Design and evaluate a digital approach to promote physical activity among adolescents

Thesis Abstract

Physical inactivity among adolescents poses a significant public health challenge, contributing to increased risks of obesity, cardiovascular diseases, and mental health issues. Despite widespread awareness of the benefits of physical activity, engagement levels remain low, particularly within digital-native youth populations. This study aims to design, implement, and evaluate a culturally contextualized digital intervention—specifically a mobile application combined with gamified features—to promote sustained physical activity among adolescents aged 13 to 17 years. The primary objectives are to develop an evidence-based digital platform grounded in Self-Determination Theory and Social Cognitive Theory, assess its usability and acceptability, and empirically examine its effectiveness in increasing duration and frequency of physical activity over a six-month period. The research adopts a mixed-methods, quasi-experimental design, involving a sample of 300 adolescents recruited from urban secondary schools through stratified random sampling. Participants will be divided into an intervention group, that will utilize the digital platform, and a control group receiving standard health education materials. Quantitative data on physical activity levels will be collected via validated self-report questionnaires (e.g., the Physical Activity Questionnaire for Adolescents) and objectively measured using accelerometers at baseline, three months, and six months. Qualitative insights will be gathered through focus group discussions (FGDs) and semi-structured interviews to explore user experiences, perceived barriers, and facilitators. The reliability and validity of instruments will be established through pilot testing and Cronbach’s alpha coefficients exceeding 0.80. Data analysis will involve descriptive statistics to characterize the sample, repeated-measures ANOVA to evaluate changes in activity levels over time within and between groups, and thematic analysis of qualitative data to identify recurrent themes related to user engagement and perceived impact. To understand the influence of theoretical constructs, regression analyses will determine the mediating effects of motivation and self-efficacy on behavioral outcomes. Expected findings include statistically significant increases in physical activity durations among adolescents engaging with the digital intervention, as well as high usability scores and positive perceptions regarding the app’s gamification and social features. It is anticipated that the intervention will demonstrate enhanced motivation and behavioral self-regulation, consistent with the theoretical frameworks. This study will contribute to the existing body of knowledge by providing empirical evidence on the effectiveness of digital, gamified approaches in promoting adolescent physical activity, integrating behavioral theories into practical health technologies, and identifying key factors influencing sustained engagement. It addresses theoretical gaps related to the application of Self-Determination and Social Cognitive Theories in digital health interventions for youth. The main conclusion underscores the potential of tailored mobile health solutions to foster active lifestyles among adolescents, with implications for policymakers, educators, and health practitioners aiming to combat physical inactivity. Recommendations include scaling the intervention within broader school health programs, integrating parental and peer support mechanisms, and exploring long-term sustainability through iterative design based on user feedback. Future research should examine the cost-effectiveness of such interventions across diverse demographic and socioeconomic contexts, and investigate longitudinal outcomes beyond six months to ascertain sustained behavioral change.