Explring The Relationship Between 24-Hour Movement Behavior And Adolescent Physical Fitness Based On CoDA Method

ObjectiveThe physical fitness of adolescents is related to the prosperity of the country and the rise and fall of the nation.The health level of adolescents in a country can provide a basis for predicting the future health status of the country’s adult population.The measures for the monitoring and evaluation of students’ physical fitness and the outline of healthy China 2030 plan recently issued by the Ministry of education clearly put forward that the health of children and adolescents is the cornerstone of national health and one of the important links in the implementation of the healthy China strategy.Research shows that in 2018,the overweight rate of Chinese children and adolescents was 9.6%,and the obesity rate was 6.4%,and the incidence of obesity still showed an increasing trend year by year.At present,the physical quality of young students in China,such as speed,strength and lower limb explosiveness,continues to decline,and the body shape indicators are also increasing.The phenomenon of obesity is becoming more and more serious,and the overall physical fitness is worrying.The 24-hour movement behaviors of children and adolescents,including physical activity(PA),sedentary behavior(SB)and sleep(SLP),are important factors affecting physical fitness.Researchers often ignore the relationship between behaviors and analyze the effect of an activity in isolation.The recently released physical activity guide for children and adolescents only focuses on moderate to vigorous intensity physical activity(MVPA)and sedentary behavior,and does not consider other activities related to health and obesity in children and adolescents.MVPA will only account for a small part of the 24 hours a day.In contrast,SB,SLP and light intensity physical activity(LPA)account for most of the 24 hours.Domestic studies have analyzed the situation of children’s 24-hour activity behavior and its relationship with BMI,but it is only limited to the aspect of body shape and lack of comprehensive research on physical fitness.In essence,24-hour time-use data is multivariate data with definite and binding(i.e.the sum of the ratio of each component is 1).The analysis using traditional multivariate statistical methods may lead to problems such as inconsistency with the reality,pseudo-correlation and difficult interpretation.Therefore,based on the method of compositional data analysis(CoDA),this study discusses the impact of adolescents’ 24-hour movement behaviors on physical fitness under the framework of time-use epidemiology,and deeply discusses the best time allocation scheme to improve adolescents’ physical fitness level.MethodThis study adopts a cross-sectional research design.749 students in the first grade of a middle school in Foshan(352 boys and 397 girls,aged 14-17 years)are taken as the research objects.The demographic characteristics、work and rest and other information of students are collected through the health behavior questionnaire.The 24-hour movement behavior and physical fitness items of students are measured by triaxial accelerometer and instruments required for physical health monitoring.In this study,CoDA method was used to analyze the proportion distribution of 24-hour time-use components of adolescents,and the ternary diagram was used for visualization.The calculation of variation matrix reflects the interdependence between components.Univariate CoDA regression model and multivariate CoDA regression model were used to analyze the relationship between adolescents 24-hour movement behavior and physical fitness based on isometric logratio transformation(ilr).Based on the compositional isochronous substitution model,this paper explores the changes in the total score of physical fitness caused by the mutual substitution of MVPA and other activities and behaviors at different durations.Finally,the isochronous substitution effect diagram was used to analyze the changes in the total score of physical fitness caused by the mutual substitution of MVPA and other activity behaviors at different allocated times(from 0 minutes to 50 minutes,with an interval of 5 minutes).ResultThe study included 694 students,309 boys and 385 girls.Students aged 14-15 and 16-17 accounted for 72.33%and 27.67%respectively.1.Physical fitness of status of adolescents:the results showed that the overall physical fitness level of the first grade in senior high school presents an excellent level.The mean values of BMI,vital capacity and standing long jump of boys are higher than those of girls,and the mean values of 50-meters running and sitting forward flexion of girls are higher than those of boys.There were significant differences in BMI,50-meters running,standing long jump and sitting forward flexion between men and women.The average scores of male students in 50-meters running,sitting forward flexion and 1000/800 meters running were higher than those of female students,while the average scores of female students in BMI,vital capacity,standing long jump and sit-up/pull-up were higher than those of male students.There were significant differences in vital capacity,standing long jump and sitting forward flexion between male and female students.Girls’ body shape,physical quality and physical function scores are higher than boys,but the total score is lower than boys.There is only statistical difference between boys and girls in physical function scores.2.24-hour time-use of adolecents:the daily MVPA and LPA time of adolescents’ study days are higher than that of weekends(MVPA:55.58 minutes vs.35.71 minutes;LPA:239.18 minutes vs.211.68 minutes),and the SB and SLP time of study days are lower than that of weekends(SB:681.55 minutes vs.717.41 minutes;SLP:463.68 minutes