Study And Analysis On The Middle School And High School Students’ Physical Activity By Accelerometer

Objective: To obtain objective data of middle and high schoolstudents’ physical activity and sedentary behavior by accelerationsensors, to know of students’ health-related physical fitness byfitness testing, and to analysis the relationship between physicalactivity and health-related physical fitness, to investigate thefactors that influence physical activity through a questionnaire.In order to increase physical activity of middle school students,and to provide some scientific basis of health-related physicalfitness.Method: Select two schools in Nantong City, Jiangsu Province, JinjiaoJunior High school and Tongzhou Senior High School. Use the methodof random stratified cluster sampling, select each of two classesof students as an object of study from junior1、junior3and senior2, there is a total of286people, aged11.7-17.8years old. Studentsshould wear Actigraph GT3X acceleration sensor for a week (includingSaturday and Sunday)to obtain average activity intensity (AI), thetime of physical activity (MVPA) and sedentary behavior. Do thefitness test by the National Student Physical Health Standard andthe content of Fitnessgram youth physical health test establishedby Cooper Aerobic Institute. Using the students’ daily habitsquestionnaire to investigate the factors that affect physicalactivity. Using EXCEL to entry and finishing the data, using JMP10 to census and analysis the data.Results:1. The effective wear time is7.0±1.0days, the average daily weartime is14.5±1.2hours. Girls of junior1have the shortest dailywear time, it’s11.3hours/day, the girls of senior2have thelongest daily wear time, it’s16.1±0.5hours/day, that ensure thevalidity of the data.2. The AI is268.1±90.2counts/min, the girls’ level of each gradeis lower than boys (P<0.0001), the senior2students’ level is thehighest; MVPA is38.4±19.0minutes/day, the boys’ time of each gradeis more than girls’(P<0.0001);there are only42students(15%)meeting the recommended activity level, among senior2boys, the people who meet the level are more than those who didnot meet, there’s no one of the girls in junior1and junior3meetingthe recommended activity level; their time of daily average sedentarybehavior was10.9hours (sleep time excluded), accounting for75%of the total time, the boys wear10.4hours a day, accounting for72.4%of the total time, the girls wear11.3hours, accounting for77.3%. Each grade girls’ time of sedentary behavior is longer thanboys’(p<0.0001). The higher grade has more time of sedentarybehavior. AI has no statistically significant difference betweenworkday and weekend, MVPA, sedentary behavior time and sedentary behavior accounted the more percentage of effective wear time,different grades have different results and different genders havethe same result.3.The students who participate in the sports teams have more AI andMVPA than those who did not participate in the sports teams, but lesstime of sedentary behavior (P<0.05);the students who are good atsports have less sedentary behavior, junior1boys who are good atsport have more AI and MVPA,but less sedentary behavior time;students who walk or ride bicycle have more AI and longer MVPA,butshorter sedentary behavior time; junior1girls and junior3boyswho are in the group of heavy course load have more sedentary behaviorthan general group(P<0.05),students who do homework less than2hourshave more AI,but less sedentary behavior time（P<0.05）;studentswho have sport equipment at home have longer MVAP, but shortersedentary behavior time（P<0.05）.4. In the relationship between physical activity and health-relatedfitness, there’s no statistically difference among normal weight,overweight and obese students’ AI, MVPA, and sedentary behavior,at the same time, students who did not meet the recommended activitystandards have no difference with who meet the standard in WHR and“sit and reach” test, late adolescence boys’ who meet the standardof new “sit and reach” test are better than the students who didn’tmeet the standard (P <0.01); among mid-adolescence boys, the group who meet the physical activity standards have larger grip and highervertical jump, among late adolescence boys and girls, the group whomeet the physical activity standards have larger grip; the studentswhose lung capacity is stronger have less MVAP and shorter sedentarybehavior time, and their heart rate are lower(P<0.05),but SBP andDBP are higher.Conclusions：1.The AI of students in Nantong City, Jiangsu Province is low, MVPAis38.4min/day, it’s less than international recommended activitylevels of60minutes a day, there’s only15%of students reach theinternationally recommended activity, sedentary behavior timeis10.9hours/days. Boys have large amount of physical activity, girlshave longer sedentary behavior time, students’ physical activityhas different characteristics between weekday and weekend.2.Gender, grade, weekday and weekend, sports skill, self-efficacy,modes of transportation, learning factors, family factors and otherfactors can influence students’ physical activity level.3.Participating in school sports teams and sports self-efficacy willaffect students’ physical activity level. Reasonable transportationcan increase the level of physical activity and reduce sedentarybehavior. Homework time will directly affect the sedentary activitytime and maybe the factor reduce the AI. Parents’ support is not the main factor that affect the level of physical activity and sportsequipment will affect middle school students participating inphysical activity.4.Full amount of MVPA can make the body generate adaptive heart rateslow. And it can enhance students’ flexibility and the strengthquality at the appropriate stage of pubertal development.