Study On Correlation Between Sedentary Behavior,screen Time And Physical Fitness Of Chinese Children And Adolescents

ObjectsSedentary behavior and screen time are important factors affecting the physical fitness of children and adolescents,and excessive sedentary behavior and screen time have negative effects on the growth of children and adolescents.With the worldwide economic and living standards development,the lifestyles have changed dramatically,and the popularity of electronic products has increased,the children and adolescents' sedentary behavior raised,as the lack of physical activity has become widespread.This resulting in the continuous decline of children and adolescents' physical fitness draw public attention in various countries.Based on scientific theories and research practices,this study calculates the physical fitness index of children and adolescents to analyze the effects of sedentary behavior and screen time on physical fitness index and several physical fitness indicators.The dose-effect relationship between sedentary behavior and screen time and physical fitness provides theoretical basis for improving the physical fitness of Chinese children and adolescents.MethodsAccording to principle of random sampling,this study chose 7-18 year-old children and adolescents from 7 capital citys(Shanghai,Taiyuan,Wulumuqi,Changsha,Guangzhou,Chendu and Kunming)between 2018.9 to 2018.12.Approximately 30 boys and 30 girls of each age were selected from the primary school to senior high school students,and a total of 4264 participants were contained as the research objects.The t-test to construct the characteristics of children and adolescents' sedentary behavior,screen time and physical fitness distribution;and Z-score method was used to calculate the physical fitness index status of children and adolescents;and the doseeffect relationship between sedentary behavior,screen time and physical fitness was explored by logistic regression method.Results(1)The average sedentary behavior time of boys was 478.4minutes / day,and the average screen time was 68.9 minutes / day,while average sedentary behavior time of girls was 476.1 minutes / day,and the average screen time was 65.1 minutes / day.(2)Physical fitness has negative correlation with sedentary behavior.Boys with low sedentary behavior time had higher PFI than those high sedentary behavior time group in primary school and high school,and they had higher detection rates of high PFI,strength,agility and speed than those high sedentary behavior time,for 1.167 times and 1.242 times,1.042 times and 1.43 times,respectively.The PFI value of girls in the all three Key Stage from the low sedentary behavior group was higher than high sedentary behavior group.Compare with high sedentary behavior group,the girls from the low sedentary behavior group had better detection rate of high level PFI,cardiorespiratory fitness,abdominal strength,lower limb strength,flexibility,and speed,as the rates were 1.240 times,1.083 times,1.131 times,1.006 times,1.229 times and 1.404 times,respectively.(3)Physical fitness has negative correlation with screen time.Among three different screen time groups,boys with low screen time group had the highest PFI value,which were 0.10,0.22,and 0.36,respectively.Compare with those screen time more than 2 hours,boys with screen time less than 1 hour had high detection rates of high level cardiorespiratory fitness,strength,and agility for 1.300 times,1.146 times,and 1.893 times,respectively.As the same,the girls with low screen time group had the highest PFI value,which were 0.19,0.35,and 0.04,respectively.Girls with low screen time showed detection rates of high level PFI,cardiorespiratory fitness,strength,agility,flexibility,and healthy BMI zone were 1.663 times,1.059 times,1.318 times,1.037 times,1.130 times,and 1.354 times than high screen time group,respectively.Conclusions(1)Sedentary behavior has negative impact on physical fitness of Chinese children and adolescents.Low sedentary behavior is a protective factor for high level physical fitness detection rate.Sedentary behavior lower than 8 hours per day benefit to high level physical fitness detection rate.(2)Screen time also has negative impact on the physical fitness of Chinese children and adolescents.More screen time decrease the detection rate of high physical fitness index value detection rate.Screen time lower than one hour per day benefit to high level physical fitness detection rate.