OBJECTIVETo describe secular trends on physical growth of children in China during the year of 1985-2005 and to analyze the urban-suburban-rural difference and its change.

METHODSThe measurements of height, weight and chest circumference obtained from two serial national cross-sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared.

RESULTSThe average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban-suburban difference in height had become smaller, and that in weight showed similar trend for children under 3 years old but became larger after 3 years old; the suburban-rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group.

CONCLUSIONPositive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio-economic development in China.

Adolescent ; Adult ; Anthropometry ; Child ; Child, Preschool ; China ; Female ; Growth ; Humans ; Infant ; Male ; Rural Population ; Suburban Population ; Urban Population

Exercise is medicine.Exercise is not only the cornerstone of children′s normal growth and development, but also the necessary condition of physical and mental health.Moreover, exercise contributes to the management of childhood asthma.Exercise prescription is an effective method for children with asthma, but there is no much experience in China, we should continuously explore and optimize it.Therefore, the level of physical activity could be improved in children with asthma.

Objective: To analyze the impact of parental sports concept and behavior on physical activity in preschool children, so as to provide a foundation for future guidance on fostering childrens physical activity within the family context. Methods: From November to December 2020, a clustered convenience sampling method was employed to conduct surveys, and a total of 283 children were selectal from one kindergarten each in Beijing, Shenyang, and Xian. Participating children wore ActiGraph GT9X accelerometers continuously for one week to collect data on different intensity levels of physical activity. Physical Activity afterschool Questionnaire for Preschooler (P-PAQ) was utilized to assess parental sports concept and behavior. The gender differences in physical activity level and physical activity compliance rate were analyzed by using ttest, Mann-Whitney U test, and Chisquare test; and the relationship between parental exercise concepts and behaviors and physical activity of preschool children was analyzed using Spearman rank correlation analysis and multiple linear regression analysis. Results: Parental sports concept was significantly positively correlated with average daily moderatetovigorous physical activity (MVPA) and total physical activity (TPA) in children (r=0.12-0.16, P<0.05). Parental sports behavior was significantly positively correlated with childrens average daily TPA (r=0.25, P<0.05). Multiple linear regression revealed that parental sports concept was positively correlated with average daily MVPA and TPA in both boys and girls (B=0.65-0.83), while parental sports behavior only was positively correlated with boys average daily MVPA and TPA (B=0.24-0.25)(P<0.05). Conclusions Parental sports concept and behavior can impact physical activity levels in preschool children, exhibiting gender differences. Future guidance on physical activity in family upbringing should consider both parental sports concept and behavior, and pay attention to the influence of childrens gender.

Objective: To establish the norm of the Physical Activity afterschool Questionnaire for Preschooler(P-PAQ) in urban areas of China, so as to provide a basis for graded guidance from the family perspective and to improve children s physical activity levels. Methods: From October 2020 to January 2021, 6 267 children aged 3-6 years old were recruited from 40 kindergartens in eight cities across six major administrative regions by stratified cluster sampling, and the P-PAQ initially developed by the researchers of this study were completed by the primary caregivers. The questionnaire was administered to collect data relating to the amount of physical activity undertaken by the preschoolers, and the norm was determined by quartiles. Data relating to parental concepts of sports and parental behavior were assessed by calculating mean scores in order to establish the norm. Results: Among preschoolers in urban areas, the M(P 25 ，P 75 ) of total physical activity time (min/day), moderate-to-vigorous physical activity time (min/day), outdoor time (min/day) and screen time (min/day) on school days outside kindergarten and on weekends were 84 (54,120), 22 (8,40), 12 (0,24) and 18 (6,30), and 170 (115,240), 60 (30,95), 90 (35,120) and 30 (20,60), respectively. When the score of parents sports concept and behavior (total score of 40) were≥34, 29-<34, 24-<29, <24, it was defined as four levels about above medium, medium, lower medium and lower, respectively. And for two dimensions，when the score of parental sports concept were ≥19, 17-<19, 15-<17, <15，and the score of parental behaviors were ≥16, 12-<16, 8-<12, <8, it was defined as four levels about upper medium, medium, lower medium and lower, respectively. Conclusion The norm of extracurricular activities among preschool children in Chinese cities has good representativeness and appropriate threshold values, which could provide a valuable reference for early assessment, as well as guidance in relation to out-of-school physical activity behaviors among children aged 3-6 years old.