A national survey of physical activity and sedentary behavior of Chinese city children and youth using accelerometers

The role of fundamental movement skills on children's physical activity during different segments of the school day

BACKGROUND

Although prior studies have demonstrated that children with high levels of fundamental movement skill (FMS) are more active throughout the day, little is known about children's FMS and their physical activity (PA) during different segments of the school day (e.g., recess, lunch break, and physical education). The present study focused on FMS and moderate-to-vigorous PA (MVPA) during school day and identifies the association between children's FMS and MVPA during different segments of the school day in China.

METHODS

A total of 322 children (boys n = 163, girls n = 159; Mage = 8.12, SD = 1.22 years) from four elementary schools involved in this study. Children's FMS and MVPA were measured using the Test of Gross Motor Development-2nd edition (TGMD-2) and hip-mounted accelerometers. Data such as height, weight, and socio-economic status (SES) were also obtained. Multilevel mixed regression models were used to examine the cross-sectional associations between FMS and MVPA. Models were adjusted for gender, age, standardized body mass index, and SES.

RESULTS

Children engaged in 32.19 min of MVPA during the whole school day. Boys were more active than girls and had higher object-control skills competency. Locomotor skills were positively associated with children's long recess (B = 1.063) and short recess time (B = 1.502) MVPA. Object-control skills were positively correlated with children's MVPA time during long recess (B = 1.244) and physical education (PE) lessons (B = 1.171).

CONCLUSION

The findings highlight the importance of developing both locomotor and object-control skills in elementary schools to lead more MVPA engagement during different segments of the school day.

Reasons and promotion strategies of physical activity constraints in obese/overweight children and adolescents

To explore the reasons for low levels of physical activity in obese/overweight children and adolescents and to propose appropriate strategies to promote their physical activity (PA). This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines by searching and analyzing the literature of studies related to physical activity in obese/overweight children and adolescents published between January 2003 and January 2023 in Web of Science, Scopus, and PubMed databases. A total of 31 relevant studies were included for analysis, of which 16 were quantitative and 15 qualitative. According to these studies, the PA of obese/overweight children and adolescents is mainly constrained by negative factors: Individual, interpersonal, and environmental. Among these factors, low levels of individual motivation and psychological sensitivity and vulnerability, lack of family support, negative social feedback, insufficient protection from government policies, and inadequate support from the built environment are the main reasons that constrain their PA. The promotion of PA in obese/overweight children and adolescents, who are subject to more constraints at all levels, requires a system of security that involves the government, the community, the school, and the family to address the problems they encounter and enhance the sustainability of engagement in PA.

Ecological correlates of sport and exercise participation among Thai adolescents: A hierarchical examination of a cross-sectional population survey

BACKGROUND

Understanding factors influencing adolescents' sport/exercise participation (S/EP) is vital to developing effective interventions, but currently, evidence from less developed countries is limited. The purpose of this study was to examine correlates of S/EP across individual, interpersonal, and environmental levels in a nationally representative sample of Thai adolescents.

METHODS

Data from 4617 Thai adolescents aged 14-17 years old were obtained from recruited schools across Thailand. Data on S/EP (outcome variable), and psychosocial, home, and community environment covariates were collected from individual adolescents using the Thailand Physical Activity Children Survey, Student Questionnaire. School environmental data were collected at the school level using a School Built Environment Audit. Hierarchical regressions taking into account school clustering effects were applied for data analysis.

RESULTS

At the individual level, age and body mass index were independently and strongly correlated with S/EP. Adolescents with high preference for physical activity (PA) (odd ratio (OR) = 1.71, p < 0.001) and at least a moderate level of self-efficacy (OR = 1.33, p = 0.001) were more likely to have high S/EP. At the interpersonal level, adolescents whose parents joined their sports/exercise at least 1-2 times/week (OR = 1.36, p = 0.003) received ≥3 types of parental support (OR = 1.43, p = 0.005) and who received siblings' (OR = 1.26, p = 0.004) and friends' (OR = 1.99, p < 0.001) support had a greater chance of high S/EP. At the environmental level, adolescents' S/EP was greater when there were at least 3-4 pieces of home sport/exercise equipment (OR = 2.77, p = 0.003), grass areas at school (OR = 1.56, p < 0.001), and at least 1-2 PA facilities in the community (OR = 1.30, p = 0.009).

CONCLUSION

Multiple factors at different levels within an ecological framework influencing Thai adolescents' S/EP were generally similar to those found in developed countries, despite some differences. For those interested in promoting and supporting Thai adolescents' engagement in sports/exercise, further exploration of the influence of self-efficacy and attitude toward PA is required at the individual level; parental and peer support at the interpersonal level; and home sport equipment, school grass areas, and neighborhood PA facilities at the environment level.

Parental support for physical activity and children's physical activities: a cross-sectional study

BACKGROUND

Physical activity (PA) in school-aged children is imperative for physical and mental development. However, there has been reduced PA among children in recent years owing to environmental changes, resulting in declining physical strength and athletic ability. Although parents' and children's PA has been found to be correlated, the specific parental caregiving attitudes associated with children's actual levels of PA during school-age years remain unknown. Therefore, this study aimed to examine the relationship between parental support for PA and children's levels of PA.

METHODS

In 2017, a self-reported questionnaire survey was administered to 1,515 third-grade students (8-9 years old) and their caregivers in Nagoya, Aichi, a major metropolitan area in Japan. The main items surveyed included the attitudes of children and parents towards PA and the children's actual PA level. Multiple regression analysis was conducted with parental involvement related to PA as the explanatory variable and children's PA as the objective variable.

RESULTS

In total, 717 children with valid responses were included in the analysis. The mean age of the children was 9.08 ± 0.33 years; 366 (51.0%) were boys, and 351 (49.0%) were girls. For moderate-to-vigorous and vigorous PA, PA levels tended to be significantly higher in children whose parents provided logistic support such as enrolling their children in a sports club. However, for moderate PA and walking, PA levels tended to be significantly higher in children whose parents used community resources. Modeling and limiting sedentary activities were not associated with children's PA.

CONCLUSIONS

The results of this study suggest that direct parental assistance for PA such as logistic support encourages children to engage in moderate-to-vigorous PA; in addition, parental use of community resources may encourage children to engage in moderate and light PA such as walking. Conversely, indirect and negative involvement such as modeling and limiting sedentary activities were not associated with children's PA. Therefore, logistic support may need to be strengthened to encourage moderate-to-vigorous and vigorous PA, which is important for children's health.

Associations between 24-h movement behaviours and BMI in Chinese primary- and middle- school students

Purposes

This cross-sectional study aimed to examine the associations between the 24-h movement behaviours and body mass index (BMI) of students from China by using compositional data analysis.

Methods

A total of 389 students aged 6-16 years participated in this study. Accelerometers were used to measure moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LPA), sedentary behaviour (SED), and sleep. Weight and height were objectively measured. The association between 24-h movement and BMI was analyzed by using compositional data analysis.

Results

Time reallocation using minutes and proportions created major differences to the results. Reallocating 10 min from other movement behaviours to MVPA was associated with decreased BMI z-score of 1.372 to 0.158 among primary-school students. Reallocating 10 min from sleep and SED to MVPA, and from sleep and SED to LPA were associated with decreased BMI z-score of 0.505 to 0.017 among middle-school students. Reallocating 10% of time from all other components to SED and sleep were associated with a higher BMI z-score by 0.148 (95%CI: 0.020; 0.276) and 0.125 (95%CI: 0.046; 0.204), while reallocating time to MVPA was associated with a decrease in BMI z-scores of 0.132 (95%CI: -0.193; -0.070) among primary-school students. Reallocating 10% of time from all other components to SED was associated with a higher BMI z-score of 0.254 (95%CI: 0.165; 0.345), whereas reallocating time to MVPA and LPA was associated with a decrease in BMI z-scores of 0.039 (95%CI: -0.073; -0.005) and 0.093 (95%CI: -0.153; -0.033) among middle-school students.

Conclusion

Research results of 10-min one-to-one reallocation may be treated cautiously due to uneven distribution of time in 24-h movement behaviours. Based on the results of 10% one-to-remaining reallocation, replacing SED with MVPA may be an appropriate target for adiposity intervention in primary-school students, while increasing MVPA or LPA at the expense of SED may be effective in controlling adiposity of middle-school students in China.

Weekday and Weekend Differences in Eating Habits, Physical Activity and Screen Time Behavior among a Sample of Primary School Children: The "Seven Days for My Health" Project

BACKGROUND

Healthy eating and active lifestyle habits are essential for a child's development, wellbeing, and health. School setting and family environment play a crucial role in shaping these habits and this could be reflected in different behavior patterns during weekdays and weekends.

METHODS

We investigated primary school children's lifestyle habits through a cross-sectional analysis of 428 Italian primary school children, with a mean age of 8.99 years (±1.43). Data were collected from May to June 2017 using a weekly diary to assess children's lifestyles.

RESULTS

Children who eat their morning snack and lunch at school three or more times during the weekdays were 5.47 times more likely (95% CI 3.02, 10.2) to consume adequate snacks and 7.79 times more likely (95% CI 4.43, 14.5) to have adequate meals than those who did not.

CONCLUSION

Consumption of vegetables, lunch, and snacks are significantly more adequate during the weekdays as compared to the weekends. Physical activity levels did not differ between weekdays and weekends. Moreover, children spent more time engaged in physical activities than in front of a screen during both the weekdays and the weekends. The present results are good indicators of the importance of the school canteen in defining correct eating habits. Family-based and school-based interventions could represent valuable integrative strategies for promoting a healthy lifestyle in children.

Associations of greenness surrounding schools with blood pressure and hypertension: A nationwide cross-sectional study of 61,229 children and adolescents in China

BACKGROUND

Greenness exposure may lower blood pressure. However, few studies of this relationship have been conducted with children and adolescents, especially in low and middle-income countries.

