Changes in body composition and low-grade inflammation status in boys during a basketball afterschool program for three years

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.