Effectiveness of a school-based intervention using alternative sports to improve physical and motor skills in elementary school students (RENUÉVATE Project): study protocol for a randomized controlled trial.

Background: Physical inactivity and low enjoyment of physical education during childhood represent a significant public health problem. Although schools are a key setting for promoting active lifestyles, physical education instruction continues to focus largely on traditional sports, which may limit student participation and engagement. In this context, alternative sports emerge as an innovative and potentially more inclusive pedagogical strategy. Therefore, the objective of this study is to evaluate the effectiveness of an alternative sports intervention in the school setting, compared to standard physical education, on physical fitness, body composition, motor competence, and enjoyment of physical activity among elementary school students. Methods: A cluster-randomized controlled trial will be conducted among 11- to 12-year-old schoolchildren. Schools will be selected at random, and within each school, two classes from the same grade will be assigned to the intervention or control groups. The intervention will consist of an eight-week instructional unit (16 sessions) based on four alternative sports (flag football, ultimate frisbee, korfball, and kin-ball) taught using the Teaching Games for Understanding approach. The control group will continue with the regular physical education curriculum. Physical fitness, motor competence, and enjoyment of physical activity will be assessed as primary outcomes, while physical activity levels and body composition will be considered secondary outcomes. All variables will be assessed before and after the intervention. Primary analyses will follow the intention-to-treat principle using mixed-effects models to account for clustering (students within schools). The effects of the intervention will be estimated using the group × time interaction. Analyses will be performed using SPSS v28 and R v4.3. Discussion: This protocol addresses significant gaps in the literature on school-based interventions using alternative sports. It is expected that the experimental design, together with a structured intervention that can be replicated by teachers, will generate robust evidence on the physical, motor, and affective-motivational mechanisms associated with this pedagogical approach. The anticipated findings may serve as a basis for future curricular decisions and educational policies aimed at promoting physical activity and health during school-age years. Clinical trial registration: ClinicalTrials.gov, identifier NCT07313267.