A009: Volume, Accumulation Patterns of Sedentary Behavior and PhysicalFitness Among Elementary School Students

Objective: The increase in sedentary behavior in children has become a worldwide public health problem. This study aimed to explore the associations of volume and accumulation patterns of sedentary behavior with physical fitness among elementary school students. Methods: A cluster sampling method was used to select students from grades 1–5 in Jinhua, Zhejiang province. Accelerometers were used to assess sedentary volume, duration of sedentary bouts (1-4 minutes, 5-9 minutes, 10-19 minutes and ≥20 minutes), and duration of sedentary breaks (1-4 minutes, 5-9 minutes and ≥10 minutes). The scores and good-excellent rate of physical fitness were calculated according to the "National Student Physical Health Standards (Revised in 2014)". Binary logistic regression was used to examine the relationship between volume, accumulation patterns of sedentary behavior and students' physical fitness. Results: A total of 307 participants (mean age 8.5 years) were included in the statistical analysis. The score and the rate of good-excellent of physical fitness were 78.1 and 38.5%. The students spent 139.5min (64.9%) in the classroom time. The highest proportions of sedentary bouts of 1-19 minutes (46.7%) and breaks of 1-4 minutes (17.2%) indicate a fragmented and intermittent characteristic in the classroom. There were significant sex and grade differences in sedentary behavior accumulation patterns. Boys were more active than girls in the classroom, while second graders were the most active and fifth graders accumulated the most sedentary time. After adjusting for covariates, sedentary bouts of 5-9 minutes were a protective factor for physical health (odds ratio (OR)=3.118; 95%CI:1.271, 7.649), and the OR was 28.1% higher for each percentage point increase. The sedentary bout of ≥20 minutes was a risk factor for physical health (OR=0.430; 95%CI:0.223, 0.827), and the OR of not good-excellent physical fitness standard was 23.1% lower for every one percentage point increase. There was no significant correlations between the sedentary volume, the duration of the sedentary break, and physical health (P＞0.05). Conclusion: Reducing the duration of sedentary bouts in the classroom may be more important for health of children than reducing total sedentary time. It is recommended to consider the teaching mode and the physical and mental characteristics of elementary school students, and reasonable interruptions should be made in classrooms. Teachers can interrupt prolonged sitting every 10 minutes with varying duration of breaks, to avoid students sitting for more than 20 minutes during class time. School-based interventions are needed to verify the findings of this study.