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To determine whether interrupting prolonged sitting with three different activity breaks has both acute and chronic effects on postprandial lipid metabolism immediately after the activity‐break period and on the following day, this study is a secondary analysis of an experimental research, which included 16 sedentary healthy adults (7 men, 24 ± 3 years, BMI 22.2 ± 2.3 kg/m2) who completed four 26‐h laboratory trials. Participants spent 22.5 hours in a whole room calorimeter for testing energy expenditure (EE), including a 9‐h activity‐break period: (a) 9‐h prolonged sitting (SIT); (b) 3 minutes of brisk walking (60% VO2max) in between every 30‐min sitting bout (WALK3), (c) 5 minutes every 45‐min (WALK5), and (d) 8 minutes every 60‐min (WALK8). Total area under the curve (tAUC) and incremental AUC (iAUC) for 2‐h postprandial serum triglyceride (TG) levels and non‐esterified fatty acid (NEFA) levels were examined immediately after the 9‐h trial (post‐dinner) and the next morning (post‐breakfast). WALK8 reduced the post‐breakfast TG tAUC by 11% (P =.041) relative to SIT, and the effect was attenuated after adjustment for EE. The tAUC and iAUC indicated no significant treatment effects on post‐dinner TG and NEFA, and post‐breakfast NEFA in any of the activity‐break trials. EE was positively associated with the post‐breakfast NEFA iAUC (unstandardized β = 0.17 µmol/L/MJ [0.05‐0.28], P =.006). There was a chronic effect of interrupting sitting with short bouts (8 minutes) of brisk walking every 60 minutes on postprandial lipemia the following morning after intervention, and higher activity bout‐induced EE may be more effective in sedentary, healthy adults. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Purpose: This study aimed to determine whether interrupting prolonged sitting with three different walking-bout schedules improves glycemic metabolism relative to continuous prolonged sitting in sedentary adults. Methods: In a randomized, crossover trial, 16 inactive healthy adults (7 men, 24 ± 3 yr old) completed four 26-h laboratory sessions, including 22.5 h in an energy expenditure (EE)-testing calorimeter chamber. The four 9-h intervention periods were as follows: 9-h uninterrupted sitting (SIT), 30-min sitting/3-min brisk (60% V˙O2max) treadmill walk (WALK3), 45-min sitting/5-min (WALK5), or 60-min sitting/8-min (WALK8). Coprimary outcomes included the difference in the mean interstitial glucose concentration, total area under the curve (tAUC), and incremental area under the curve (iAUC) for the entire 26 and 9 h (intervention period) during three activity-bout conditions compared with SIT. Results: Compared with SIT, the 26-h mean glucose concentration was attenuated in WALK8 (Δmean −0.22 mmol·L−1 [95% confidence interval = −0.43 to −0.001], P = 0.048) without adjustment for EE and attenuated in WALK3 (Δ−0.47 mmol·L−1 [−0.75 to −0.10]), WALK5 (Δ−0.47 mmol·L−1 [−0.83 to −0.10]), and WALK8 (Δ−0.53 mmol·L−1 [−0.92 to −0.13]) after adjustment for EE (all P < 0.01). The 26-h tAUC was reduced in WALK3 (Δ−11.18 mmol·L−1 per 26 h [−20.07 to −2.29]), WALK5 (2.12.67 mmol·L−1 per 26 h [−22.54 to −2.79]), and WALK8 (Δ−13.85 mmol·L−1 per 26 h [−24.60 to −3.10]) (all P < 0.01), as well as the iAUC (all P < 0.05), only after adjustment for EE. The 9-h mean glucose concentration, tAUC, and iAUC decreased in the three activity-break conditions regardless of EE adjustment (all P < 0.05). Conclusions: All three walking-bout conditions improved glycemic metabolism compared with SIT, independent of EE, in inactive, healthy adults. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: 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.Methods: 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.Results: 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).Conclusions: 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. [ABSTRACT FROM AUTHOR]

Purpose:The purpose of this study was to develop and cross-validate an equation based on ActiGraph accelerometer GT3X output to predict children and youth's energy expenditure (EE) of physical activity (PA).Method:Participants were 367 Chinese children and youth (179 boys and 188 girls, aged 9 to 17 years old) who wore 1 ActiGraph GT3X accelerometer on their right hip during the following tests/activities: resting metabolic rate (RMR), six 5-min treadmill walk/runs (tested at different speeds: 3 km·h− 1, 4 km·h− 1, 5 km·h− 1, 6 km·h− 1, 7 km·h− 1, and 8 km·h− 1), 1 broadcast gymnastics, and 2 table-tennis exercises. Participants' oxygen consumption was measured using Cosmed K4b2. The participants were randomly divided into a calibration group (n = 331, 90%) and a cross-validation group (n = 36, 10%). The calibration group's data were used to determine the relationship between EE and triaxial vector magnitude counts (VM) using the Pearson correlation and to derive the equation using a stepwise multiple regression. In the cross-validation group, differences between measured and predicted EE were evaluated using pairwisettests.Results:VM activity counts had a moderately high correlation with EE (r = .758,p<  .01). An EE prediction equation was developed: EE (kcal·min− 1) = 0.00083 × VM+0.073 × weight − 2.01 (R2 = .72,SEE = 1.45 kcal·min− 1). According to the cross-validation study results, this equation could predict the EE within the range of known accuracy (i.e., about 20% error).Conclusions:An equation based on ActiGraph accelerometer VM activity counts was derived to predict EE of PA in Chinese children and youth within the range of known accuracy. [ABSTRACT FROM PUBLISHER]

