Associations between Physical Fitness Index and Body Mass Index in Tibetan Children and Adolescents in Different High-Altitude Areas: Based on a Study in Tibet, China

Using structural equation modeling to examine correlations between health-related physical fitness and cell health among Chinese college students

INTRODUCTION

College students' physical fitness is likely to be directly related to their cells' health. However, there is a lack of literature on whether the relationship between cell health and college students' physical fitness is direct or indirect. This study used a structural equation modeling (SEM) approach to investigate the connection between cell health and college students' physical fitness.

METHODS

This cross-sectional study collected data from 838 volunteers (502 males and 336 females, average age of 18.74 ± 1.5 years) who were college students from the Shandong province of China in July 2023. Initially, we obtained anthropometric measurements and conducted physical fitness tests on the students. Then, we performed Pearson correlation analysis and principal component analysis to screen variables and explore potentially influencing factors. Finally, we examined associations between the variables and determined whether there were direct or indirect influences among factors using SEM.

RESULTS

The results revealed a significant correlation between the cell health factor and the muscle strength factor (path coefficient = 0.97; p < 0.001) as well as the fat obesity factor (path coefficient = -0.52; p < 0.001). The cardiovascular factor exhibited a weak correlation with the cell health factor (path coefficient = 0.11; p < 0.01). Moreover, the cardiovascular factor acted as a mediating variable between the muscle strength factor and the cell health factor, with a positive correlation observed between the muscle strength factor and the cell health factor (path coefficient = 0.40; p < 0.001).

CONCLUSION

These findings suggest that cell health is indicative of muscle strength and cardiorespiratory fitness. Our findings demonstrate that assessing the cell health of college students can be a valuable method for evaluating their overall health.

Is the COVID-19 epidemic affecting the body mass of Chinese teenagers? - A longitudinal follow-up study

Background

After the spread and outbreak of COVID-19 worldwide, the learning, lifestyle, and health level of young individuals have been immensely impacted. With regard to the existing studies, the development trend of adolescents' body shape in the late COVID-19 period is not sufficiently analyzed, and relevant targeted investigation is lacking. This study aimed to explore the body mass index (BMI) changes of 6-14 years-old adolescents before and after the COVID-19 epidemic, and to provide a reference for promoting the continuous enhancement of adolescent health.

Methods

The BMI and related data pertaining to 93,046 individuals from 2019 to 2022 were collected by cluster sampling, and changes in the BMI Z score and detection rate of overweight and obese adolescents before and after the epidemic were analyzed. Furthermore, the trend of obesity rates among adolescents in Jinan from 2019 to 2022 was analyzed using a logistic regression analysis model.

Results

The one-way ANOVA models indicated that the BMI Z score of 6-14 years-old adolescents in 2020 significantly increased compared to 2019 (p < 0.01), and decreased in 2021 and 2022; in 2020, the obesity rate of adolescents exhibited a significant increase; however, the rate decreased after being controlled in 2021 and 2022. The normal-body size proportion continued to rise (p < 0.01), and adolescents of different age groups and genders exhibited similar development trends; the results of the logistic regression analysis indicate that there was a significant increase in obesity rates in 2020, adolescents of different age groups and genders exhibited similar development trends (p < 0.05).

Conclusion

This study demonstrated that the COVID-19 epidemic impacts the BMI and obesity detection rate of adolescents. Adolescents from different age groups and genders exhibited similar development trends.

Striking a balance: how long physical activity is ideal for academic success? Based on cognitive and physical fitness mediation analysis

Balancing physical activity and studying is an important issue facing Chinese teenagers. Therefore, numerous studies have found that engaging in physical activity can promote academic performance among students. However, what is the optimal duration of physical activity? This study used data from the China Education Panel Survey, with a sample size of 18,009 valid respondents. General linear regression analysis was conducted using Stata 17 software to evaluate the effects of different durations of physical activity, cognitive ability, and physical Fitness on academic performance among adolescents. Furthermore, the "Bootstrap Mediation" method and the "Maximum Likelihood Estimation" method were used to analyze whether physical health and cognitive ability have significant mediating effects. The present study reveals the following findings: (1) There exists a non-linear relationship between students' academic performance and the duration of physical exercise. The greatest improvement in academic performance is observed when the exercise duration reaches 2 hours. (2) Physical exercise can enhance students' academic performance by promoting physical health and cognitive abilities. (3) Gender heterogeneity is observed, with the optimal exercise duration for male students being 2 hours, while female students exhibit the highest academic performance when exercising for one hour. This study provides theoretical guidance for research on adolescents' participation in physical Activity and improving academic performance, enabling adolescents to engage in physical Activity more scientifically and rationally.

Body Mass Index and Physical Fitness among Chinese Adolescents Aged 15-18: A Cross-Sectional Study of Gender Differences

OBJECTIVE

The aim of this study is to examine the relationship between varying levels of obesity and physical fitness test scores among Chinese adolescents, while also investigating gender differences in physical fitness and overall health. Data on height, weight, 50 m sprints, 1000/800 m runs, standing long jumps, sit and reach exercises, pull-ups/bent-leg sit-ups, and additional variables were collected from the DYH health database. Physical fitness indicators were evaluated based on the revised 2014 National Physical Fitness Standards for Students, and scores were assigned accordingly. An ordinal logistic regression (ologit) model was employed to analyze the relationship between body mass index (BMI) and physical fitness.

RESULTS

(1) Normal-weight boys achieved significantly higher physical fitness test scores than boys in other weight categories. (2) Underweight and normal-weight girls obtained significantly higher physical fitness test scores compared to overweight and obese girls, with underweight girls scoring slightly higher than those with a normal weight.

CONCLUSIONS

(1) There is a significant non-linear relationship between BMI levels and physical fitness test scores. (2) Gender differences were observed in physical fitness and overall health outcome. (3) The findings indicate an inverted U-shaped association between BMI and physical fitness among boys, while girls displayed an inverse relationship. This could be attributed to the cultural association between thinness and beauty among girls in China.

Association between BMI and health-related physical fitness: A cross-sectional study in Chinese high school students

Background

Existing studies reporting on the levels of physical fitness among high school students use relatively few fitness tests for indicators of physical fitness, thus, incomprehensively evaluating the levels of physical fitness. Therefore, this study investigated the relationship between body mass index (BMI) and physical fitness index (PFI) by investigating five physical fitness indicators and calculating PHI.

Method

Anthropometric measurements and indicators from five measures of physical fitness (50-m sprint, sit and reach, standing long jump, 800/1,000-m run, pull-up/bent-leg sit-up) were assessed. BMI was calculated to classify individuals into underweight, normal weight, overweight, and obese categories. Z-scores based on sex-specific mean and standard deviation were calculated, and the sum of Z-scores from the six fitness tests indicated the PFI. The findings were fitted to a linear regression model to elucidate the potential relationship between BMI and PFI.

Results

In total, 176,655 high school students (male: 88,243, female: 88,412, age: 17.1 ± 1.05 years, height: 168.87 ± 11.1 cm, weight: 62.54 ± 15.15 kg) in Jinan, China, completed the physical fitness tests between 2020 and 2021. The one-way ANOVA models showed that PFI in the normal category was significantly higher as compared to all the other BMI categories within both male and female groups (p < 0.001), and PFI in the obese category was significantly lower as compared to all the other BMI categories for both male and female groups (p < 0.001). The association between PFI and BMI showed an inverted U-shape relationship.

Conclusions

This study demonstrated that BMI affects the PFI in both males and females. As compared to the obese and overweight categories based on BMI, significantly higher scores of PFI were observed for males and females.