Application Of Compositional Data Analysis Methods In Physical Fitness And Health

Purpose:To review the development and application of compositional data analysis,and to introduce its basic principles and methodology into the field of physical fitness and health,then to provide a visual analysis process of the method through one case study,which explored the combined effects of 24-hour movement behavior on physical fitness and the compositional isotemporal substitution effects between them among secondary school students.Methods:(1)Sorted out the methodological process of compositional data analysis;(2)In the case analysis:using a combination of convenience sampling and random cluster sampling,a valid sample of 241 junior high school students was obtained in Beijing and Shanxi.The participants’physical activity-related behaviors were measured by ActiGraph GT3X+accelerometer.And according to National Student Physical Fitness Standard,the physical fitness indicators were measured,including height,weight,vital capacity,50 m,sit and reach,long jump,sit-ups(for girl)/pull-ups(for boy)and 800 m(for girl)/1000 m(for boy),and they were scored and graded.Compositional data analysis was used for data processing,and to analyze the relationship between 24 h activity behaviors and physical fitness by compositional multiple regression model and their compositional isotemporal substitution effects using compositional isotemporal substitution model.All statistical analysis was performed using R 3.6.3.Results:(1)In the stratified analysis of physical fitness level,compared with the corresponding activity behavior time use of the total sample,among those with excellent physical fitness scores,the time of moderate-to vigorous-intensity physical activity(MVPA)and sleep(SLP)time were both 3%higher,while sedentary behaviour(SB)time was lower,but the amplitude was approximately zero,and low-intensity physical activity(LPA)time was 6.1%lower.(2)In the BMI groups,compared to the total sample,LPA in the overweight and obese was 6%higher,and MVPA time was 4.4%higher,as well as SLP time was 2.2%higher,while SB time was 4.8%lower.The behaviour combination pattern of the thin was opposite,showing that LPA,MVPA and SLP time were all lower than those of the total sample,while SB time was 2.5%higher.(3)The compositional multiple regression analysis showed that SLP and MVPA were positively correlated with total physical fitness score and long-distance running score,while SB and LPA were negatively related with the scores(P<0.05);MVPA was negatively correlated with 50 m running time and positively related with long jump,while LPA was positively correlated with 50 m running time and negatively related with long jump(P<0.05);SLP was positively associated with sit and reach,long jump,and sit-ups(P<0.01),while SB and LPA were generally negatively correlated with these indicators(P<0.05).(4)The dynamic diagram of compositional isotemporal substitution analysis showed that in the various physical fitness indicators,the effect differences between MVPA substituting other behaviors and MVPA being substituted were asymmetrical,for example,when SB replaced 10-minute of MVPA or SLP,it predicted that the total physical fitness score of adolescents would decreased 0.9 and 0.22 points respectively,and when MVPA reversely replaced SB,the total fitness score only increased by 0.73 points.This phenomenon also existed in other indicators,like 50 m running and long jump.And when MVPA time increased,the physical fitness score,50 m running performance,long jump performance and long-distance running score had a greater improvement,for instance,when MVPA or SLP replaced 10-minute of SB,the total score increased by 0.73 and 0.22 respectively,and 50 m running time decreased by 0.07 s and 0.01 s respectively,while long jump performance increased by 0.02 m and 0.006 m respectively,and the long-distance running score increased by 1.14 points and 0.34 points,respectively,which showed the substitution effects of MVPA was greater than that of SLP.(5)In the substitution of 5 min,10 min and 30 min,it has shown that MVPA replaced SB or LPA or SLP,the substitution effect on physical fitness measures were different.For example,in the substitution of 5 min,the 50-meter running time was reduced by 0.036 s,0.043 s,0.032s,respectively,which also existed in the total score of physical fitness and long-distance running score.Conclusion:(1)The proposed isometric log-ratio transformation makes it possible to analyze the compositional data,and contributes to the development of the compositional data analysis into a relatively complete statistical analysis method.And considering that there are compositional variables in the field of physical fitness and health research,the introduction of this method is an inevitable trend.(2)High MVPA/moderate SLP/low SB/moderate high LPA may be an important behavior combination intervention pattern for physical fitness promotion,and MVPA may be the main influence component of the promotion.MVPA is good for the improvement of the overall physical fitness,speed,strength and aerobic capacity,while LPA only has a positive effect on vital capacity.Meanwhile,sleep is also an indispensable intervention direction for physical fitness development;(3)From the results of substitution analysis,compared with simply reducing SB,the maintenance of MVPA levels may be more important for maintaining the physical fitness level and its development;(4)MVPA accumulation time of 40 min or more can have a beneficial effect on overall physical fitness,lower limb explosive power,aerobic capacity and speed.