A co-designed website (TeenFit) to promote physical activity in adolescents through mobile apps: a study protocol

IntroductionAdolescence is a critical period marked by physiological and psychological changes that influence long-term health. Establishing healthy behaviors, particularly regular physical activity, is essential during this stage; however, around 80% of young people do not meet the World Health Organizations physical activity recommendations. Digital technologies offer promising opportunities to promote health among youth, yet most physical activity apps lack scientific validation and usability. Unlike psychology, which has validated repositories to guide users in selecting mental health apps, physical activity lacks validated repository platforms, especially for adolescents. The project has a twofold aim: (1) to co-design a website, named the TeenFit website, that facilitates the selection of physical activity apps tailored to each adolescents individual needs and preferences; and (2) to investigate the barriers and facilitators for the implementation of the TeenFit website in real-world settings. Methods and analysisAdolescents and other stakeholders (i.e., caregivers, educators, and health professionals) will be engaged in the development of the TeenFit website app finder through a participatory design approach that involves three workshops, encompassing both a development phase and an implementation phase. Approximately 10-12 participants per stakeholder group will take part in smaller working groups (i.e., workshops) to collaboratively contribute to the co-design of the TeenFit website. TeenFit will include mobile applications available in the Spanish market, developed in both English and Spanish. These applications are currently being identified through two ongoing systematic reviews. In addition to qualitative data gathered during the audio- and video-recorded workshops, quantitative data will be collected on participants co-design experiences and the acceptability of the TeenFit website. Data analysis will involve descriptive statistics, qualitative content analysis for describing participants perspectives on what aspects (i.e., content, features, and layout) are important for the design of the website, and reflexive thematic analysis to identify barriers and facilitators to implementation. Ethics and disseminationThe study was approved by the Research Ethics Committee in the province of Malaga (Spain) (REC ref: SICEIA-2024-003172). Research findings will be disseminated primarily via national and international conferences and publication in peer-reviewed journals. Patient and public involvement will inform further dissemination activities. Strengths and limitations of this studyO_LIThe major strength of the study is that it draws on both qualitative and quantitative data to generate meaningful insights into the co-design and implementation of the TeenFit website, including participants co-design experiences, preferences, sociodemographic characteristics, the websites acceptability, and the barriers and facilitators to its implementation. C_LIO_LILimitations include the use of a convenience sampling approach, which may lead to uneven demographic representation. A transparent reporting of participant characteristics will nevertheless allow readers to assess whether our findings are transferable to other settings. C_LIO_LIOffering one-to-one online participation alongside in-person workshops may mitigate accessibility barriers, though it could affect the dynamics of group interaction compared with fully in-person sessions. C_LI