OBJECTIVES

To evaluate associations between greenness around schools and blood pressure among children and adolescents across China.

METHODS

We recruited 61,229 Chinese citizens aged 6-18 years from 94 schools in a nationwide cross-sectional study in seven Chinese provinces/province-level municipalities. Participants' blood pressures and hypertension were assessed with standardized protocols. Greenness levels within 500 m and 1,000 m of each school were estimated with three satellite-based indices: vegetation continuous fields (VCF), normalized difference vegetation index (NDVI), and soil adjusted vegetation index (SAVI). Generalized linear mixed models were used to evaluate associations between greenness and blood pressure, greenness and prevalent hypertension, using coefficient and odds ratio respectively. Stratified analyses and mediation analyses were also performed.

RESULTS

One interquartile range increase in greenness was associated with a 17%-20% reduced prevalence of hypertension for all measures of greenness (odds ratios for VCF_500m = 20% (95% CI:18%, 23%); for NDVI_500m = 17% (95% CI:13%, 21%); and for SAVI_500m = 17% (95% CI: 13%, 20%). Increases in greenness were also associated with reductions in systolic blood pressure (0.48-0.58 mmHg) and diastolic blood pressure (0.26-0.52 mmHg). Older participants, boys, and urban dwellers showed stronger associations than their counterparts. No evidence of mediation was observed for air pollution (i.e., NO₂ and PM_2.5) and body mass index.

CONCLUSION

Higher greenness around schools may lower blood pressure levels and prevalent hypertension among Chinese children and adolescents, particularly in older subjects, boys, and those living in urban districts. Further studies, preferably longitudinal, are needed to examine causality.

Paternal and maternal support of moderate-to-vigorous physical activity in children on weekdays and weekends: a cross-sectional study

Background

Most studies of associations between parental support behaviours for physical activity (PA) and children’s moderate-to-vigorous physical activity (MVPA) have been conducted in developed countries, and they have focused on maternal or parental support behaviours. Children’s MVPA time (i.e., weekdays vs. weekends) has not been adequately differentiated. This paper investigated the associations of paternal and maternal support behaviours for PA with the proportion of children who met the MVPA recommendations on weekdays and weekends in China.

Methods

Cross-sectional data of 517 father–child dyads and 1422 mother–child dyads were analysed. The children recorded PA diaries on 7 consecutive days to assess their MVPA time. The father or mother completed a questionnaire concerning their support for children’s PA. Multivariate logistic regression was used to investigate the independent effects of paternal and maternal support behaviours for PA on whether children met the MVPA recommendations for weekdays, weekends, and the whole week.

Results

Significantly fewer children met the MVPA recommendations on weekends (37.8%) than on weekdays (62.8%). Higher paternal (odds ratio [OR] = 1.098, 95% confidence interval [CI]: 1.009–1.195) and maternal (OR = 1.076, 95% CI: 1.021–1.134) total support behaviour scores were associated with higher odds of children meeting the MVPA recommendations on weekends, after controlling for covariates. Paternal PA knowledge-sharing with the child was positively associated with children meeting the MVPA recommendations on weekends (OR = 1.319, 95% CI: 1.055–1.649); it tended to be associated with children meeting the MVPA recommendations on weekdays and throughout the week, although these associations were not statistically significant. Maternal reservation of PA time for the child was positively associated with a higher likelihood of children meeting the MVPA recommendations on weekdays (OR = 1.160, 95% CI: 1.025–1.313), weekends (OR = 1.241, 95% CI: 1.097–1.403), and throughout the week (OR = 1.214, 95% CI: 1.076–1.369).

Conclusions

Paternal and maternal support behaviours for PA should be enhanced on weekends to increase children’s MVPA. Fathers should share PA knowledge with children and mothers should reserve PA time for children every day.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11730-8.

The Impact of Physical Education Classes on Health and Quality of Life during the COVID-19

The purpose of this study was to examine the effects of the COVID-19 pandemic on the well-being and the quality of life of college students participating in physical education classes. We consider this study to be relevant because during the COVID-19 pandemic we tested whether the boost in effective activity among physical education class participants affected well-being and quality of life. A sectional questionnaire survey was conducted across Taiwan in 2019–2020. Data were collected in two stages within 6 months from a sample of 1011 university students in Taiwan (328 male, 683 female). A series of one-way ANOVAs was adopted to examine each outcome across groups and time phases. The results provide support for a positive relationship between well-being (β = 0.25, p < 0.001), and quality of life (β = 0.92, p < 0.001), supporting our expectations. Findings from our study suggest that physical activity was positively associated with mental health; and participation in physical activity had an effect on the well-being and quality of life in college students.

The study of Iranian children and adolescents' physical activity: a systematic review and meta-analysis

OBJECTIVES

This systematic and meta-analysis review was conducted to determine the status of Iranian children and adolescents' physical activity.

CONTENT

All the related articles which were published in the major databases, including Pubmed, Scopus, Web of Science, Embase, Magiran, SID from the beginning of 2010 to the end of 2019, were reviewed by researchers. The Newcastle-Ottawa scale was also used to evaluate the quality of articles. Moreover, I ² index and chi-square were used to assess the heterogeneity between the results.

SUMMARY

490 articles were found as a result of the search in the selected international and local databases, where finally, 10 articles were included into the meta-analysis after the elimination of the duplicated articles and applying inclusion and exclusion criteria. The results indicated that 29.5% of the girls were considered active according to WHO criteria (16.1-42.8: 95% CI) and also 20.5% of the boys (7.3-33.7: 95% CI).

OUTLOOK

Overall, this study's findings showed that a large percentage of Iranian children and adolescents do not achieve the level of physical activity recommended by the World Health Organization. This can lead to undesirable consequences for this group of population that is considered as the human capital of any country; consequently, it seems necessary to take basic measures at the micro and macro levels in order to reduce such problems in the society.

Parental and Familial Factors Influencing Physical Activity Levels in Early Adolescence: A Prospective Study

Parental/familial factors are important determinants of the physical activity level (PAL) in children and adolescents, but studies rarely prospectively evaluate their relationships. This study aimed to evaluate the changes in physical activity levels among adolescents from Bosnia and Herzegovina over a two-year period and to determine parental/familial predictors of PAL in early adolescence. A total of 651 participants (50.3% females) were tested at baseline (beginning of high school education; 14 years old on average) and at follow-up (approximately 20 months later). The predictors included sociodemographic characteristics (age, gender) and parental/familial factors (socioeconomic status of the family, maternal and paternal education, conflict with parents, parental absence from home, parental questioning, and parental monitoring). Physical activity levels were evidenced by the Physical Activity Questionnaire for Adolescents (PAQ-A; criterion). Boys were more active than girls, both at baseline (t-test = 3.09, p < 0.001) and at follow-up (t-test = 3.4, p < 0.001). Physical activity level decreased over the observed two-year period (t-test = 16.89, p < 0.001), especially in boys, which is probably a consequence of drop-out from the sport in this period. Logistic regression evidenced parental education as a positive predictor of physical activity level at baseline (OR [95% CI]; 1.38 [1.15–170], 1.35 [1.10–1.65]), and at follow-up (1.35 [1.11–1.69], 1.29 [1.09–1.59], for maternal and paternal education, respectively). Parents with a higher level of education are probably more informed about the importance of physical activity on health status, and thus transfer this information to their children as well. The age from 14 to 16 years is likely a critical period for maintaining physical activity levels in boys, while further studies of a younger age are necessary to evaluate the dynamics of changes in physical activity levels for girls. For maintaining physical activity levels in adolescence, special attention should be paid to children whose parents are less educated, and to inform them of the benefits of an appropriate physical activity level and its necessity for maintaining proper health and growth.

Motivational climate, need satisfaction, self-determined motivation, and physical activity of students in secondary school physical education in China

Background

On the basis of the integration constructs from self-determination theory (SDT) and achievement goal theory (AGT), this study aims to investigate the relationship among classroom motivational climate from four perspectives (i.e. autonomy support, relatedness support, task-involving climate and ego-involving climate), three psychological needs (i.e. autonomy, competence and relatedness), self-determined motivation and physical activity (PA) in secondary physical education (PE).

Methods

Participants consisted of 1186 Chinese students aged 11 to 16 years from three secondary schools in Shanghai. Accelerometers were utilized to measure moderate to vigorous physical activity (MVPA). Questionnaires were used to measure SDT variables (i.e. classroom motivational climate, perceived competence, autonomy, relatedness and self-determined motivation). Structural equation modelling (SEM) was adopted to analyse the hypothesised relationship.

Results

SEM analysis revealed that task-involving climate and autonomy support were positively associated with autonomy, relatedness and competence. Relatedness support was positively related with autonomy and relatedness, whereas ego-involving climate was only associated with competence. The three psychological needs positively affected self-determined motivation, and self-determined motivation positively affected the MVPA time of secondary school students in PE lessons.

Conclusion

These findings support a model of motivation that integrates SDT and AGT, provides new insight into understanding MVPA in Chinese PE, and establishes a solid basis for intervention research.

Ethnicity, socioeconomic status and the nutritional status of Chinese children and adolescents: Findings from three consecutive national surveys between 2005 and 2014

BACKGROUND

Economic development has brought rapid shifts in the food environment of Chinese children and adolescents.

OBJECTIVES

To assess the changes in childhood nutritional status across ethnic groups and economic status from 2005 to 2014.

METHODS

664 094 Chinese Han and 224 151 ethnic minority children and adolescents aged 7 to 18 years were assessed in three national cross-sectional surveys (2005, 2010 and 2014). Gross domestic product (GDP) per capita of each ethnic group was categorized into four strata of socioeconomic status. To assess ethnic disparities at each time point, we used logistic regression to estimate the prevalence odds ratios (OR) for thinness, overweight and obesity in the 24 ethnic minority groups vs Han Chinese.

