The association between BMI and health-related physical fitness among Chinese college students: a cross-sectional study

Xiaobin Chen,Jie Cui,Wenjia Peng,Yuyuan Zhang

doi:10.1186/s12889-020-08517-8

Abstract

BackgroundExisting studies reporting on the levels of physical fitness among college students used relatively few fitness tests as a reflection of physical fitness, which could not comprehensively evaluate the levels of physical fitness. Thus, the current study aimed to investigate the cross-sectional relationship between body mass index (BMI) and a physical fitness index (PFI) based on six indicators of fitness in Chinese college students.MethodAnthropometric measurements and six measures of physical fitness (Vital capacity, 50-m sprint, sit and reach, standing long jump, 800/1000-m run, pull-up/bent-leg sit-up) were measured. BMI was calculated to classify individuals into underweight, normal weight, overweight, and obesity groups. Z-scores based on sex-specific mean and standard deviation were calculated, and the sum of z-scores for the six fitness tests was used as a PFI. Three models (a linear regression model, polynomial regression model with a second-order BMI term and a restricted cubic spline regression model) were fitted to discuss the potential relation between BMI and PFI. We compared the models using Akaike Information Criterion (AIC) and R square.ResultsTotally, 8548 freshmen from the years 2014 to 2016 in a medical college completed the physical fitness tests. There was a decreasing trend of physical fitness index from the years 2014 to 2016 (P for trend < 0.01). More male than female students were overweight or obese (23.5% vs. 11.9%), but more female than male students were normal weight (74.7% vs. 64.8%). A restricted cubic spline regression model was superior to linear and polynomial regression model with lower AIC and higher R square.ConclusionsThe relationships between BMI and PFI in college students were non-linear. Underweight, overweight and obese students had poorer performance in physical fitness index than normal weight students. Future prospective, longitudinal cohort studies to identify the causal relations and potential mechanism in a good manner are required.

Highlights

Existing studies reporting on the levels of physical fitness among college students used relatively few fitness tests as a reflection of physical fitness, which could not comprehensively evaluate the levels of physical fitness
More male than female students were overweight or obese (23.5% vs. 11.9%), but more female than male students were normal weight (74.7% vs. 64.8%)
There are a few studies that discussed the association between body mass index (BMI) and several components of physical fitness in children [10] and in adolescents [11]

Summary

Introduction

Existing studies reporting on the levels of physical fitness among college students used relatively few fitness tests as a reflection of physical fitness, which could not comprehensively evaluate the levels of physical fitness. One study performed by Wang et al [3] in Chinese adolescents found that the prevalence of physical activity time less than 1 hour per day was high in students aged 9–22 years. There are a few studies that discussed the association between body mass index (BMI) and several components of physical fitness in children [10] and in adolescents [11]. Hao et al [13] used BMI, vital capacity index, sidestep test and standing long jump to investigate the gender differences in physical fitness. The purpose of this study is to analyze the levels of different physical fitness components in medical school freshmen, and to further evaluate the association between BMI and health-related physical fitness

Objectives

Methods

Results

Discussion

Conclusion