Evaluating Effectiveness of the FiTeens Intervention for Health Behavior Change in Students: A Study Protocol

(1) Background: Previous school-based interventions have addressed adolescent health behaviors such as physical activity, screen time, and sleep, but have predominantly targeted these behaviors independently rather than simultaneously. The Erasmus+ project FiTeens developed an integrated intervention combining theoretical content, videos, infographics, and interactive tasks to promote multiple health behaviors concurrently. The objective of the current article is to present the protocol for a school-based intervention study designed to examine the effects of the FiTeens program on adolescents' physical activity, screen time, and sleep behaviors. We hypothesize that students receiving the FiTeens intervention will demonstrate increased physical activity, reduced screen time, and improved sleep outcomes compared with students in the control group. (2) Methods: Teachers will be introduced to the FiTeens tools prior to delivering the intervention to students in grades 5-9. Students will participate in an eight-week intervention program combining structured lessons and behavior-change challenges. Primary outcomes include changes in physical activity, screen time, and sleep duration and quality. Secondary outcomes include psychological determinants such as motivation and behavioral intentions. Data will be collected at baseline and at 1-, 3-, and 6-month follow-ups and analyzed using repeated measures ANOVA. (3) Expected results: The study will evaluate whether the intervention may contribute to improvements in health-related behaviors among adolescents, including increased physical activity, reduced screen time, and improved sleep outcomes. (4) Conclusions: The intervention based on FiTeens tools could have the potential to promote healthier lifestyle behaviors among students by increasing physical activity during leisure time, supporting the effective limitation of screen time and enhancing bedtime routines to improve sleep quality.