Relationship between body mass index and physical fitness of children and adolescents in Xinjiang, China: a cross-sectional study

Abstract

Background Xinjiang is an economically underdeveloped area in China, but the obesity rate of children and adolescents is increasing year by year. Physical fitness and body mass index (BMI) are very important factors for healthy development, whereas few studies focus on the relationship between them in this region. This study aimed to explore the relationship between physical fitness and BMI of children and adolescents aged 7 to 18 in Xinjiang. Method A total of 17,356 children and adolescents aged 7–18 years were involved. BMI was divided into five levels by percentiles, from very low to very high. Physical fitness was evaluated by five indicators: grip strength, standing long jump, sit-and-reach, 50 m dash, and endurance running. Single-factor analysis of variance was used to compare the Z-scores of the five physical fitness indicators among different BMI levels for the four age groups by gender. A nonlinear quadratic regression model was used to evaluate the relationship between BMI and each indicator in the four age groups. Result There is a significant correlation between the five health-related indicators (grip strength, standing long jump, sit and reach, 50 m dash, endurance run) at two age groups (13-15 yrs., 16-18 yrs) of children and adolescents in Xinjiang, China. The range of the Pearson coefficient is 0.048 ~ 0.744. For the other two age groups (7-9 yrs., 10-12 yrs.,) significant correlations are found only in some indicators, and the Pearson coefficient ranges from 0.002 to 0.589. The relationship between BMI and physical fitness presents an U-shaped or inverted U-shaped curve in most age groups(R2 ranges from − 0.001 to 0.182. Children and adolescents with normal BMI score higher on physical fitness tests, and boys (R2 ranges from − 0.001 to 0.182) are more pronounced than girls (R2 ranges from 0.001 to 0.031). Conclusion Children and adolescents with a BMI above or below the normal ranges have lower physical fitness than those with normal BMI. BMI and physical fitness have an U-shaped or inverted U-shaped curve relationship, and the impact is more evident in boys than girls. Targeted actions such as improving the quality of physical education classes, advocating students to keep a balanced diet and physical exercise should be taken designedly.

Association between weight-adjusted-waist index and cardiovascular diseases: a cross-sectional study based on RaNCD cohort data

“…In a prospective study involving a Chinese population, Ding et al discovered a non-linear positive relationship between CVD mortality and WWI [27]. A cross-sectional study on 23,389 participants of the National Health and Nutrition Examination Survey (NHANES) has also shown that the prevalence of stroke increases signi cantly with increasing WWI [17]. Our study was also consistent with previous studies and indicated a positive association between WWI and the odds of CVD.…”

“…This index assesses central obesity by taking into account both muscle and fat mass, and it is calculated by dividing WC by the square root of body weight [14,15]. Several studies have reported a positive association between WWI and chronic diseases such as CVD, stroke, non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease [16][17][18][19]. However, a comprehensive study in this eld has not been conducted in Iran.…”

Secular trends in physical fitness of rural Chinese children and adolescents aged 7–18 years from 1985 to 2019

“…During the period 2000-2019, the BMI of boys and girls in all age groups increased and the increase accelerated, especially in those aged 16-18 years. It has been shown that both higher and lower BMI can have a detrimental effect on physical fitness 22,59 . Overweight and obesity individuals tend to perform less physical activity, have longer screen time, consume more calories 60 and have a substantial decrease in physical activity.…”

Mobile Gamers versus Non-gamer students’ endurance levels via Beep and 3-minute step test

“…The findings of [44] have also found that BMI was negatively associated with cardiorespiratory fitness. Likewise, the study of [45] have also reported that adolescents whose body mass index (BMI) is either above or below the average range are less physically fit than their normalweight peers. Contrastingly, the findings of [46] have reported that BMI is not significantly associated with endurance level for volleyball athletes during the COVID-19 pandemic.…”