Designing, Developing, and Evaluating a Stakeholder-Informed Mobile App to Promote Physical Activity in Children

<b>Background</b>: Prolonged sedentary behavior and associated obesity are recognized risk factors for poor health across the lifespan. Globally, data show that many children and adolescents aged 5 to 17 significantly increased their sedentary behaviors during the COVID-19 pandemic, failing to meet recommended physical activity levels and reporting increased smartphone use. While mobile devices and video games have been traditionally linked to physical inactivity, formats like exergaming, which combine gameplay with gross motor activity, offer potential to promote physical activity. However, many digital health tools for children are developed without incorporating feedback from key stakeholders and end-users (e.g., children, teachers, and guardians). Therefore, this paper, within the Walk around the Earth (E-Walk) project, describes a prospective study that aims (1) to identify the most influential factors or characteristics affecting engagement with and usability of a mobile application promoting physical activity among primary school students; (2) to develop a mobile application for children based on the identified factors and characteristics. <b>Methods</b>: This project will use a group concept mapping approach to identify the most influential features/factors/characteristics affecting engagement with and usability of an app. By involving primary stakeholders (e.g., children, teachers, guardians, and physical activity experts), the project seeks to align the app's features with primary end-user needs and motivations. Following the app's development, its effectiveness in increasing physical activity levels and reducing sedentary behaviors will be evaluated through a mixed-method design, incorporating anthropometric data, validated physical activity questionnaires (Physical Activity Questionnaire for Older Children (PAQ-C) and International Physical Activity Questionnaire (IPAQ)), and engagement metrics. <b>Conclusions</b>: The E-Walk project integrates participatory design with educational content and activity-based challenges, representing a multidimensional strategy for promoting health and learning in primary school students. Ultimately, this study contributes to the development of user-informed digital interventions that support sustainable behavioral changes, in line with broader goals of child well-being and digital health promotion.