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Jason A. Mendoza, David Cowan and Yan Liu

Background:

Few reports examined long term predictors of children’s active commuting to school (walking or cycling to school, ACS).

Purpose:

To identify predictors of ACS over 1 school year among a sample of children with relatively high rates of ACS.

Methods:

Parents were surveyed in September 2010 (Time 1) and April 2011 (Time 2). The dependent variable was children’s commuting mode to school (active versus passive). Independent variables included: 1) parents’ outcome expectations (from Social Cognitive Theory: the expected risks/benefits for their child doing ACS), 2) distance to school, 3) participation in an adult-led walk to school group, 4) temperature, and 5) child demographics. Generalized mixed-models estimated odds ratios for ACS (n = 369 or 49.7% of Time 1 respondents).

Results:

Males (OR = 2.59, 95% CI [1.57–4.30]), adult-led walk to school group participation (OR = 1.80, 95% CI [1.14–2.86]), parents’ outcome expectations (OR = 1.26, 95% CI [1.14–1.39]), temperature (OR = 1.03, 95% CI [1.01–1.07), distance to school (OR = 0.23, 95% CI [0.14–0.37]), and Latino ethnicity (OR = 0.28, 95% CI [0.12–0.65]) were associated with ACS.

Conclusions:

Programs and policies sensitive to parents’ concerns (eg, adult-led walk to school groups) and targeting Latinos and girls appear promising for increasing ACS.

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Yu-Qian Liu, Yan-Zhong Chang, Bin Zhao, Hai-Tao Wang and Xiang-Lin Duan

Some athletes are diagnosed as suffering from sports anemia because of iron deficiency, but the regulatory mechanism remains poorly understood. It is reported that hepcidin may provide a way to illuminate the regulatory mechanism of exercise-associated anemia. Here the authors investigate the hepcidin-involved iron absorption in exercise-associated anemia. Twelve male Wistar rats (300 ± 10 g) were randomly divided into 2 groups, 6 in a control group (CG) and 6 in an exercise group (EG, 5 wk treadmill exercise of different intensities with progressive loading). Serum samples were analyzed for circulating levels of IL-6 by means of enzyme-linked immunosorbent assay (ELISA). The expression of hepatic hepcidin mRNA was examined by real-time polymerase chain reaction analysis. The protein levels of divalent metal transporter 1 (DMT1), ferroportin1 (FPN1), and heme-carrier protein 1 (HCP1) of duodenum epithelium were examined by Western blot. The results showed that the amount of iron and ferritin in serum were lower in EG than in CG (p < .05). The levels of IL-6 and white blood cells were greater in EG than in CG (p < .01). The expression of DMT1, HCP1, and FPN1 was significantly lower in EG than in CG (p < .01). The mRNA expressions of hepatic hepcidin and hemojuvelin in skeletal muscle were remarkably higher in EG than in CG. The data indicated that inflammation was induced by strenuous exercise, and as a result, the transcriptional level of the hepatic hepcidin gene was increased, which further inhibited the expression of iron-absorption proteins and led to exercise-associated anemia.

Open access

Maurice R. Puyau, Anne L. Adolph, Yan Liu, Theresa A. Wilson, Issa F. Zakeri and Nancy F. Butte

Background:

The absolute energy cost of activities in children increases with age due to greater muscle mass and physical capability associated with growth and developmental maturation; however, there is a paucity of data in preschool-aged children. Study aims were 1) to describe absolute and relative energy cost of common activities of preschool-aged children in terms of VO2, energy expenditure (kilocalories per minute) and child-specific metabolic equivalents (METs) measured by room calorimetry for use in the Youth Compendium of Physical Activity, and 2) to predict METs from age, sex and heart rate (HR).

Methods:

Energy expenditure (EE), oxygen consumption (VO2), HR, and child-METs of 13 structured activities were measured by room respiration calorimetry in 119 healthy children, ages 3 to 5 years.

Results:

EE, VO2, HR, and child-METs are presented for 13 structured activities ranging from sleeping, sedentary, low-, moderate- to high-active. A significant curvilinear relationship was observed between child-METs and HR (r 2 = .85; P = .001).

Conclusion:

Age-specific child METs for 13 structured activities in preschool-aged children will be useful to extend the Youth Compendium of Physical Activity for research purposes and practical applications. HR may serve as an objective measure of MET intensity in preschool-aged children.

Open access

Yang Liu, Yan Tang, Zhen-Bo Cao, Pei-Jie Chen, Jia-Lin Zhang, Zheng Zhu, Jie Zhuang, Yang Yang and Yue-Ying Hu

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.

Open access

Yang Liu, Yan Tang, Zhen-Bo Cao, Jie Zhuang, Zheng Zhu, Xue-Ping Wu, Li-Juan Wang, Yu-Jun Cai, Jia-Lin Zhang and Pei-Jie Chen

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Jie Liang, Shuang-Shuang Tian, Nan Qiao, Cong Wang, Jian-Jun Huang, Chen-Ming Sun, Hai-Xia Zhang, Yan Cui, Hui Wang, Xiao-Meng Liu, Shu-Hong Xu, Hongwei Guan and Tong Wang

Objective:

This study aimed to investigate the relationship between metabolic syndrome (MetS) and physical activity (PA) in different domains among male coal miners of Shanxi Province in China.

Method:

The study was conducted from July 2013 to December 2013. A two-stage stratified cluster sampling method was used. Data regarding the general information of participants were collected by well-trained interviewers. MetS was defined according to IDF criteria. Self-reported PA was obtained with the IPAQ and categorized into three tertiles of intensity levels across occupation, transportation, household, and leisure-time domains. Univariate and multiple logistic regression analysis were applied to compute the odds ratios and their 95% confidence interval (CI).

Results:

A total of 3076 males aged 18–65 years old were recruited in this cross-sectional study. The prevalence of MetS was 40.5% in the study subjects. The percentages of vigorous-intensity PA in MetS and non-MetS groups were 70.07% and 62.92%, respectively. Participants spent most of their time on occupation (2034 MET-min/w) and transportation (693MET-min/w) domains. Higher-intensity levels in occupation domains were significantly associated with lower risk of MetS (OR: 0.759, 95% CI: 0.633–0.911; OR: 0.627, 95% CI: 0.516–0.762).

Conclusions:

Across four types of workers, the relationships between PA domains and MetS were different. For underground and underground auxiliary workers, the negative relationship was found between occupation PA and MetS. For office workers, the negative relationship was found between household PA and MetS. For ground workers, only leisure-time PA had positively related to MetS.