Research On The Characteristics Index Physical Activity Cyscly Regularity Of College Students With Time Series Complexity

Research purposes:(1)Design regular information collection and evaluation methods for periodic physical activity of college students based on the calculation principle of time series complexity;(2)Measured research on the relationship between physical activity complexity and body composition of college students a week.Research methods:(1)Re-encode the questionnaire code based on the Lempel-ziv complexity algorithm,so that it can be directly applied to the field of physical activity research,and use the improved Lempel-ziv complexity to complete the single-day physical activity time series.Evaluation.The weekly Lempel-ziv complexity is combined into a new time series,and the regularity of the periodic physical activity time series is evaluated from three aspects(average trend,variation level,and sudden level).Participants were recruited among freshmen from the first year to the third year of undergraduate studies at Beijing Sport University.The final survey object was 59(female n=35,male n=24).Bouchard’s physical activity record was used to conduct a weekly physical activity survey.The survey results were used to calculate the single-day physical activity Lempel-ziv complexity and regular indicators of periodic physical activity.The repeated measurement variance analysis and factor analysis were used to reduce the seven-day physical activity Lempel-ziv complexity to find the days with similar physical activity complexity within a week.In order to discuss the structural effectiveness of the design process,factor analysis was used to reduce the dimensionality of the six cycle regularity evaluation indicators and compare the consistency of the factor components with the design process.(2)Record the height and weight of the subject before physical activity for one week.,Waist circumference,hip circumference,body composition(body fat rate of DEXA test,calcaneus bone density),using correlation tests and stepwise regression analysis to explore the correlation and association points of college students’body composition,body circumference and physical activity indicators,At the same time,the feasibility of the physical fitness complexity evaluation index designed in the field of physical fitness is evaluated.Research results:(1)In this study,Bouchard’s physical activity records were used to measure the daily physical activity of the study subjects for seven consecutive days,and the results of the questionnaires were recorded in a database in a time series format and summarized.In order to discuss the continuity and change of physical activity,the sleep part in the sequence was eliminated,and the part of meditation and three kinds of intensity physical activity(SB,LPA,MPA,VPA)were retained to form a new binary physical activity time series.The binary LZC algorithm was used to calculate the complexity level of daily physical activity.The LZC level corresponds to the subject information and date,forming a new weekly time series of LZC changes in physical activity.The six aspects of the regularity of the physical activity time series(average trend,level of variation and suddenness)were evaluated with six indicators:average,standard deviation,coefficient of variation,mean value of sudden intensity,number of sudden intervals,and mean length of sudden intervals.The factor analysis results showed that the complexity of physical activity within a week for men and women can be divided into two parts,rest days and work days(variance ratio:male48.50%vs 32.62%;female 36.90%vs 36.84%).Except that the intensity and average of the burst interval are attributed to the same factor,the three regular evaluation aspects are basically consistent with the three types of factor components obtained from the dimensionality reduction of six indicators.(2)The correlation analysis results show that the height,weight,BMI,waist circumference,There were no significant correlations between the six indicators of hip circumference and the trend of physical activity changes(P>0.05);waist-hip ratio and the dispersion coefficient(r=-0.34,P<0.01)had a low degree of significant negative correlation;body fat rate was related to The standard deviation(r=-0.26,P<0.05)and the average intensity of the burst interval(r=-0.33,P<0.05)have a low degree of negative correlation;the calcaneus bone density Z value and the number of burst intervals(r=0.44),P<0.05)had a significant degree of positive correlation,and had a significant degree of positive correlation with the average intensity of the burst interval(r=0.39,P<0.05).The results of stepwise regression show that for the regression of BMI as the dependent variable,only the gender factor entered the regression equation as the independent variable(R~2=0.26).For waist-to-hip ratio,only the coefficient of variation(CV)entered the regression equation(R~2=0.11)as the independent variable.The coefficient of variation(CV)had a significant effect on waist-to-hip ratio(β=-0.35,Sdβ=-0.34).For body fat percentage,gender,and the average intensity of the burst interval entered the regression equation as independent variables(R~2=0.46).The average intensity(I)of the burst interval also had a low degree of negative impact on body fat percentage(β=-16.00).,Sdβ=-0.26).For the calcaneus bone mineral density Z value,the gender and the number of sudden intervals(Q)are used as independent variables to enter the regression equation(R~2=0.30).The number of sudden intervals(Q)also has a low degree of positive impact on the body bone density Z value.(β=0.494,Sdβ=0.38).Research conclusion:(1)Based on Lempel-ziv complexity,the design process for evaluating the regularity of periodic physical activity from three aspects:average trend,discrete level,and sudden level has good structural validity.(2)The"discrete level"in the three aspects of the evaluation process describes the general trend of the Lempel-ziv complexity in the period,and it has a significant correlation with the waist-hip ratio to a low degree.The"emergency level"describes the variation trend of extreme Lempel-ziv complexity during the period,and has a significant degree of low correlation with body composition(body fat rate,calcaneus bone density Z value).