Changes in body composition and low-grade inflammation status in boys during a basketball afterschool program for three years Castro-Collado, Cristina Jurado-Castro, Jose Manuel Gil-Campos, Mercedes de la Cruz Rico, María Pastor Villaescusa, Belén Quintana-Navarro, Gracia María Llorente Cantarero, Francisco Jesús Sport Childhood Health Regular exercise during childhood is crucial for optimal growth. However, evidence on its long-term effects on physical fitness, inflammation and metabolic status remains limited for this period of life. To assess the longitudinal effects of a three-year basketball program on physical fitness, body composition, metabolic and inflammatory markers in prepubertal boys. Seventeen boys (8–13 years) participated in an after-school basketball program with 96 weeks of training across three academic years. At baseline and follow-up, assessments included anthropometry, body composition measured by bioimpedance, physical fitness using cardiorespiratory and strength tests, and fasting blood biomarkers. This study was registered at ClinicalTrials.gov (identifier: NCT07007624; 06/06/2025). At the end of the program, body fat remained stable, while fat free mass increased in upper and lower limbs (e.g., +1.5 kg in lower limbs, p<0.05). Physical fitness improved in endurance (Course Navette: +4.2 min, p<0.01) and strength tests. Inflammatory markers showed elevations in PAI-1 (+86%, p<0.05), MCP-1 (+23%, p<0.01), IL-8 (+400%, p<0.001), and TNF-α (+98%, p<0.05), possibly reflecting increased training intensity. Long-term basketball training improved physical fitness and lean mass in prepubertal boys. However, the small sample size and absence of a control group warrant cautious interpretation and underscore the need for further research. 2025-11-17T09:29:36Z 2025-11-17T09:29:36Z 2025-11-06 journal article Castro-Collado, C., Jurado-Castro, J.M., Gil-Campos, M. et al. Changes in body composition and low-grade inflammation status in boys during a basketball afterschool program for three years. Sci Rep 15, 38916 (2025). https://doi.org/10.1038/s41598-025-22628-5 https://hdl.handle.net/10481/108024 10.1038/s41598-025-22628-5 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Springer Nature