Associations between physical fitness and idiopathic scoliosis in Chinese adolescents: A case-control study

Adolescent idiopathic scoliosis (AIS) screening and physical fitness testing are important components of health management for Chinese adolescents. This study aimed to evaluate the independent associations between prior-year physical fitness scores and AIS, with sex-stratified analysis. This case-control study was conducted in Jincheng, Shanxi Province, China, from March to October 2025, including 401 cases of AIS aged 13–18 years and 820 healthy controls matched to the cases by age and sex. Multiple logistic regression was used to evaluate the independent associations between prior-year physical fitness and AIS. In the male subgroup, for each 1 kg/m 2 increase in BMI, the odds of AIS decrease by 8.2%; for each 10-point increase in vital capacity, 50 m run, and sit-and-reach score, the odds of AIS decrease by 14.4%, 16.3%, and 23.8%, respectively. In the female subgroup, for each 1 kg/m 2 increase in BMI, the odds of AIS decrease by 9.2%; for each 10-point increase in vital capacity and standing long jump score, the odds of AIS decrease by 12.7% and 9.6%, respectively. This study suggests incorporating physical fitness monitoring into the AIS screening and preventive strategies. • Prior-year physical fitness was associated with adolescent idiopathic scoliosis. • Males relate to body mass index, vital capacity, sit-and-reach, and 50-m run. • Females relate to body mass index, vital capacity, and the standing long jump. • Findings suggest incorporating physical fitness monitoring into scoliosis screening.