The Use of Competition in a School-based Intervention for Increasing Cardiorespiratory Fitness in Adolescents

Regular physical activity offers numerous physical, psychological, and cognitive health benefits. However, physical inactivity among adolescents remains a global concern, with 81% of 11- to 17-year-olds failing to meet WHO\'s recommendation of at least one hour of moderate- to vigorous-intensity activity daily. This inactivity contributes to immediate and long-term health risks, as many non-communicable diseases (NCDs) in adulthood are linked to behaviors established during adolescence. Promoting healthy lifestyles early is crucial for lifelong health and disease prevention. One significant barrier to effective school-based physical activity programs, such as High-Intensity Interval Training (HIIT), is maintaining student motivation. Low engagement often results in poor adherence. Integrating competition-focused on effort rather than performance-may enhance student participation and make HIIT interventions more effective and easier to implement. This study will evaluate the impact of competition on the Burn 2 Learn - Mallorca (B2L-M) program, targeting adolescents aged 15-18. The intervention aims to determine whether competition improves engagement and outcomes compared to non-competitive groups. The primary outcome is cardiorespiratory fitness (CRF), while secondary outcomes include muscular strength, physical activity levels, body composition, mental health (stress and sleep quality), behavior change mediators (self-efficacy, motivation), on-task behavior, blood pressure, and sitting posture. The B2L-M intervention will involve a 16-week, three-arm cluster randomized controlled trial in Mallorca, Spain, recruiting approximately 360 students from six schools. The program includes teacher-led HIIT sessions twice weekly during physical education, supported by information seminars, a dedicated website, and parental e-newsletters. Outcomes will be assessed at baseline and after 16 weeks.