The FOOTLOOSE App: Evaluation of a Gamified App-Based Exercise Intervention for Children and Adolescents with...

A physically active lifestyle is crucial for long-term cardiovascular health; however, access to supervised exercise programs for children and adolescents with congenital heart disease (CHD) remains limited. Although prior digital exercise interventions for this population have demonstrated safety and feasibility, adherence has often been low. Mobile health approaches integrating gamification may enhance motivation and engagement, particularly among young "digital natives." FOOTLOOSE is an app-based home exercise program developed specifically for children and adolescents with CHD. This study aimed to evaluate user experience, usability, and perceived impact using a multimethod approach.

Children and adolescents aged 10-18 years with simple, moderate, or complex CHD were recruited between July and December 2025 mainly during routine outpatient visits at the TUM Klinikum Deutsches Herzzentrum. Participants used the FOOTLOOSE app in their daily lives over a two-week period. Evaluation included semi-structured qualitative interviews and standardized questionnaires assessing physical activity self-efficacy, enjoyment of physical activity (PACES-S), user experience (UEQ), and health-related quality of life (KINDL^®). Interviews were conducted digitally, transcribed verbatim, and analyzed using qualitative content analysis according to Kuckartz until thematic saturation was reached.

A total of 22 participants (mean age 13.4 ± 2.3 years; 54.5% female) were included. Overall, the FOOTLOOSE app was perceived positively, with participants highlighting enjoyment, intuitive usability, and personalized workout creation. Participants contributed diverse and creative suggestions for further app development, particularly regarding more advanced gamification features (e.g., games or rankings). Most participants reported self-perceived increase in physical activity during the intervention period (n = 15). UEQ scores (mean ± SD) were as follows: attractiveness (1.3 ± 0.8), perspicuity (1.7 ± 1.1), efficiency (1.2 ± 0.9), dependability (1.4 ± 0.7), stimulation (1.0 ± 1.1), and novelty (0.6 ± 1.0).

This study demonstrates the feasibility and user acceptance of a gamified, app-based home exercise program for children and adolescents with CHD. User-centered feedback highlights important directions for iterative refinement, particularly regarding age-appropriate and engaging gamification elements. These findings provide a foundation for future studies evaluating long-term engagement and effectiveness in larger samples.