RESULTS

Children in the two upper economic strata (over about US$4000 GDP per capita) had a high prevalence of overweight and obesity, while those in the two lower economic strata (below US$4000 GDP per capita) had a high prevalence of thinness. From 2005 to 2014, the prevalence of thinness decreased from 18.6% to 13.1% in Han children, and from 20.4% to 17.1% in ethnic minority students. At the same time, the prevalence of overweight and obesity increased from 10.4% to 17.7% in Han children, and from 4.3% to 9.2% in ethnic minority students, respectively.

CONCLUSIONS

A rapid nutritional transition has occurred from 2005 to 2014 with shifts from thinness to overweight and obesity in both Han and ethnic minority children and adolescents, reflecting local GDP per capita.

The Relationship Between Physical Activity and Inhibition in Children With and Without Motor Impairments

BACKGROUND

To examine the relationship between physical activity (PA) and inhibition in boys and girls with motor impairments compared with children with typical development.

METHODS

The participants were 58 (26 motor impairments and 32 typical development) children aged 7-12 years who met the inclusion criteria. PA was assessed using accelerometers for 7 consecutive days. The time spent in PA of different intensity levels (light, moderate, and vigorous) were analyzed for weekdays and weekends. Using a visuospatial attention paradigm, inhibition was evaluated by the difference in reaction time between invalid and valid cue conditions. Generalized linear mixed models were used to determine the associations of inhibition with PA and motor ability by sex.

RESULTS

Boys and children with typical development had shorter reaction times in inhibition than girls (P < .001) and children with motor impairments (P < .05), respectively. Motor ability (b = 189.98) and vigorous PA on weekdays (b = -43.18) were significant predictors of inhibition in girls only.

CONCLUSIONS

The results indicate a positive relationship between vigorous PA (on weekdays) and inhibition in children (girls), moderated by sex and motor ability. Effective interventions that promote vigorous PA for children both in and out of school should be designed to foster their executive function development.

Accelerometer-Assessed Habitual Physical Activity and Sedentary Time of Chinese Children and Adolescents with Visual Impairments

Introduction:

Physical activity is a key component of a healthy lifestyle for youths with visual impairments (i.e., blindness or low vision). This study aims to examine the habitual physical activity and sedentary time of Chinese children and adolescents with visual impairments and to determine whether age, gender, and body composition significantly influence their behavior.

Methods:

A purposeful sample method was utilized to recruit 137 Chinese youths with visual impairments from a special school for individuals with visual and hearing impairments. A total of 72 students with visual impairments (aged 7–17 years; M age = 13.4) participated in this study. ActiGraph GT3X accelerometers were used to measure the habitual physical activity and sedentary time.

Results:

Youths with visual impairments in this study spent an average of 287.86 (standard deviation [ SD] = 45.67) minutes of light physical activity, 146.79 ( SD = 56.95) minutes of moderate physical activity, 18.47 ( SD = 15.15) minutes of vigorous physical activity, 165.26 ( SD = 69.83) minutes of moderate-to-vigorous-intensity physical activity, and 979.51 ( SD = 109.10) minutes of sedentary time per day. Children with visual impairments in elementary school engaged in more habitual physical activity and had less sedentary time than did students in middle and high school. Differences in gender and body composition with regard to time spent being active or sedentary were insignificant.

Discussion:

Findings demonstrated that Chinese youths with visual impairments in this study had sufficient health-enhancing physical activity and were habitually active. Future research is needed to identify the factors that account for the high habitual physical activity levels of Chinese youths with visual impairments.

Implications for practitioners:

Transition planning for students with visual impairments to facilitate active habitual physical activity participation when children grow up is warranted.

Accelerometer-measured physical activity and sedentary behavior in Chinese children and adolescents: a systematic review and meta-analysis

OBJECTIVE

To synthesize evidence on accelerometer-measured moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SB) levels of Chinese children and adolescents.

STUDY DESIGN

This is both a systematic review and meta-analysis study.

METHODS

Online databases were searched for studies published from January 2009 up to February 2019. These studies reported accelerometer-measured daily minutes of MVPA and/or SB among Chinese children and adolescents. Random-effects meta-analysis was used to separately pool the time spent in MVPA and SB.

RESULTS

Of 4754 records, 20 studies were included in the meta-analysis. Sample sizes ranged from 96 to 2163. The meta-analysis showed that Chinese children and adolescents spent 41.11 min/day in MVPA and 529.83 min/day in SB averagely. Boys spent more time in MVPA compared with girls (P = 0.01). Children accumulated more MVPA time than adolescents (P = 0.05), and children spent less time in SB than adolescents (P = 0.05). Unlike weekdays, SB was lower on weekends (P = 0.02). There were significant differences in children and adolescents' MVPA time in regions (P < 0.001).

CONCLUSIONS

MVPA level in Chinese children and adolescents is well below international recommendations, and their SB level is very high.

Sedentary Behavior Research in the Chinese Population: A Systematic Scoping Review

Background: The negative effects of sedentary behavior (SB) on public health have been extensively documented. A large number of studies have demonstrated that high prevalence of SB is a critical factor of all-cause mortality. Globally, the frequency of SB research has continued to rise, but little is known about SB in the Chinese population. Therefore, this review was conducted to scope the research situation and to fill the gaps related to the effects of SB in the Chinese population. Methods: Using a scoping review based on York methodology, a comprehensive search of published journal articles and grey literature was carried out through 12 databases. The literature research was conducted by two authors in July 2019, and included journal articles that targeted on the Chinese population were published between 1999 and 2019. The two authors screened the records independently and included those research topics related to SB in the Chinese population. Results: The number of included studies increased from 1 to 29 per year during the analyzed period, during which, a remarkable climb happened from 8 in 2013 to 19 in July 2019. Out of the 1303 screened studies, a total of 162 studies (81 English and 81 Chinese journal articles) met the inclusion criteria in this review. Most of the included studies (66.0%) reported the overall estimated prevalence of SB, in which, 43.2% of studies reported the average time of SB, and 40.0% of studies reported the cutoff point of SB. Besides this, 54.9% and 23.5% of studies focused on the outcomes and correlates/determinants of SB, and the proportions of studies based on testing the validation of measurement tools and on interventions were 3.7% and 4.9%, respectively. Nearly all of the reviewed articles used data from cross-sectional studies (75.9%) and longitudinal studies (13.6%), while intervention trials are less developed. The majority of the studies (64.8%) used self-reported surveys, and only 3.7% studies used device-based measurement tools. Furthermore, 35.8% of the included studies were focused on children and adolescents, while only a few studies investigated infants/toddlers and older adults. Both female and male were examined in most studies, and non-clinical populations were investigated in the context of SB in a relatively large number of studies. Conclusions: The number of research articles on SB in the Chinese population published per year has increased year by year, indicating a growing interest in this research area. More studies using population subgroup samples are needed, particularly among infants/toddlers, older adults, and clinical populations. To provide stronger evidence of the determinants and outcomes of SB, longitudinal studies using device-based measures of SB are required.

Specific Features of the Ukrainian Urban Adolescents' Physical Activity: A Cross-Sectional Study

Background

An increase in the proportion of physically active peoples is one of the public health priorities. Particular attention should be addressed to the adolescent group with regard to their sensitivity. The purpose of our study is to determine the overall level of physical activity (PA) of urban adolescents and to evaluate its components.

Methods

The study included the results of a survey of 415 children aged 11–15 years from public schools in Ukraine. We have adapted the standardized questionnaire QAPACE, which allows characterizing the level of adolescent's PA by indicators: type, duration, and intensity.

Results

A sedentary lifestyle is typical for most Ukrainian urban adolescents. Only 30.8% of Ukrainian urban adolescents (45.4% of boys and 21.4% of girls; p < 0.001) meet the recommended level of moderate-to-vigorous PA (at least 60 minutes per day). The chances to follow the recommended moderate-to-vigorous PA are almost 5 times higher in the group of adolescents exercising at their own wish and not by parents' direction (OR = 4.96; 95% CI: 2.77–8.90; p < 0.001). Girls have a 3.0 higher chance of not adhering to recommendations for duration of PA (OR = 3.01; 95% CI: 1.95–4.63). They are 2.5 times more likely to lead a sedentary lifestyle (OR = 2.48; 95% CI: 1.54–3.98) than boys.

Conclusion

The obtained results are indicative of a lack of implementation of measures to increase physical activity, which requires public attention to this problem. A search for ways to improve public policy towards optimizing adolescents' PA is still an urgent goal for scholars and practitioners. PA-promoting measures should be developed taking into account the impact of family traditions, accessibility of sports facilities, leisure, advertising, and other factors. The obtained results are the initial stage for developing the program of physical inactivity prevention.

Prevalence of Physical Activity and Sedentary Behavior among Chinese Children and Adolescents: Variations, Gaps, and Recommendations

Physical-activity (PA) and sedentary-behavior (SB) assessment is of particular importance in the promotion of health in young people. However, there is no comprehensive overview of PA and SB from national surveys among Chinese children and adolescents. Following a literature search for Chinese national health surveys, 11 papers from six national surveys were found. Of the included studies, the majority applied self-reported questionnaires to estimate the prevalence of PA and SB. Owing to different definitions of the prevalence of PA and SB and various measures, a large variation in prevalence of PA and SB was observed. Such variations were attributable to methodological and practical issues. This study highlights the current gaps in estimating the national prevalence of PA and SB among Chinese children and adolescents, which should be addressed. To improve the quality of PA and SB surveillance, standardized measurement protocols to estimate the prevalence of PA and SB more accurately among Chinese children and adolescents are urgently required.

The Influence of Social Support on Physical Activity in Chinese Adolescents: The Mediating Role of Exercise Self-Efficacy

The purpose of this study was to examine the associations of social support and self-efficacy with physical Activity (PA) and the mediating effect of self-efficacy on the relationship between social support and PA in Chinese adolescents. Participants included a total of 2341 Chinese adolescents (aged 12.75 ± 1.46 years). Self-reported instruments, including the physical activity questionnaire for adolescents, the social support revalued scale and the exercise self-efficacy scale, were used to measure physical activity, social support and exercise self-efficacy. Results showed that social support (r = 0.29, p < 0.05) and exercise self-efficacy (r = 0.43, p < 0.05) were significant and positive predictors of PA among Chinese adolescents, and exercise self-efficacy was a significant mediator in the relationship between social support and PA (standardized effect size = 0.15, p < 0.001). Such findings were evident with similar patterns in both male and female adolescents. The findings of this study have indicated the importance of social support and exercise self-efficacy on PA promotion in adolescents, which will aid the development of effective interventions in this population.

Gender and age differences in the association between living arrangement and physical activity levels among youth aged 9-19 years in Shanghai, China: a cross-sectional questionnaire study

BACKGROUND

We examined the correlations between living arrangement and the physical activity (PA) levels of youth aged 9-19 years while accounting for demographic factors such as age, sex, and socioeconomic status in Shanghai, China.

METHODS

Cross-sectional analyses of data from the 2014 Physical Activity and Fitness in Shanghai China-The Youth Study was conducted. Participants were 33,213 primary (9-11-year-olds; n = 13,237), junior middle (12-14-year-olds; n = 11,157), and junior high school students (15-19-year-olds; n = 8819). Youth (boys = 49%) and their guardians were randomly sampled from 17 districts in Shanghai, China. Youths' moderate-to-vigorous PA (MVPA) levels, information about living arrangement, and guardians' sociodemographic factors were collected via questionnaires.

RESULTS

Only 17.8% of school-aged youths in Shanghai met MVPA recommendations, with significantly more boys (20.6%) meeting recommendations than girls (p < .001). Youths living in rural areas showed an overall significantly higher percentage of meeting MVPA recommendations (20.3%) than those living in urban areas (p < .001). Youths who lived with single parents showed an overall significantly lower percentage of meeting MVPA recommendations (15.3%) than those living with their grandparent(s) or with both parents (p < .001). A logistic regression analysis revealed that, among 9-11-year-olds, children who live with their grandparent(s) were less likely to meet MVPA recommendations than those who lived with both parents (boys: adjusted odds ratio (aOR) = 0.72, 95% confidence interval (CI) = 0.61-0.84; girls: aOR = 0.84, 95%CI = 0.72-0.98).

CONCLUSIONS

Type of living arrangement was associated with the PA of youth in Shanghai, with no significant gender difference. Youth aged 9-19 years who lived with single parents had the lowest percentage of meeting MVPA recommendations. The probability of achieving 60 min/day MVPA recommendations was significantly lower among 9-11-year-old children living with their grandparent(s) than children living with both parents; however, no such difference was observed among adolescents. Our findings suggest that living arrangement may be an important consideration for promotion of PA among youth in China.

Accelerometer-Measured Physical Activity in Children and Adolescents at Altitudes over 3500 Meters: A Cross-Sectional Study in Tibet

There is a scarcity of studies on the physical activity (PA) of children and adolescents who live at high altitudes. This study aimed to objectively assess PA of children and adolescents living in the Tibet at altitudes over 3500 m and to examine its difference by ethnicity, gender, age/grade, and body weight status groups. A sample of 397 students aged 9–18 years were recruited from 7 schools in Lhasa, Tibet. PA was measured using accelerometers (ActiGraph GT3X) for seven consecutive days and moderate to vigorous PA (MVPA) was identified using the Evenson (2008) cut-points. Participant MVPA was 62.3 min/day, with 65.5 min/day during weekdays and 54.1 min/day on weekends. Indigenous Tibetans were more active than Hans, and boys had more MVPA than girls. Age had a significantly weak negative correlation with MVPA. There was no significant difference in MVPA between the non-overweight and overweight/obese groups. Overall, only 9.1% (13.8% in boys and 4.5% in girls) accumulated at least 60 min of MVPA per day. Compared to their counterparts in other regions, the daily MVPA of children and adolescents living on the Tibetan Plateau at altitudes over 3500 m was relatively high. However, the proportion of meeting the WHO’s PA recommendations was extremely low.

Measurement invariance and latent mean differences of the Chinese version physical activity self-efficacy scale across gender and education levels

BACKGROUND

Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity (PA) participation. However, the dimensionality check of a PA self-efficacy scale has rarely been conducted in China. The current study aims to examine (1) the unidimensionality of a shortened Chinese version of PA self-efficacy scale (S-PASESC); (2) the measurement invariance of S-PASESC across gender and levels of education; (3) the latent factor mean difference between gender and levels of education; (4) the direct effects of self-efficacy on PA by different gender and education levels; and (5) the comparisons of the direct effects of self-efficacy on PA across gender and education levels.

METHODS

The participants were 5th through 11th grade public school students recruited from 7 cities located in different geographic regions of China. The final data include a total of 3003 participants (49.7% boys) who have completed the scales.

RESULTS

Confirmatory factor analysis (CFA) test supported the unidimensionality of S-PASESC. The S-PASESC is invariant across gender and 3 levels of education at both configural, full metric, and full scalar levels. Findings from latent mean comparisons showed that boys reported higher PA self-efficacy than girls. Students' perceived PA self-efficacy tend to decrease from elementary to high school. Finally, self-efficacy positively related to PA by groups of different gender and education levels and the relationship between self-efficacy and PA is stronger among middle school boys than girls.

CONCLUSION

Findings suggest S-PASESC is a valid scale for measuring Chinese students' PA self-efficacy.

Investigating Motor Competence in Association with Sedentary Behavior and Physical Activity in 7- to 11-Year-Old Children

Children's motor competence (MC) has declined in the past decades, while sedentary behavior (SB) has increased. This study examined the association between MC and physical activity (PA) levels among primary schoolchildren. Demographics, body height and weight, MC (Athletic Skills Track), and PA levels (ActiGraph, GT3X+) were assessed among 595 children (291 boys, mean age = 9.1 years, SD = 1.1). MC was standardized into five categories: from very low to very high. PA levels were classified into SB, light PA (LPA), and moderate-to-vigorous PA (MVPA). Mixed-model analyses were conducted with PA levels as dependent variables and MC as the independent variable, while adjusting for age, gender, and body mass index (BMI) z-score on the individual level. A negative association between MC and SB and a positive association between MC and MVPA were found. The strength of both associations increased as children expressed lower or higher levels of MC. MC is an important correlate of both SB and MVPA, particularly for children with very high or low MC. Developing and improving children's MC may contribute to spending less time in SB and more time in MVPA, particularly for high-risk groups, i.e., children with low MC. Moreover, addressing MC development and PA promotion simultaneously might create positive feedback loops for both children's MC and PA levels.

Objectively Measured Physical Activity and Sedentary Time among Children and Adolescents in Morocco: A Cross-Sectional Study

Background

Regular physical activity in childhood and adolescent plays an important role in reducing the risk of cardiovascular health diseases, diabetes, and obesity in adulthood. However, little is known about physical activity levels (PA) and sedentary time among children and adolescents in Morocco.

Objective

To examine gender, type of day, and age grade differences in objectively measured sedentary time, physical activity levels, and physical activity guideline attainment among children and adolescents in Morocco.

Method

172 children/adolescents (mean age = 10.92 ± 1.55 years, 49.4% are boys) were recruited for this study and wore a tri-axial accelerometer (GT3X+) for 7 consecutive days. Time spent in sedentary, PA levels, and daily steps were measured and compared according to gender, age grade, and the type of day (weekdays/weekends).

Results

In weekdays children/adolescents spent more time in sedentary than weekends (p < 0.001). Boys were eight times more likely to meet the recommendation for at least 60 min of moderate to vigorous physical activity per day than girls (OR: 8.569; 95% [CI]: 4.23–17.32), p < 0.001.

Conclusion

These findings highlight the need for effective and sustainable strategies and programs aiming to promote physical activity and to reduce sedentary behavior among children and adolescents in Morocco.

Teaching Games for Understanding Intervention to Promote Physical Activity among Secondary School Students

Objectives

This study investigated the effectiveness of Teaching Games for Understanding (TGfU) intervention on the moderate-to-vigorous physical activity (MVPA) levels of students from Grades 9 and 10.

Methods

A total of 118 students from four classes (two TGfU groups and two technique groups) participated in this study. Accelerometers were used to measure the MVPA time of students, and formal interviews were conducted to identify the factors that contributed to the MVPA level of students in TGfU classes.

Results

The results reveal that the TGfU [t (1, 57) = - 11.622, p <.001, and d =.841] and technical [t (1, 61) = -4.232, p <.001, and d =.236] group exhibited significantly improved MVPA levels in intervention phase. During the intervention period, the MVPA time of the TGfU group (M = 20.26, SD = 3.74) was significantly longer than that of the technique group [M = 17.62, SD = 3.37, t (1, 118) = 4.023, p < .001, and d = .35]. Moreover, in the TGfU classes, boys (M=21.476, SD =.719) spent significantly more time engaging in MVPA than girls (M = 19.135, SD = .645) [F (1, 57) = 5.807, p = .019, and η²= .09]. However, no significant differences were determined between the MVPA levels of high- and low-skilled students. Data gathered through interviews suggested that the nature of the games, the small-sided team, and the freedom and enjoyment experienced by the students through games may explain the high MVPA levels observed in the TGfU classes.

Conclusion

TGfU intervention can potentially be used to promote physical activities and attain the recommended MVPA time in PE classes (50% class time).

Secular Trends in Blood Pressure and Overweight and Obesity in Chinese Boys and Girls Aged 7 to 17 Years From 1995 to 2014

The current study aimed to assess the secular trends in overweight and obesity status and high blood pressure (HBP) in Chinese children and adolescents for 2 decades. Data on 943 128 participants aged 7 to 17 years were obtained from the Chinese National Survey on Students' Constitution and Health from 1995 to 2014. The population attributable risk of overweight status for HBP was calculated. The prevalence of overweight increased from 4.3% in 1995 to 18.4% in 2014, whereas HBP prevalence fluctuated in the range of 4.4% to 6.4% during the same time period, the lowest in 2005. Within each survey year, blood pressure levels and HBP prevalence increased with higher body mass index. Notably, the population attributable risk of HBP because of being overweight steadily increased from 6.3% in 1995 to 19.2% in 2014. The same trends of linear growth for obesity, fluctuating blood pressure, and its sustained increasing population attributable risk for overweight also occurred among the domestic 29 provinces. Despite dramatic increases in overweight prevalence among Chinese children from 1995 to 2014, the HBP prevalence remained relatively stable, suggesting that other independent factors are affecting HBP trends to a greater extent. Yet, over time, the magnitude of the impact of being overweight or obese on HBP increased sharply, predicting looming heavy burden of HBP. Reductions in overweight status may aid in preventing HBP so as to prevent coronary risk in adulthood.

Comparison of accelerometer measured levels of physical activity and sedentary time between obese and non-obese children and adolescents: a systematic review

Background

Obesity has been hypothesized to be associated with reduced moderate-to-vigorous physical activity (MVPA) and increased sedentary time (ST). It is important to assess whether, and the extent to which, levels of MVPA and ST are suboptimal among children and adolescents with obesity. The primary objective of this study was to examine accelerometer-measured time spent in MVPA and ST of children and adolescents with obesity, compared with MVPA recommendations, and with non-obese peers.

Methods

An extensive search was carried out in Medline, Cochrane library, EMBASE, SPORTDiscus, and CINAHL, from 2000 to 2015. Study selection and appraisal: studies with accelerometer-measured MVPA and/or ST (at least 3 days and 6 h/day) in free-living obese children and adolescents (0 to 19 years) were included. Study quality was assessed formally. Meta-analyses were planned for all outcomes but were precluded due to the high levels of heterogeneity across studies. Therefore, narrative syntheses were employed for all the outcomes.

Results

Out of 1503 records, 26 studies were eligible (n = 14,739 participants; n = 3523 with obesity); 6/26 studies involved children aged 0 to 9 years and 18/26 involved adolescents aged 10.1 to19 years. In the participants with obesity, the time spent in MVPA was consistently below the recommended 60 min/day and ST was generally high regardless of the participant’s age and gender. Comparison with controls suggested that the time spent in MVPA was significantly lower in children and adolescents with obesity, though differences were relatively small. Levels of MVPA in the obese and non-obese were consistently below recommendations. There were no marked differences in ST between obese and non-obese peers.

Conclusions

MVPA in children and adolescents with obesity tends to be well below international recommendations. Substantial effort is likely to be required to achieve the recommended levels of MVPA among obese individuals in obesity treatment interventions.

This systematic review has been registered on PROSPERO (International Database of Prospective Register Systematic Reviews; registration number CRD42015026882).

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1031-0) contains supplementary material, which is available to authorized users.

Impact of parents' physical activity on preschool children's physical activity: a cross-sectional study

Purpose

This study examined the associations of physical activity levels between parents and their pre-school children based on gender and weekday/weekend.

Method

A total of 247 parent-preschool child triads from Shanghai, China were analyzed. The children had a mean age of 57.5 ± 5.2 months. Both sedentary behavior and physical activity were measured in all participants using an ActiGraph GT3X⁺ accelerometer over seven consecutive days from Monday through the following Sunday. A multivariate regression model was derived to identify significant relationships between parental and child physical activity according to gender and weekday/weekend.

Results

There was a significant correlation between mothers’ and girls’ moderate-to-vigorous physical activity (MVPA) and total physical activity (TPA) on weekdays. Fathers’ MPVA levels correlated significantly with those of boys and girls, with paternal influence appearing to be stronger than maternal influence. However, there was not a significant correlation between fathers’ and children’s TPA. TPA levels of both mothers and fathers correlated with those of girls, but not with those of boys. Parental sedentary levels on the weekend correlated significantly with girls’ levels, but not with boys’ levels. Children’s physical activity levels on weekends were influenced more by fathers’ activity levels than by mothers’, while the opposite was observed on weekdays.

Conclusion

Sedentary behavior and physical activity levels of parents can strongly influence those of their preschool children, with maternal influence stronger during the weekdays and paternal influence stronger on the weekends. Parents’ activity levels influence girls’ levels more strongly than they influence boys’ levels.

Prevalence and Demographic Correlates of Overweight, Physical Activity, and Screen Time Among School-Aged Children in Urban China: The Shanghai Study

This study reports the prevalence and demographic correlates of overweight, as well as meeting physical activity and screen time guidelines, in Chinese children. A representative sample of school-aged children ( n = 49 549) in Shanghai were participants. Children's anthropometrics were objectively measured; their physical activity and screen time, and demographic variables including age, sex, skill proficiency, sport affiliation, and transportation mode were self-reported. Multivariate logistic regression analyses were conducted. The prevalence of overweight was 24.9%, meeting physical activity guidelines was 20.5%, and meeting screen time guidelines was 73.5%. Boys (odds ratio [OR] = 1.60, 95% confidence interval [CI] = 1.50-1.71) had higher overweight prevalence than girls. Girls (OR = 0.91, 95% CI = 0.85-0.97) and those without sport affiliation (OR = 0.48, 95% CI = 0.42-0.54) were less likely to meet physical activity recommendations than their counterparts. Girls were more likely than boys to meet screen time recommendations (OR = 1.29, 95% CI = 1.22-1.37). Children's sex, sport affiliation, and skill proficiency are factors that policymakers can use to improve body weight status, physical activity participation, and screen time.

Yoga versus physical exercise for cardio-respiratory fitness in adolescent school children: a randomized controlled trial

Background Yoga is very effective in improving health especially cardio-respiratory fitness and also overall performance in adolescents. There are no large numbers of randomized controlled studies conducted on comparing yoga with physical activity for cardio-respiratory fitness in adolescent school children with large sample size. Objective Aerobic training is known to improve physical and cardio-respiratory fitness in children. Cardio-respiratory fitness is an important indicator of health in children. In this study we evaluate the effects of yoga versus physical exercise training on cardio-respiratory fitness in adolescent school children. Subjects Eight hundred two school students from 10 schools across four districts were recruited for this study. Methods In this prospective two arm RCT around 802 students were randomized to receive daily one hour yoga training (n = 411) or physical exercise (n = 391) over a period of two months. VO2 max was estimated using 20 m shuttle run test. However, yoga (n = 377) and physical exercise (n = 371) students contributed data to the analyses. Data was analysed using students t test. Results There was a significant improvement in VO2 max using 20 m Shuttle run test in both yoga (p < 0.001) and exercise (p < 0.001) group following intervention. There was no significant change in VO2 max between yoga and physical exercise group following intervention. However, in the subgroup with an above median cut-off of VO2 max; there was a significant improvement in yoga group compared to control group following intervention (p = 0.03). Conclusion The results suggest yoga can improve cardio-respiratory fitness and aerobic capacity as physical exercise intervention in adolescent school children.

Physical Activity and Sedentary Behaviors of Urban Chinese Children: Grade Level Prevalence and Academic Burden Associations

The objectives of this study were (a) to report grade level prevalence in physical activity and sedentary behaviors and (b) to examine academic burden associations with these behaviors. School-aged children (n = 48,118) reported their physical activity, perception of physical activity sufficiency, factors for activity insufficiency, homework hours, and screen time in a typical week. Data were analyzed using general linear models and logistic regression models of Complex Samples. Prevalence results showed that children had lower physical activity and lower screen viewing time, but higher homework time during transition grades (6th, 9th, and 12th) and high school years. Academic burden was cited as the primary reason for not having sufficient physical activity (76.6%). Compared to those citing academic burden, students who did not report academic burden were significantly more likely to meet physical activity guidelines (Odds Ratio (OR) = 5.38, 95% CI = 4.74–6.11), but less likely to meet screen time guidelines (OR = 0.78, 95% CI = 0.72–0.84), controlling for body mass index, gender, and grade level. Additionally, children who reported academic burdens had significantly longer average daily homework time than those who did not (p < 0.01). Policy makers should promote physical activity and help children find a balance between homework and physical activity time particularly among the educational transition grades.

Prevalence of physical fitness in Chinese school-aged children: Findings from the 2016 Physical Activity and Fitness in China-The Youth Study

PURPOSE

This study was to present the 2016 prevalence estimates of Chinese school-aged children meeting physical fitness standards and to examine differences by sex and residence locales in children who did not meet fitness standards.

METHODS

We conducted cross-sectional analyses of 171,991 children and adolescents (boy: 50.0%, Grades 1-12) who participated in the 2016 Physical Activity and Fitness in China-The Youth Study. The main outcomes were fitness measures, assessed by the 2014 revised Chinese National Student Physical Fitness Standard (CNSPFS), covering areas of aerobic capacity, upper body strength, flexibility, body mass index, abdominal strength, and trunk strength. Children's overall physical fitness performance was categorized, per CNSPFS standards, as excellent, good, pass, or no pass. Data on the prevalence of physical fitness categories and not meeting fitness standards (i.e., among children who received a "no pass" mark) were analyzed, through logistic regression, by sex (boy, girl) and residence locales (urban, rural) across 3 school grades (primary, junior middle, and junior high).

RESULTS

In 2016, 5.95% of Chinese children and adolescents achieved an "excellent" mark, 25.80% received a "good" rating, 59.90% received a "pass", and 8.35% received a "no pass". Overall, boys were more likely to not pass the fitness standards compared with girls (adjusted odds ratio (aOR) = 1.710; 95% confidence interval (CI): 1.708-1.712) and children living in urban areas were more likely to not pass the standards than those living in rural areas (aOR = 1.298; 95%CI: 1.296-1.299). Consistent patterns of not meeting fitness standards were also found by sex and residence locales across all 3 school grades.

CONCLUSION

In the Chinese school-aged population, about 3 in 10 children achieved an "excellent" or "good" fitness standard in 2016, and about 8% of this population did not meet CNSPFS standards. Children living in urban areas were more likely to not meet minimum fitness performance levels, and boys in school were more likely to not meet minimum fitness performance levels than girls.

Physical activity among Chinese school-aged children: National prevalence estimates from the 2016 Physical Activity and Fitness in China-The Youth Study

PURPOSE

This study was to present national estimates of participating in moderate-to-vigorous physical activity (MVPA) and adherence to the recommendations of 60 min/day of MVPA among Chinese school-aged children and to assess demographic differences in MVPA.

METHODS

Cross-sectional analyses of data from the 2016 Physical Activity and Fitness in China-The Youth Study. Participants were 90,712 primary, junior middle, and junior high school children (boy: 47%; girl: 53%), recruited from 1204 rural and urban schools across 32 administrative provinces and regions in the Mainland of China. Main outcomes were (a) average MVPA minutes per day in the previous 7 days by self-reports and (b) percentage meeting MVPA recommendations.

RESULTS

Average MVPA time was 45.4 min/day, with boys having more MVPA (47.2 min/day) than girls (43.7 min/day) overall and across the 3 school grade categories. About 30% of participants met MVPA recommendations, with a higher percentage of boys (32%) than girls (28%) overall and across the 3 grades categories. Urban school children outperformed rural children in terms of MVPA time. Overall, boys were more likely to meet MVPA recommendations (adjusted odds ratio (aOR) = 1.19, 95% confidence interval (CI): 1.16-1.22) compared with girls; children in higher grades (junior middle (aOR = 0.92, 95%CI: 0.87-0.98) and junior high (aOR = 0.59, 95%CI: 0.53-0.66)) were less likely to meet recommendations compared with primary school children. The odds of meeting recommendations did not differ between urban and rural children (p = 0.07), but urban boys were found to be more likely to meet recommendations compared with rural boys (aOR = 1.14, 95%CI: 1.06-1.19).

CONCLUSION

Overall, the average MVPA minutes per day among Chinese school-aged children is low, and less than one-third of them meet MVPA recommendations. These results were most evident among junior middle and junior high school children and those living rural areas.

Understanding differences between summer vs. school obesogenic behaviors of children: the structured days hypothesis

BACKGROUND

Although the scientific community has acknowledged modest improvements can be made to weight status and obesogenic behaviors (i.e., physical activity, sedentary/screen time, diet, and sleep) during the school year, studies suggests improvements are erased as elementary-age children are released to summer vacation. Emerging evidence shows children return to school after summer vacation displaying accelerated weight gain compared to the weight gained occurring during the school year. Understanding how summer days differ from when children are in school is, therefore, essential.

DISCUSSION

There is limited evidence on the etiology of accelerated weight gain during summer, with few studies comparing obesogenic behaviors on the same children during school and summer. For many children, summer days may be analogous to weekend days throughout the school year. Weekend days are often limited in consistent and formal structure, and thus differ from school days where segmented, pre-planned, restrictive, and compulsory components exist that shape obesogenic behaviors. The authors hypothesize that obesogenic behaviors are beneficially regulated when children are exposed to a structured day (i.e., school weekday) compared to what commonly occurs during summer. This is referred to as the 'Structured Days Hypothesis' (SDH). To illustrate how the SDH operates, this study examines empirical data that compares weekend day (less-structured) versus weekday (structured) obesogenic behaviors in U.S. elementary school-aged children. From 190 studies, 155 (~80%) demonstrate elementary-aged children's obesogenic behaviors are more unfavorable during weekend days compared to weekdays.

CONCLUSION

In light of the SDH, consistent evidence demonstrates the structured environment of weekdays may help to protect children by regulating obesogenic behaviors, most likely through compulsory physical activity opportunities, restricting caloric intake, reducing screen time occasions, and regulating sleep schedules. Summer is emerging as the critical period where childhood obesity prevention efforts need to be focused. The SDH can help researchers understand the drivers of obesogenic behaviors during summer and lead to innovative intervention development.

"Are Thai children and youth sufficiently active? prevalence and correlates of physical activity from a nationally representative cross-sectional study"

Background

Children and youth gain multiple health benefits from regular participation in physical activity (PA). However, in Thailand there is limited national data on children and youth’s PA behaviors and recent reports suggest that Thai children and youth have low levels of PA. Furthermore, there is almost no data on the factors associated with inactivity to support the development of a Thai National PA Plan. The purpose of this paper is to investigate Thai children and youth’s participation in PA and its correlates across sociodemographic characteristics and different PA domains.

Methods

This study applied a cross-sectional study design with a multi-stage stratified cluster sampling. A national representative sample of 13,255 children and youth aged 6-17 years were used for data analysis. A previously validated questionnaire was used to assess PA prevalence. Logistic regression was conducted to examine the relationships of socio-demographic factors, and participation in different PA domains with overall PA.

Results

Only 23.4% of Thai children and youth met recommended levels of PA and there were large gender and regional differences. PA levels generally declined with age, although the level observed in the 10-13 year group was slightly higher than other year groups. A majority of children and youth engaged in a large number of different activities across PA domains. Sex, age, BMI, geographical regions, organized sports, participation in sport and recreational activities were significant predictors of meeting the global PA guidelines, whereas participation in physical education, active transport, and the number of screen time activities had no association. Girls were less likely to achieve sufficient PA levels (OR = 0.49, 95%CI; 0.45-0.54, p < 0.001), as were obese children (OR = 0.78, 95%CI; 0.64-0.94, p = 0.01), children living in the West (OR = 0.47, 95%CI; 0.38-0.59, p < 0.001), and those who did no participation in organized sports and sport/exercise activities, or minimal participation (1-2 activities) in recreational activities (OR = 0.79, 95%CI; 0.68-0.90, p < 0.001).

Conclusions

The prevalence estimate of meeting the recommended guideline of sufficient PA in Thai children and youth is low, despite the high levels of engagement in a large number of PA. The results indicate that policy and interventions aimed at increasing PA are needed with special attention required to address specific groups less likely to meet the PA guideline. Strategies to promote a large volume of participation in all possible types of PA as part of Thai children and youth’s daily life should be considered.

Age, period and cohort effects and the predictors of physical activity and sedentary behaviour among Chinese children, from 2004 to 2011

BACKGROUND

Very few studies have explored the effects of age, time period, and cohort in association with biological, behavioral, economic, and environmental factors predictors on physical activity (PA) and sedentary behaviour (SB) among Chinese children.

METHODS

We used data from a cohort study of the China Health and Nutrition Survey (CHNS) between 2004 and 2011 (2004, 2006, 2009 and 2011). The outcomes of interest were metabolic equivalent of task (MET) hours per week from both active and sedentary activities. Age, gender, individual characteristics, household size, asset ownership, and urbanisation were included as covariates. Age, period and cohort effects analyses for PA and SB of children (6-17 y, n = 3528) was conducted to explicitly assess differences in PA and SB due to age vs. period effects, and implicitly assess differences by cohorts due to the period-specific experiences across individuals of varying ages.

RESULTS

The mean age of the sample in each time point fluctuated from 12.6 to 11.3 years and PA slightly decreased from 50.0 ± 63.2 MET hours per week (MET-hr./wk) in 2004 to 47.1 ± 54.9 MET-hr./wk. in 2011. However, SB increased from 31.8 ± 22.0 MET-hr./wk. to 37.6 ± 22.2 MET-hr./wk. Girls had lower PA and higher SB levels than boys. Controlling for age effects, marginal period effects on PA were observed in some survey years. Higher levels of urbanisation and number of household computers served as negative and positive predictors for PA and SB, respectively. Higher household income was a positive predictor of SB. Surprisingly, bigger household size was the only negative predictor of SB (P < 0.05).

CONCLUSIONS

This longitudinal study followed a large cohort of children over a significant period of their childhood. We observed potential age and secular trends in PA levels. Higher community urbanisation and number of home computers were associated with both PA and SB levels. Larger household size was the only factor that was negatively associated with SB. These findings shed light on health policy and preventative health strategies for China and other countries that are now facing similar public health challenges.

Factors of physical activity among Chinese children and adolescents: a systematic review

Background

Lack of physical activity is a growing problem in China, due to the fast economic development and changing living environment over the past two decades. The aim of this review is to summarize the factors related to physical activity in Chinese children and adolescents during this distinct period of development.

Methods

A systematic search was finished on Jan 10^th, 2017, and identified 2200 hits through PubMed and Web of Science. English-language published studies were included if they reported statistical associations between factors and physical activity. Adapted criteria from the Strengthening The Reporting of OBservational studies in Epidemiology (STROBE) statement and evaluation of the quality of prognosis studies in systematic reviews (QUIPS) were used to assess the risk of bias of the included studies. Related factors that were reported in at least three studies were summarized separately for children and adolescents using a semi-quantitative method.

Results

Forty two papers (published 2002–2016) were included. Most designs were cross-sectional (79%), and most studies used questionnaires to assess physical activity. Sample size was above 1000 in 18 papers (43%). Thirty seven studies (88%) showed acceptable quality by methodological quality assessment. Most studies reported a low level of physical activity. Boys were consistently more active than girls, the parental physical activity was positively associated with children and adolescents’ physical activity, children in suburban/rural regions showed less activity than in urban regions, and, specifically in adolescents, self-efficacy was positively associated with physical activity. Family socioeconomic status and parental education were not associated with physical activity in children and adolescents.

Conclusions

The studies included in this review were large but mostly of low quality in terms of study design (cross-sectional) and methods (questionnaires). Parental physical activity and self-efficacy are promising targets for future physical activity promotion programmes. The low level of physical activity raises concern, especially in suburban/rural regions. Future research is required to enhance our understanding of other influences, such as the physical environment, especially in early childhood.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0486-y) contains supplementary material, which is available to authorized users.

Using the self-determination theory to understand Chinese adolescent leisure-time physical activity

PURPOSES

This study applies the self-determination theory (SDT) to test the hypothesized relationships among perceived autonomy support from parents, physical education (PE) teachers, and peers, the fulfilment of psychological needs (i.e., autonomy, competence, and relatedness), autonomous motivation, and leisure-time physical activity of Chinese adolescents.

METHOD

There are 255 grade six to eight student participants from four middle schools around Shanghai, China included in this study. An accelerometer was used to measure the moderate-to-vigorous physical activity (MVPA). The participants completed the questionnaires regarding SDT variables. The structural equation modelling was applied to examine the hypothesized relationships among the study variables.

RESULTS

The model of hypothesized relationships demonstrated a good fit with the data [X² = 20.84, df = 9, P = .01; CFI = 0.98; IFI = 0.98; SRMR = 0.04; RMSEA = 0.05]. The findings revealed that autonomy support from parents, PE teachers, and peers foster social conditions in which the three basic psychological needs can be met. In turn, autonomy, competence, and relatedness are positively associated with autonomous motivation for MVPA. The autonomous motivation positively relates to the MVPA time of adolescents. The three psychological needs partially mediate the influence of autonomy support from parents (β = 0.18, P < .01; Bootstrap 95% CI = 0.06-0.33) and teachers (β = 0.17, P < .01; Bootstrap 95% CI = 0.03-0.26) in the autonomous motivation.

CONCLUSION

In conclusion, these findings support the applicability of SDT in understanding and promoting physical activity of Chinese adolescents.

Excessive homework, inadequate sleep, physical inactivity and screen viewing time are major contributors to high paediatric obesity

Aim

This study examined the relationships between energy balance‐related behaviours (EBRBs) outside school hours and obesity in Chinese primary school students. We also explored the influence of gender on those relationships.

Methods

The study sample was a cross‐sectional cohort of 5032 Chinese children who were enrolled in grades 1–6 in primary schools in five Chinese cities and whose mean ages ranged from seven years and three months to 11.9 years. The children's parents completed a survey on their child's height, weight and EBRBs outside school hours.

Results

The response rate was 97%, and the reported rates of overweight and obesity were 13.6% and 13.8%, respectively. The obesity rates were higher in boys and lower grade children. Most EBRBs varied between boys and girls and with increased grade levels. The amount of time spent on academic‐related activities, screen viewing, outdoor activities and sleep was mostly associated with obesity on weekdays and varied by gender.

Conclusion

Rate of obesity was alarmingly high in the primary school Chinese children in this cohort, especially in younger children. Excessive time spent on academic‐related activities outside school hours, inadequate sleep, physical inactivity and higher levels of screen viewing were major contributors to obesity in these Chinese children.

Psychological Correlates of Self-Reported and Objectively Measured Physical Activity among Chinese Children-Psychological Correlates of PA

This study aimed to explore the associations among psychological correlates and physical activity (PA) in Chinese children and to further examine whether these associations varied by different PA measures. PA self-efficacy, motivation, and preference were reported in 449 8–13-year-old Chinese children (252 males). Moderate- to vigorous- intensity PA (MVPA) was measured by the Physical Activity Questionnaire for Older Children (PAQ-C) and with an ActiGraph GT3X accelerometer. Correlations and hierarchical regressions were performed to explore their associations. The study psychological variables were all positively related to PAQ-C and objective MVPA (r: 0.22–0.63). The associations with PAQ-C were all substantially stronger than those with accelerometry. Beyond the explained variance accounted for by demographics and social desirability, the addition of the psychological correlates accounted for 45% of the variance of the PAQ-C score, while only 13% for accelerometry-based MVPA. The associations of specific variables with the PAQ-C score (age, PA self-efficacy, autonomous motivation and preference) were somewhat different from those associated with objective MVPA (PA self-efficacy, autonomous motivation, and negatively associated with female gender). This study demonstrated the importance of self-efficacy and autonomous motivation in association with PA and indicated the difference in level of their associations with different PA measures.

Seasonal changes in objectively measured sedentary behavior and physical activity in Japanese primary school children

BACKGROUND

The recent prevalence of obesity in Japanese children is much higher compared to 1980. The present study compared daily sedentary behavior (SB) and physical activity (PA) between the school year and summer vacation in Japanese primary school children.

METHODS

Participants were 98 Japanese boys (8.9 ± 1.8 years at baseline) and 111 girls (9.1 ± 1.8 years). SB and PA were measured in May (school term) and July/August (summer vacation), 2011. SB and PA were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare) for 7 consecutive days. The average number of minutes spent in SB (no more than 1.5 metabolic equivalents (METs)), light intensity activity (LPA; more than 1.5 to less than 3.0 METs) and moderate-to-vigorous physical activity (MVPA; 3.0 METs or more), and step counts were calculated for each individual. Moreover, the determinants/moderators of changes in SB and PA were examined.

RESULTS

Daily SB was significantly higher in the summer vacation than in the school year for both boys and girls (p < 0.05). Ambulatory and total LPA and MVPA, non-ambulatory LPA and step counts were lower in summer vacation in both genders (p < 0.001). Moreover, non-ambulatory MVPA was significantly lower in the summer vacation than in the school year for girls (p < 0.001). The decrease in non-ambulatory MVPA in boys and increase in SB in girls were significantly lower in those who participated in sports compared to those who did not (p < 0.040 or p < 0.033). The change in SB for boys was significantly associated with having a TV in the bedroom (p < 0.022).

CONCLUSIONS

These findings show that primary school children in Japan are less active in the summer vacation, as indicated by both higher SB and lower LPA and ambulatory MVPA in both genders. Moreover, the seasonal change in non-ambulatory MVPA for Japanese children was affected by gender. This study also suggests that sports participation and bedroom TV ownership may moderate seasonal changes in PA and SB. The results emphasize the need to take summer vacation into account when planning interventions aimed at decreasing SB or increasing PA in Japanese children.

The prevalence of obesity and influence of early life and behavioral factors on obesity in Chinese children in Guangzhou

BACKGROUND

Childhood obesity has become a public health concern in many countries. In Southern China, the prevalence of childhood obesity increased from 6.2 to 7.5 % between 2007 and 2011. This study aimed to report the current prevalence of overweight and obesity, analyzed the early life and behavioral determinants of obesity, and investigated the weight-loss practices among Chinese children in Guangzhou.

METHODS

Three thousand seven hundred sixty-six primary school students aged 7-12 years were recruited in Guangzhou, China in 2013. Questionnaires were used to assess (1) early life factors: birth weight, delivery mode, gestational age and feeding patterns; (2) behavioral factors: dietary intake, eating speed, sedentary time, physical activities and sleep duration; and (3) weight-loss practices: improving diet, increasing exercise, taking weight-loss drugs and undergoing a diet. The criteria of Working Group of Obesity in China were applied to classify overweight and obesity based on measured weight and height. Multivariable logistic regression analyses were performed to examine the determinants of overweight/obesity and adoption of weight-loss practices.

RESULTS

The prevalence of childhood overweight and obesity were 11.2 and 10.0 %, respectively. High birth weight (≥4.0 kg versus 2.5 ~ 4.0 kg, odd ratio [OR]: 2.34; 95 % confidence interval [CI]: 1.53-3.58), sugar-sweetened beverages (SSBs) intake (OR: 1.39; 95 % CI: 1.05-1.85), vegetable intake (OR: 1.12; 95 % CI: 1.01-1.24), and doing homework (OR: 1.24; 95 % CI: 1.08-1.43) were positively associated with obesity. Eating speed faster than peers was positively associated with obesity and yielded the highest OR (versus "as fast as peers", OR: 3.18; 95 % CI: 2.28-4.44). Approximately 57, 81 and 87 % of normal-weight, overweight and obese children, respectively, reported weight-loss practices. Self-perception of weight status presented as the strongest determinant for weight-loss practices.

CONCLUSIONS

The prevalence of overweight and obesity were high in Chinese children in Guangzhou, and both were higher than previous level in 2011. Further research should address the unhealthy dietary (e.g. SSBs intake, fast eating speed) and sedentary behaviors (e.g. doing homework) of these children. Moreover, an accurate perception of body weight can help promote the adoption of weight-loss practices in overweight and obese children.

Systematic review of sedentary behaviour and health indicators in school-aged children and youth: an update

This systematic review is an update examining the relationships between objectively and subjectively measured sedentary behaviour and health indicators in children and youth aged 5–17 years. EMBASE, PsycINFO, and Medline were searched in December 2014, and date limits were imposed (≥February 2010). Included studies were peer-reviewed and met the a priori-determined population (apparently healthy children and youth, mean age: 5–17 years), intervention (durations, patterns, and types of sedentary behaviours), comparator (various durations, patterns, and types of sedentary behaviours), and outcome (critical: body composition, metabolic syndrome/cardiovascular disease risk factors, behavioural conduct/pro-social behaviour, academic achievement; important: fitness, self-esteem) study criteria. Quality of evidence by outcome was assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework. Due to heterogeneity, a narrative analysis was conducted. A total of 235 studies (194 unique samples) were included representing 1 657 064 unique participants from 71 different countries. Higher durations/frequencies of screen time and television (TV) viewing were associated with unfavourable body composition. Higher duration/frequency of TV viewing was also associated with higher clustered cardiometabolic risk scores. Higher durations of TV viewing and video game use were associated with unfavourable behavioural conduct/pro-social behaviour. Higher durations of reading and doing homework were associated with higher academic achievement. Higher duration of screen time was associated with lower fitness. Higher durations of screen time and computer use were associated with lower self-esteem. Evidence ranged from “very low” to “moderate” quality. Higher quality studies using reliable and valid sedentary behaviour measures should confirm this largely observational evidence.

Association between Family Structure and Physical Activity of Chinese Adolescents

Background. This study examines the association between family structure and moderate-to-vigorous physical activity (MVPA) of adolescents in China. Methods. The participants included 612 adolescents (317 boys and 295 girls) from Shanghai with ages ranging from 10 to 16 years. Accelerometers were used to measure the duration of MVPA of adolescents, and questionnaires on family structure were completed by the parents of these adolescents. Results. Findings suggested that family structure significantly increased the likelihood of adolescents engaging in physical activity (PA) and explained 6% of MPVA variance. Adolescents living in single-parent households and step families were more physically active than those living in two-parent homes and with biological parents, respectively. However, adolescents residing with grandparents were less active than those living with neither grandparent. No significant difference was found in MVPA time between adolescents living with one sibling and those without siblings. Conclusion. Family environment may be considered in the development of PA interventions and policies, and adolescents living with their grandparents may be targeted in PA promotion.

Correlates of children's compliance with moderate-to-vigorous physical activity recommendations: a multilevel analysis

This study aimed to investigate the association between individual and school characteristics associated with the number of school days children comply with moderate-to-vigorous physical activity (MVPA) recommendations. Sample comprises 612 Portuguese children, aged 9-11 years, from 23 schools. Time spent in MVPA was measured by accelerometry, while individual-level correlates were obtained by anthropometry and questionnaires. School-level variables were collected by questionnaire, and accelerometer wear time and season were also considered. Maximum likelihood estimates of model parameters were obtained via a multilevel analysis with children as level-1, and school as level-2. Children who spent more time in sedentary activities and girls were less likely to comply with MVPA/daily. More mature children and those who use active transportation to school were more likely to attain the PA recommendation. Furthermore, greater accelerometer wear time and spring season increased the chance to achieve the recommended MVPA. In terms of school-level correlates, a greater number of available facilities was negatively associated with children MVPA compliance. Given the set of variables, our results showed that individual characteristics seem to be more relevant for children's compliance rates with PA/day than school context variables, which should be taken into account in the implementation of school policies and practices.

Development of a Dietary Index to Assess Overall Diet Quality for Chinese School-Aged Children: The Chinese Children Dietary Index

BACKGROUND

A composite measure of diet quality is preferable to an index of nutrients, food groups, or health-promoting behaviors in dietary assessment. However, to date, such a tool for Chinese children is lacking.

OBJECTIVE

Based on the current Chinese Dietary Guidelines and Dietary Reference Intakes, a dietary index for Chinese school-aged children, the Chinese Children Dietary Index was developed to assess overall diet quality among children in South China.

DESIGN

Dietary data were recorded using 24-hour recalls among 1,719 children aged 7 to 15 years between March and June 2013. Inactivity data and sociodemographic information were also collected. The Chinese Children Dietary Index included 16 components, which incorporated nutrients, foods/food groups, and health-promoting behaviors. The range of possible Chinese Children Dietary Index scores was 0 to 160, with a higher score indicating better diet quality.

STATISTICAL ANALYSIS PERFORMED

Pearson/Spearman correlation was used to assess relative validity using correlations between total Chinese Children Dietary Index score and age, body mass index (BMI; calculated as kg/m(2)), inactivity, whole-grain intake, frequency of fried-foods intake, nutrient adequacy ratios for energy intake and 12 nutrients not included in the Chinese Children Dietary Index, and the mean adequacy ratio. Finally, a stepwise multiple regression analysis was performed to indicate the factors correlated with Chinese Children Dietary Index.

RESULTS

Mean Chinese Children Dietary Index score of this sample was 88.1 points (range=34.2 to 137.8), the Chinese Children Dietary Index score of girls was higher than that of boys and decreased with higher age. Children with higher Chinese Children Dietary Index had lower body mass index and spent less time being inactive. Positive associations were observed between Chinese Children Dietary Index and the majority of nutrient adequacy ratios and the mean adequacy ratio. Age, paternal educational level, and family size were correlated with Chinese Children Dietary Index.

CONCLUSIONS

The Chinese Children Dietary Index successfully differentiated diets and, therefore, it can be used to rank-order overall diet quality among Chinese children. As the results showed, diet quality among Chinese children needs to be improved, especially in adolescents.

Gender and grade differences in objectively measured physical activity and sedentary behavior patterns among Japanese children and adolescents: a cross-sectional study

Background

Physical activity levels in childhood have decreased, making the promotion of children’s physical activity an important issue. The present study examined gender and grade differences in objectively measured sedentary behavior, physical activity, and physical activity guideline attainment among Japanese children and adolescents.

Methods

In total, 329 boys and 362 girls age 3–15 years completed the survey. School grade, gender, height, and weight were collected by questionnaires and physical activity objectively measured using an accelerometer (Lifecorder Suzuken Co.). Physical activity level (in MET) was classified as sedentary (<1.5), light (≥1.5 to <3), moderate (≥3 to <6), or vigorous (≥6). Continuous zero accelerometer counts for ≥20 min were censored and a valid accelerometry study required at least 3 days (2 weekdays and 1 weekend day) with > 600 min/day total wear time. Two-way analysis of covariance and logistic regression analyses, adjusted for weight status and accelerometer wear time, were used to examine gender and grade differences in physical activity variables and the likelihood of physical activity guideline attainment by gender and grade level.

Results

Participants were sedentary 441.4 (SD, 140.1) min/day or 53.7 % of the average daily accelerometer wear time of 811.2 (118.7) min, engaged in light physical activity 307.1 (70.0) min or 38.4 % of wear time, moderate physical activity 34.6 (14.8) min (4.3 %), vigorous physical activity 28.3 (19.1) min (3.6 %), and took 12462.6 (4452.5) steps/day. Boys were more physically active and took more steps/day than girls. Students in higher grades were less active than those in lower grades. Boys were significantly more likely to meet physical activity guidelines than girls (OR: 2.07, 95 % CI: 1.45–2.96). Preschoolers (6.66, 4.01–11.06), lower-grade elementary school students (17.11, 8.80–33.27), and higher-grade elementary school students (7.49, 4.71–11.92) were more likely to meet guidelines than junior high school students.

Conclusions

Boys and lower-grade students engaged in more physical activity and were more likely to attain guidelines than girls and higher-grade students. These findings highlight the need for effective and sustainable strategies to promote physical activity in Japanese school children.

Using Theory of Planned Behavior to Predict the Physical Activity of Children: Probing Gender Differences

Objectives. The primary objective of this study was to use the theory of planned behavior (TPB) to examine the association between TPB variables and the moderate-to-vigorous physical activity (MVPA) of children in Shanghai, China. Gender differences were also explored. Methods. The participants were 353 children (180 boys and 173 girls) aged 9 to 13 years from three primary schools in Shanghai. Accelerometers were used to measure the MVPA duration of the children. Questionnaires that focused on attitude, subjective norms, and perceived behavioral control (PBC) related to MVPA engagement were completed by the participants. Results. Regression analyses revealed that intention, and not PBC, accounted for 9% of the variance in MVPA. Meanwhile, attitude and PBC explained 33% of the variance in intentions to engage in MVPA. In terms of gender differences, TPB performed better in the physical activity (PA) domain for boys than for girls. Furthermore, attitude and PBC were significantly associated with intention among boys, whereas only PBC was significantly related to intention among girls. Conclusion. Practitioners should consider tailoring intervention to address gender differences to increase leisure-time PA participation of children.

Understanding trends in blood pressure and their associations with body mass index in Chinese children, from 1985 to 2010: a cross-sectional observational study

OBJECTIVE

Understanding trends in blood pressure (BP) in childhood is crucial to addressing and reducing the burden of adulthood hypertension and associated mortality in the future. In view of growing obesity in Chinese children, we sought to investigate the trends in BP and the influence of body mass index (BMI) on them.

DESIGN, SETTING AND PARTICIPANTS

We included 1,010,153 children aged 8-17 years, with completed records from a large national successive cross-sectional survey, the Chinese National Survey on Students' Constitution and Health, between 1985 and 2010.

MAIN OUTCOME MEASUREMENTS

BP was measured according to the recommendation of the National High Blood Pressure Education Program Working Group, and the elevated BP was based on sex-, age- and height-specific 95th centile of the recommendation.

RESULTS

The adjusted mean systolic BP in boys and girls decreased by 3.9 and 5.6 mm Hg between 1985 and 2005, and increased by 1.3 and 1.0 mm Hg between 2005 and 2010, respectively. Corresponding adjusted prevalence of elevated systolic BP in boys and girls declined from 5.1% and 5.5% to 3.5% and 2.5% between 1985 and 2005, and increased to 4.9% and 3.5% in 2010, respectively. Adjusted mean BMI of boys and girls in 2010 was 2.0 and 1.2 kg/m(2) higher than those in 1985, respectively. The prevalence of obesity rose from 0% to 3.4% in boys and 0.9% in girls. Further adjusting for BMI did not change these trends in systolic BP. A similar pattern was also observed in diastolic BP.

CONCLUSIONS

After declining for 20 years, BP levels in Chinese children started to climb upwards. These trends in BP cannot be fully explained by BMI. The investigation of other determinants of BP may provide additional opportunity to curb the current upward BP trend in Chinese children.