Establishment Of The Maximum Oxygen Uptake Equation For Primary School Children Based On The 6-minute Walking Tes

Objective:Cardiopulmonary endurance is a key reference index to judge whether children are physically and mentally healthy,is the core element of physical health,has a core role in children’s physical and mental health development,to improve the level of cardiopulmonary endurance has become an urgent task to promote the healthy development of Chinese children.To improve the level of children’s cardiopulmonary endurance has become an urgent research topic to promote the healthy development of Chinese children.In this study,part of the physical indicators of primary school children were collected,and the direct measurement of maximal oxygen uptake and the 6-minute walking test were carried out.Considering the influencing factors of maximal oxygen uptake,the relevant physical shape indicators,cardiopulmonary function indicators and the related indicators of 6-minute walking test were screened out through statistical analysis.To establish a prediction equation of the maximum oxygen uptake of primary school children in the 6-minute walking test,and to provide an indirect method for the determination of cardiopulmonary endurance level of primary school children.Methods:In this study,154 healthy children（77 males and 77 females）were randomly recruited to measure the body shape index and cardiopulmonary function index of the subjects.The 6-minute walking test and direct measurement method of maximal oxygen uptake were carried out to measure the absolute and relative values of maximal oxygen uptake,maximum heart rate and maximum respiratory quotient.SPSS 26.0 was used for data processing:The absolute value and relative value of maximal oxygen intake measured by direct method were analyzed by Pearson correlation analysis with height,body weight,BMI,vital capacity,quiet heart rate,waist circumference,chest circumference,hip circumference,waist-to-hip ratio,waist-to-height ratio,6-minute walking distance（6MWD）and immediate heart rate at the end of 6-minute walking test（6MWT）.Body shape indexes,cardiopulmonary function indexes and 6-minute walking test results that are highly correlated with VO₂max and VO₂max/kg were selected for multiple linear regression,so as to establish regression equations for absolute value of maximal oxygen uptake（VO₂max）and relative value of maximal oxygen uptake（VO₂max/kg）of primary and young children.Reliability and validity were tested by variance analysis test,goodness of fit test,VIF test,Durbin-Watson test and back substitution test.Results:1.In this study,age,height,weight,BMI,vital capacity,chest circumference,waist circumference,hip circumference,6MWD and 6MWT immediate heart rate were positively correlated with VO₂max（L/min）,while quiet heart rate,waist-hip ratio and waist-height ratio were not significantly correlated with VO₂max（L/min）.2.Based on the 6-minute walking experiment established in this study,the VO₂max equation of elementary school children was deduced as follows:VO₂max（L/min）=-0.147174+0.027458×X₁+0.001801×X₂+0.000138×X₃-0.010558×X₄;X₁:body weight;X₂:6MWD;X₃:vital capacity;X₄:hip circumference;The goodness of fit test R²=0.762,R²adj=0.755,SEE=0.156（L/min）,and the significance of the equation p<0.001.3.The VO₂max absolute value equation established in this study was tested by variance analysis,and the significance of the equation was p<0.05.There is no multicollinearity in the equation,and the VIF of all independent variables is less than10.The established VO₂max equations satisfy normal distribution and are independent of each other.Back test results showed that the correlation between VO₂max measured by direct method and VO₂max calculated by equation was 0.879,and there was no significant difference between the two groups.Conclusion:1.Based on body weight,6-minute walking distance,vital capacity and hip circumference,the calculation equation of maximal oxygen uptake in primary school children was established:VO₂max（L/min）=-0.147174+0.027458×X₁+0.001801×X₂+0.000138×X₃-0.010558×X₄;X₁:body weight;X₂:6MWD;X₃:vital capacity;X₄:hip circumference;Goodness of fit test R²=0.762,revised R²=0.755,SEE=0.156ml/beat,p<0.001 of the equation.2.After variance analysis test,goodness of fit test,Durbin-Watson test,etc,the calculated equation of maximum oxygen uptake established in this study has good goodness of fit and reliability.3.Back test showed that the established equation had good validity,and there was no significant difference between the measured and predicted maximum oxygen uptake values,and the correlation reached 0.879.4.In this study,body weight,6-minute walking distance,vital capacity and hip circumference were adopted to establish the calculation equation of maximal oxygen uptake of primary and young children.