| Objective: In 2016,Canada issued 24-hour movement guidelines,which made recommendations on children’s moderate-to-vigorous physical activity(MVPA),screen time(ST)and sleep.However,existing studies show that children’s adherence with the activity guide is very low.24-hour movement is an important factor in children’s physical fitness.Developing good behavior habits in childhood will have a profound impact on adulthood.At present,the influence of adherence of 24-hour movement guidelines on children’s physical fitness at home and abroad is mainly cross-sectional,and there are differences in physical fitness indicators at home and abroad.In the longitudinal study,only the relationship between physical activity,sedentary behavior and physical fitness is concerned,sleep is ignored.Therefore,the purpose of this study is to analyze the cross-sectional relationship between the adherence of 24-hour activity guidelines in the first year and the physical fitness status,and the longitudinal relationship between the physical fitness status in two consecutive years,so as to provide new ideas for the long-term promotion of children’s physical fitness from the perspective of 24-hour activities.Methods: Total 450 children aged 6-10 were recruited from a primary school randomly selected from two urban districts(Haidian District and Dongcheng District)and two suburban districts(Yanqing District and Shunyi District)in Beijing.The basic information and 24-hour movement behaviors including MVPA,ST and sleep were obtained by questionnaire survey.The adherence of the guidelines was analyzed according to whether the subjects reached "MVPA≥60min/d,ST≤2h/d,sleep time is between 9-11h/d".According to the National Students’ physical fitenss standard,the physical fitenss status of the subjects was measured for two consecutive years,including height,weight,BMI,lung,sit-and-reach,50 m running,1 min rope skipping and 1 min sit-up.Then calculated the score of physical fitness.Paired Samples t-Test was used to compare the physical fitness of the subjects for two consecutive years.Two-factor analysis of variance was used to explore the cross-sectional relationship between the adherence of 24-hour movement guidelines and physical fitness of the subjects.Generalized estimation equation was used to analyze the longitudinal effect of baseline 24-hour movement guidelines adherence on two consecutive years physical fitness of the subjects.Results: 390 subjects provided valid data of 24-hour movement behavior.The baseline daily MVPA time was 88.35±67.26 min,ST was 41.31±52.97 min,and sleep time was 8.91±0.62 h.Among them,60.82% reached MVPA guidelines,92.84% reached ST guidelines,56.25% reached sleep guidelines,and only 33.51% reached three guidelines at the same time.341 subjects provided physical fitness test data for two consecutive years.The height(137.84±8.22 cm vs.131.38±7.70 cm),weight(34.60±10.61 kg vs.30.54± 8.85 kg),BMI(17.92±3.93 kg/m~2 vs.17.44±3.56 kg/m~2),lung(1845.91±447.95 ml vs.1640.62±471.78 ml)and rope skipping(108.94±35.77 pcs/min vs.96.66±31.57 pcs/min)of the subjects in the second year were significantly higher than those in the first year and 50 m running time(9.99±1.15 s vs.10.31±0.97 s)was significantly lower than that in the first year(all p<0.05),but the physical health score(82.78±8.88 points vs.84.34±7.49 points)was significantly lower than that in the first year(all p<0.05).Cross section analysis showed that the rope skipping scores of the subjects who reached the three guidelines at the same time(102.00 pcs/min vs.93.64 pcs/min)were significantly higher than those who did not reach the three guidelines at the same time(p<0.05);the physical fitness scores of the subjects who reached the MVPA and MVPA+ ST guidelines(84.97 points vs.83.27 points;85.05 points vs.83.35 points)were significantly higher than those who did not(all p<0.05).Longitudinal analysis showed that the average number of rope skipping in two consecutive years(108.75 pcs/min vs.99.48 pcs/min)of the subjects who reached the three guidelines at the same time was significantly higher than that of the subjects who did not reach the guidelines(p<0.05).The subjects who reached the two guidelines at the same time had sit-and-reach(11.04 cm vs.9.25 cm)and sit-up(35.33 pcs/min vs.31.67 pcs/min)were significantly higher than those of children who only reached 1 or 0 guidelines(all p<0.05).The average score of physical fitness of the subjects who reached the three guidelines at baseline for two consecutive years(84.95 points vs.83.15 points)was significantly higher than that of the subjects who did not reach the three guidelines at the same time(p<0.05).Conclusion: The adherence of 24-hour movement guidelines is not high,and the score of physical fitness shows a downward trend,the situation is not optimistic.The cardiopulmonary endurance and lower limb muscle endurance of the subjects who reached the three activity guidelines were significantly higher than those who did not reach the three activity guidelines at the same time,and reaching the 24-hour activity guides had a positive impact on the overall development of cardiopulmonary endurance,lower limb muscle endurance and physical fitness of the subjects after one year of follow-up. |
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