Comparative research on the relationship between body mass index and physical fitness index among the Uygur, Kazakh and Han ethnic college students

To understand the nutritional status and physical fitness of the Uygur, Kazak and Han ethnic college students, and to investigate the nonlinear relationship between BMI and physical fitness indexes in different ethnic groups. A total of 3 600 Uygur, Kazakh and Han students majoring in non-sports in a university in Xinjiang Uygur Autonomous Region in 2021 were selected by stratified random cluster sampling method. Height, weight, vital capacity, 50 m running, standing long jump, sit-and-reach, sit-up/pull-up and endurance running were measured. Body mass index (BMI), standardized Z score of each test score and physical fitness index (PFI) were calculated. The data were analyzed by Chi-square test, single factor analysis of variance, and nonlinear quadratic regression. Prevalences of overweight (16.00%) and obesity (8.08%) of the Han college students were significantly higher than those of the Uygur (11.83% and 4.08%) and Kazakh (13.58% and 4.58%). Prevalence of low weight in the Uygur (11.92%) was the highest,