Abstract
BACKGROUND: Mobile health (mHealth) applications have the potential to support adolescents' self-management of knee pain. However, ensuring adherence remains a barrier when designing mHealth concepts for adolescents. OBJECTIVE: This study aimed to explore barriers and facilitators for adhering to mHealth interventions to inform design principles. METHODS: Think-aloud tests were conducted with 12 adolescents (aged 12.5 years median) with knee pain, using a low-fidelity prototype. The prototype was informed by the authors previous work, rapid prototyping sessions with seven health professionals, and synthesis via the Behavioral Intervention Technology Model. The think-aloud tests were video recorded and analyzed thematically to identify design principles. RESULTS: The analysis based on user testing with adolescents with knee pain identified three themes: "user experience and feedback," "contextual challenges," and "new features" and nine subthemes. Adolescents were able to use mHealth behavioral features such as self-tracking, goal setting, education, and data visualization to capture and reflect on their knee pain developments, which facilitated use. However, adolescents struggle with timing interventions, breaking down management behaviors, and biases towards interventions were identified as internal threats to adherence. Competing activities, parental meddling, and privacy concerns were external adherence barriers. Twelve design principles were identified for integrating these insights into mHealth designs. CONCLUSION: Participants' motivations for adherence were influenced by internal and external factors. While adolescents were able to use mHealth behavioral features to capture and reflect on knee pain developments, understanding how to accommodate adolescents' cognitive abilities, competing activities, and need for independence is quintessential to enhance adherence in everyday contexts.