Risk identification and improvement strategies for BMI and physical fitness and health grade cross-classification: a cross-sectional study based on Chinese college students

The BMI-PFAH cross-classification framework effectively distinguishes diverse risk profiles among university students, revealing hidden risk populations (normal BMI but failing fitness) that traditional BMI-based assessments might overlook. Based on these findings, targeted interventions should include weight management while maintaining fitness for the obesity-pass group, anaerobic and speed training for the normal-fail group, and comprehensive improvements in cardiopulmonary function, muscular strength, and flexibility for overweight/obesity-fail groups. This framework provides a practical basis for developing evidence-based health education and personalized intervention strategies in higher education settings.