vs.475.34 minutes).In the study day,the geometric mean of SLP,MVPA and LPA of boys were higher than that of girls(SLP:471.89 minutes vs.455.04 minutes;MVPA:80.06 minutes vs.41.33 minutes;LPA:241.49 minutes vs.236.16 minutes),while the geometric mean of sedentary behavior of girls was higher than that of boys(SB:707.41 minutes vs.646.70 minutes).On weekends,only MVPA of boys is higher than that of girls,and other activities are lower than that of girls(MVPA:49.10 minutes vs.27.50 minutes;LPA:206.50 minutes vs.215.42 minutes;SB:711.94 minutes vs.720.29 minutes;SLP:472.32 minutes vs.476.78 minutes).Regardless of boys and girls,SLP has a strong correlation with LPA and SB,while MVPA has a weak correlation with the other three times ratios.3.Physical fitness of adolescent of CoDA regression model:MVPA of the general population is positively correlated with standing long jump compared with other activities(one week:βMVPA=14.5,P<0.01;school day:βMVPA=14.85,P<0.01;weekend:βMVPA=4.96,P=0.02);MVPA was negatively correlated with 50-meters running relative to other activities(one week:βMVPA=-0.29,P<0.01;study day:βMVPA=--0.30,P<0.01;weekend:βMVPA=-0.11,P=0.05),but the component model showed no statistical significance;LPA was positively correlated with sitting forward flexion relative to other activities(one week:βLPA=2.46,P=0.05;weekend:βLPA=3.3,P<0.01).Compared with other activities,boys’ MVPA was positively correlated with sitting forward flexion(one week:βMVPA=5.23,P<0.01;study day:βMVPA=5.34,P<0.01),and LPA was negatively correlated with sitting forward flexion compared with other activities(School days:βLPA=-3.70,P=0.04),but the component models showed no statistical significance.The results of the regression model of multivariate component data for girls have not found a statistically significant relationship between the distribution of 24-hour activity behavior and physical health.4.Physical fitness score of adolescent of CoDA regression model:the results of single factor coda regression model of the total population show that SB is negatively correlated with other activity behaviors and body shape scores(one week:βSB=-1.83,P<0.01;School day:βSB=-1.21,P=0.02;weekend:βSB=-1.12,P<0.01);SLP was positively correlated with other activity behaviors and body shape scores(one week:βSLP=2.11,P<0.01;School day:βSLP=1.45,P=0.04;weekend:βSLP=0.84,P=0.03)。Male students’ MVPA in one week is positively correlated with other activity behaviors and physical fitness scores(βMVPA=2.48,P=0.03);SB relative to other activities was negatively correlated with body shape score(one week:βSB=-2.39,P=0.01;weekend:βMVPA=-1.36,P=0.01);LPA of female students is positively correlated with other activity behaviors and body shape(one week:βLPA=0.80,P=0.04;Study day:βLPA=0.84,P=0.02);LPA on school day was positively correlated with other activity behaviors and the total score(βLPA=1.93,P=0.05)。The results of multivariate CoDA regression model of the total population showed that SB was negatively correlated with other activity behaviors and body shape scores(one week:βSB=-1.87,P<0.01;βSB=-1.23,P<0.01;weekend:βSB=-1.16,P<0.01);SLP was positively correlated with other activity behaviors and body shape scores(one week:βSLP=2.30,P<0.01;Study day:βSLP=1.59,P=0.03;weekend:βSLP=0.95,P=0.01)。Male MVPA was positively correlated with physical fitness(one week:βMPA=2.65,P=0.02;Study day:βMVPA=2.44,P=0.04)。SB relative to other activities was negatively correlated with body shape score(one week:βSB=-2.37,P<0.01;weekend:βSB=-1.47,P0.01);SLP was positively correlated with other activity behaviors and body shape scores(one week:βSLP=3.41,P<0.01;Study day:βSLP=2.47,P=0.02;weekend:βSLP=1.27,P=0.05)。Compared with other activities,LPA of girls on school day was positively correlated with body shape score(βLPA=0.81,P=0.03),which was positively correlated with the total score of physical health(βLPA=2.09,P=0.04);Weekend SB relative to other activities was negatively correlated with body shape score(βSB=-0.89,P=0.05)。5.Isotemporal substitution model of adolescent physical fitness:MVPA isochronous substitution for other activities causes the total score of physical fitness to increase,and vice versa.With the increase of the time for MVPA to replace LPA,Sb and SLP,the total score of physical fitness is gradually increasing,and the increase range is MVPA to replace SB,MVPA to replace SLP,MVPA to replace LPA.Conclusion:1.The passing rate of adolescents’ physical fitness is high.There are statistically significant differences in BMI,50-meters running,standing long jump and sitting forward flexion between boys and girls.2.The time of MVPA and LPA was higher than that on weekends,and the time of SB and SLP was lower than that on weekends.MVPA time is obviously insufficient for girls.SLP has a strong time proportion correlation with LPA and SB,and MVPA has a weak time proportion correlation with the other three items.3.Compared with other activities,MVPA was positively correlated with standing long jump,and MVPA was negatively correlated with 50-meter running compared with other activities;LPA was positively correlated with sitting forward flexion compared with other activities.In the total population,SB was negatively correlated with other activity behaviors and body shape scores;SLP was positively correlated with body shape scores compared with other movement behaviors.Male MVP A was positively correlated with physical fitness.SB was negatively correlated with other activity behaviors and body shape scores;SLP was positively correlated with body shape scores compared with other movement behaviors.Girls’ school day LPA was positively correlated with other movement behaviors and physical fitness total score.4.When MVPA replaces other activities,the total score of physical fitness increases,and vice versa.