Purpose:Many ActiGraph accelerometer cutoff points and equations have been developed to classify children and youth's physical activity (PA) into different intensity levels. Using a sample from the Chinese City Children and Youth Physical Activity Study, this study was to develop new ActiGraph cutoff points for moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) for Chinese children and youth and to compare the classification accuracy to that of a set of existing cutoff points.Method:A total of 367 Chinese children and youth (179 boys, 188 girls, ages 9–17 years old) had their resting metabolic rate measured and completed six 5-min treadmill walking/running tests (tested at different speeds: 3 km·h− 1, 4 km·h− 1, 5 km·h− 1, 6 km·h− 1, 7 km·h− 1, and 8 km·h− 1), one unit of the 3rd broadcast gymnastics (Version 3, Xi-Wang-Feng-Fan and Wu-Dong-Qing-Chun), and 2 sets of table tennis exercises (continuous attack and multiple balls). Participants wore 1 ActiGraph GT3X accelerometer on their right hip during each test, and their oxygen consumption and heart rate (HR) were measured using Cosmed K4b2and Polar HR transmitter. The participants were randomly divided into a calibration group (n = 331, 90%) and a cross-validation group (n = 36, 10%). Using the receiver-operating characteristic curve, the data from the calibration group were used to determine the cutoff points for MVPA and VPA. Using the data from the cross-validation group, classification accuracy of different cutoff points was evaluated through kappa statistics, sensitivity, and specificity.Results:A set of new cutoff points of counts per minute (CPM) was generated using the calibration data, and these cutoff points were proven to be more accurate compared with those developed in previous studies.Conclusion:When using ActiGraph accelerometers to measure the Chinese children and youth's PA, we recommended using the cutoff points of CPM ≥ 2,800 to define MVPA and CPM ≥ 4,000 for VPA. [ABSTRACT FROM PUBLISHER]

Background: The associations between various kinds of parental support and children and adolescents' physical activity (PA) are inconclusive. This study aimed 1) to examine the associations between various kinds of parental support and children and adolescents' moderate-to-vigorous physical activity (MVPA), and 2) to examine gender and age differences in the association between each specific kind of parental support and MVPA.Methods: Using a multi-stage stratified and random cluster sampling method, 711 schools in Shanghai were selected (data were collected from October 2014 to February 2015). In total, 61,429 school-aged children (6-18 years old, 50.7% boys) and their parents were included. Self-reported questionnaires were used to measure sociodemographic characteristics, MVPA and various kinds of parental support, including parental encouragement (PAEN), parental involvement (PAIV), parental financial support (PAFS) and, parental modeling (PAMD). Descriptive statistics and Chi-square were used to report the level of MVPA and its difference across various kinds of parental support by gender groups. The logistic regression analysis was used to examine the associations between parental support and MVPA with odds ratios (ORs) and 95% confidence intervals (CIs).Results: Overall, 19.4% of children and adolescents accumulated MVPA at least 60 min/day. Boys were more physically active than girls (21.4% > 17.4%, p <  0.001). According to the observation of OR estimates, girls may be more susceptible to the influences from various kinds of parental support than boys (OR = 1.59, 1.61, 1.27 and 1.63, 95% CI: 1.19-1.73 among girls, and OR = 1.48, 1.60, 1.21, and 1.60, 95% CI: 1.14-1.69 among boys for PAEN, PAIV, PAFS and PAMD respectively). PAMD is the only one supportive kind that was positively associated with MVPA in both genders across all grades (OR = 1.29-2.98, 95% CI: 1.09-4.08 among boys; OR = 1.27-2.64, 95% CI: 1.10-4.10 among girls).Conclusions: Less than one fifth of children and adolescents accumulated 60 min MVPA per day. Various kinds of parental support have important effects on children and adolescents' MVPA, which varied by gender and grades. PAMD, in particular, should be emphasized more than PAEN, PAIV and PAFS in family-based interventions aiming at increasing PA in the future. [ABSTRACT FROM AUTHOR]

The aim of the study is to investigate the relationship between physical activity as assessed by accelerometers and cognitive development across the human age ranges (from children and adolescents to adults). Additionally, this study seeks to explore whether physical activity contributes to cognitive development via modification of plasma insulin-like growth factor 1 (IGF-1) and brain-derived neurotrophic factor (BDNF). In the study, 500 preschool children (3.5–5.5 years old) are taking part in 6 triennial assessment waves over the span of 15 years. At each wave, participant measures included (a) 7-day physical activity monitoring using ActiGraph’s GT3X accelerometers, (b) the evaluation of cognitive development, (c) anthropometric and physical fitness assessments, (d) plasma IGF-1 and BDNF concentrations, and (e) retrospective questionnaires. Linear regression models are used to examine the effect of physical activity on cognitive development; plasma IGF-1 and BDNF concentrations are considered as mediators into data analyses. The results of the study may help to inform future health interventions that utilize physical activity as a means to improve cognitive development in children, adolescents, and adults. Additionally, the study may assist in determining whether the putative effects occur via modification of plasma IGF-1 or BDNF concentrations. [ABSTRACT FROM AUTHOR]

Background: There is limited evidence for the prevalence of the co-existence of physical activity (PA) and sedentary behavior (SED), and its correlates among children and adolescents. This study has two aims: 1) to investigate the prevalence of PA and SED, and their co-existence, and 2) to examine the associations between PA or SED, or both with gender and age among children and adolescents in Shanghai, China.Methods: Using a cross-sectional study design (conducted from September to December 2014), 50,090 children and adolescents (10-18 years old, 50.4% boys) were included in this study. A self-reporting questionnaire was used to measure participants' sociodemographic characteristics, PA, and SED. