With increases in inactive lifestyles and mounting pressure for academic excellence in Chinese younger populations, lack of physical activity and increased prevalence of obesity have become a major public health concern in China. The purpose of this study is to provide updated estimates on the prevalence of meeting moderate-vigorous physical activity (MVPA) and screen viewing time guidelines, and overweight and obesity among Chinese school-aged children and adolescents, with a secondary aim examining variations in prevalence by sex, grade groupings, and residential location. The study sample came from the 2017 Physical Activity and Fitness in China—The Youth Study, a cross-sectional and national survey of 131,859 students (aged 7 to 19 years) from 986 public schools in China. Measures of MVPA, screen viewing time, and age- and sex-specific overweight and obese body mass index were used to calculate national prevalence estimates of Chinese school-aged children and adolescents. In 2017, 34.1% (95% confidence interval [CI], 34.09–34.11%) of children and adolescents met MVPA guidelines and 65.4% (95% CI, 65.39–65.41%) adhered to screen viewing time guidelines. The prevalence of overweight and obesity was 15.1% (95% CI, 15.09–15.11%) and 10.7% (95% CI, 10.69–10.71%), respectively. Prevalence estimates differed by sex (boys, girls), grade grouping (primary schools, junior middle schools, junior high schools), and residential location (rural, urban). There remains a low prevalence of meeting MVPA guidelines and high prevalence of overweight and obesity in Chinese school-aged children and adolescents. Future efforts should focus on monitoring the trend of these behavioral and health risk factors to inform school policies and programs aimed at increasing physical activity and reducing and preventing obesity in younger populations in China.

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. 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. 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). 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.

Meeting 24-h movement guidelines by children and adolescents has been associated with improved indicators of health, although it has been under-studied in China. Hence, this study aimed to investigate the prevalence of meeting the 24-h movement guidelines, its correlates, and its relationships with body mass index in children and adolescents in China. Cross-sectional data from the 2017 Youth Study in China of 114,072 children and adolescents (mean age = 13.75 years, 49.18% boys) were used. Meeting 24-h movement guidelines (≥60 min of daily moderate-to-vigorous physical activity, ≤2 h of daily leisure screen time, 9-11 h and 8-10 h nightly sleep duration for 6-13-year-olds and 14-17-year-olds, respectively) and height and weight of all participants were assessed. The prevalence of meeting the 24-h movement guidelines and World Health Organization weight status categories were determined. Generalized linear models were used to determine the correlates of meeting the 24-h movement guidelines and the relationships of meeting the 24-h movement guidelines with overweight (OW) and obesity (OB). Only 5.12% of Chinese children and adolescents met the 24-h movement guidelines, and 22.44% were classified as OW/OB. Older children and adolescents were less likely to meet the 24-h movement guidelines. Parental education level and family income were positively related to meeting the 24-h movement guidelines. Children and adolescents meeting the 24-h movement guidelines showed lower odds ratios for OW/OB. Compared with participants meeting the 24-h movement guidelines, boys in 4th-6th grades met none of the recommendations (OR = 1.22, 95%CI: 1.06-1.40), met the screen time recommendation only (OR = 1.13, 95%CI: 1.01-1.28), met the nightly sleep duration recommendation only (OR = 1.14, 95%CI: 1.03-1.28), and had significantly higher odds ratios for OW/OB. Similar trends were observed for girls in 4th-6th grades: meeting none of the guidelines (OR = 1.35, 95%CI: 1.14-1.59), meeting sleep duration guidelines only (OR = 1.23, 95%CI: 1.08-1.39), and meeting moderate-to-vigorous physical activity + nightly sleep duration guidelines (OR = 1.24, 95%CI: 1.01-1.54). For girls in 7th-9th grades, the following trend was observed: meeting none of the guidelines (OR = 1.30, 95%CI: 1.01-1.67). Very few Chinese children and adolescents met the 24-h movement guidelines. Age (negatively correlated), parental education level, and family income (both positively correlated) were correlates of meeting the 24-h movement guidelines. Children and adolescents meeting the 24-h movement guidelines were more likely to have lower risks for OW/OB, especially in the youngest age group (Grades 4-6); and girls in the middle age group (Grades 7-9) were also more likely to have lower risks for OW/OB. Further research studies should explore additional correlates and determinants for meeting the 24-h movement guidelines. Also, future studies should use longitudinal or interventional designs to determine the relationships between meeting the 24-h movement guidelines and OW/OB and other health indicators, while taking sex and age differences into account.

Vitamin D may play a role in skeletal muscle because of the discovery of VDR in skeletal muscle. However, vitamin D deficiency is a global problem, including athletes. Studies examining the effect of vitamin D supplementation on muscle function in athletes have inconsistent results. Therefore, we aimed to quantitatively summarize the evidence for the effect of vitamin D supplementation on skeletal muscle strength and explosive power of athletes using a meta-analysis. PubMed, EMBASE, Cochrane Library, and Web of Science were searched for studies to identify randomized controlled trials or controlled trials meeting the inclusion criteria. By a meta-analysis, effect sizes (standardized mean differences, SMD) with 95% confidence intervals (CI) was calculated to compare reported outcomes across studies, I² index was used to assessing heterogeneity, and heterogeneity factors were identified by regression analysis. The potential publication and sensitivity analyses were also assessed. Eight RCTs involving 284 athletes were included. The protocols used to evaluate the muscle strength of athletes were inconsistent across the included studies, and muscle explosive power was assessed via vertical jump tests. The results indicated that vitamin D supplementation had no impact on overall muscle strength outcomes (SMD 0.05, 95% CI: -0.39 to 0.48, p = 0.84). In subgroup analysis, vitamin D supplementation had an effect on lower-limb muscle strength (SMD 0.55, 95% CI:0.12 to 0.98, p = 0.01) but not upper-limb muscle strength (SMD -0.19, 95% CI:-0.73 to 0.36, p = 0.50) or muscle explosive power (SMD 0.05, 95% CI:-0.24 to 0.34, p = 0.73). Vitamin D supplementation was more effective for athletes trained indoors (SMD 0.48, 95% CI:0.06 to 0.90, p = 0.02). Vitamin D supplementation positively affected lower limb muscle strength in athletes, but not upper limb muscle strength or muscle power. Different muscle groups and functions may respond differently to vitamin D supplementation. Additional studies should focus on determining the appropriate vitamin D supplementation methods and optimal serum 25(OH)D levels for athletes. The protocol for our study is registered in the international prospective register of systematic reviews (PROSPERO registration number CRD42016045872).

Background: Internationally comparable evidence is important to advocate for young people’s physical activity. The aim of this article is to present the inaugural Shanghai (China) Report Card on Physical Activity for Children and Youth.Methods: Since no national data are available, the working group developed the survey questionnaire and carried out the school surveys for students (n = 71,404), parents (n = 70,346), and school administrators and teachers (n = 1398). The grades of 9 report card indicators were assigned in accordance with the survey results against a defined benchmark: A is 81% to 100%; B is 61% to 80%; C is 41% to 60%, D is 21% to 40%; F is 0% to 20%.Results: The 9 indicators were graded as follows: Overall Physical Activity Levels (F), Organized Sport Participation (F), Active Play (D-), Active Transportation (C-), Sedentary Behavior (F), Family and Peers (B), School (B+), Community and the Built Environment (D+), and Government (D).Conclusions: Levels of physical activity and sedentary behavior were low and below the respective recommended guidelines. Interventions and policies at the community level should be encouraged to promote physical activity and reduce sedentary behavior. Future national surveys should be encouraged to strengthen Shanghai’s Report Card on Physical Activity for Children and Youth.

This study aimed to determine if combined exercise intervention improves physical performance and gait joint-kinematics including the joint angle and dynamic range of motion (ROM) related to the risk of falling in community-dwelling elderly women. A 12-week combined exercise intervention program with extra emphasis on balance, muscle strength, and walking ability was designed to improve physical performance and gait. Twenty participants attended approximately two-hour exercise sessions twice weekly for 12 weeks. Participants underwent a physical performance battery, including static balance, sit and reach, whole body reaction time, 10 m obstacle walk, 10 m maximal walk, 30-second chair stand, to determine a physical performance score, and received quantitative gait kinematics measurements at baseline and in 12 weeks. Significant lower extremity strength improvement 13.5% (p<.001) was observed, which was accompanied by significant decreases in time of the 10 m obstacle walk (p<.05) and whole body reaction time (p<.001) in this study. However, no significant differences were seen for static balance and flexibility from baseline. For gait kinematics, in the mid-swing phase, knee and hip joint angle changed toward flexion (p<.01, p<.05, respectively). Ankle dynamic ROM significantly increased (p<.05) following exercise intervention. The plantar flexion angle of the ankle in the toe-off phase was increased significantly (p<.01). However, other gait parameters were not significantly different from baseline. These findings from the present investigation provide evidence of significant improvements in physical performance related to the risk factors of falling and safe gait strategy with a combined exercise intervention program in community-dwelling elderly women. The results suggest this exercise intervention could be an effective approach to ameliorate the risk factors for falls and to promote safer locomotion in elderly community-dwelling women.