Factors associated with physical fitness and disparities in population segments among older adults: A cross-sectional study

Objectives: This study aimed to investigate the factors associated with physical fitness and disparities in population segments among older adults, using data from the National Physical Fitness Surveilling Survey of China. Study design: A cross-sectional study. Methods: A total of 13524 older adults aged 60–79 years were involved in the study. Participants completed physical fitness assessments encompassing body fat percentage, lung capacity, high leg raise in place, grip strength, seated forward bending, 30-s sit-to-stand test, single-leg standing with eyes closed, and choice reaction time. A profile analysis model was constructed by feature extraction, label design and clustering using principal component analysis and k-prototypes. Factors associated with physical fitness were analyzed using ordered probit regression, and within-group differences were evaluated through the bootstrap method. Results: The older adults were categorized into four clusters based on the clustering results (Cluster I: n = 2728, Cluster II: n = 6067, Cluster III: n = 4189, Cluster IV: n = 540). Significant positive associations were identified between moderate-to-vigorous transport-related activities (α = 0.001, p