealth strategies integrating Augmented Reality (AR) and gamification are essential to support adherence to World Health Organization recommendations.

Objectives: This project aimed to develop and evaluate a prototype mobile application, Obscura: Urban Mystery, designed to enhance the frequency and intensity of physical activity through an immersive narrative.

Project Description: Following a user-centered co-design process with young adults and Occupational Therapists, a high-fidelity prototype was developed. The user assumes a detective’s role; progression requires "recharging" a virtual device through aerobic and strengthening exercises. Gamification elements (leaderboards, daily challenges) maximize engagement. Preliminary usability testing (n=5) via "think-aloud" protocols confirmed intuitive navigation but suggested refinements in GPS calibration.

Monitoring Methodology: Evaluability will be assessed through a pilot quasi-experimental pre–post study with a convenience sample of 30 university students (inclusion: sedentary lifestyle; exclusion: exercise contraindications). Validated measures include IPAQ-SF (physical activity), WHO-5 (well-being), PSQI (sleep quality), and Borg Scale (perceived exertion), supplemented by smartphone sensor data (pedometer/GPS). Ethical approval and informed consent were secured, including GDPR-compliant encryption for sensitive geolocation data.

Conclusions: Obscura: Urban Mystery offers a promising response to inactivity by combining digital entertainment with health promotion. For Occupational Therapy, it represents a potential therapeutic resource to support meaningful engagement in leisure and health-management occupations, encouraging active participation and occupational balance.