Objective: To investigate the independent and joint associations of physical activity and sedentary behavior with 20 m shuttle run test (20 m SRT) performance among children. Methods: Using cluster random sampling method, a total of 1 144 children aged 6-12 years from 1 urban primary school in Guangzhou were selected and completed the questionnaire survey, physical examination, and 20 m SRT. Physical activity and sedentary behavior were collected through questionnaire. Poor performance on 20 m SRT run test was defined as standard Z score ≤0, which was calculated according to gender, age-specific mean and standard deviation. Based on moderate-to-vigorous physical activity (MVPA) (≥60 min/d, 30-<60 min/d, or <30 min/d) and sedentary behavior levels (cut-off point: the gender, age-specific 50th percentile value), all participants were divided into six subgroups. Multiple linear regression and Logistic regression were used to analyze the independent and joint associations of physical activity and sedentary behavior with 20 m SRT performance, respectively. Results: Low level of physical activity (β=-2.99, P<0.05) and high sedentary behavior (β=-1.75, P<0.05) were independently correlated with lower 20 m SRT performance. Compared with the reference group (MVPA≥60 min/d and low sedentary behavior), the risk for low performance on 20 m SRT was higher in those with MVPA<30 min/d, or those with high sedentary behavior. The risk for poor performance on 20 m SRT was gradually elevated with decreased physical activity levels in combination with higher level of sedentary behavior(P<0.05). Conclusion Physical activity and sedentary behavior were independently related to 20 m SRT performance among children. There is a clear does-response association, with elevated risks for poor performance on 20 m SRT with decreased physical activity levels in combination with higher level of sedentary behavior.

Objective: To investigate the different patterns of 24-h movement behaviors, and their associations with sociodemographic factors in a nationally representative sample of Chinese children aged 6-13 years. Methods: This study was based on a national multi-centered cluster intervention study involving 31 362 children aged 6-13 years from 7 provinces in China. Questionnaires were used to collect moderate to vigorous physical activity (MVPA), screen time (ST) and sleep duration, as well as sociodemographic variables including age, gender, area of residence, parents’ education level and family income. Generalized linear mixed model (GLMM) analyses were conducted for the 24-hour movement behaviors according to sociodemographic variables. Results: The proportions of individuals meeting the MVPA, ST, and sleep guidelines were 32.2%, 78.5%, 30.1%, respectively. The proportion that meet 0, 1, 2 and 3 recommended items was 9.6%, 47.7%, 35.0% and 7.7%, respectively. Age, gender, parents’ education levels and family income showed associations with PA, ST and sleep. Compared with low parents’ education group, the risk for unhealthy behavioral patterns was lower in those with high parents’ education level(P<0.05). Conclusion The current status of 24-hour physical activity for children aged 6-13 in China is not ideal, and social demographics should be considered when designing targeted interventions to promote children’s health.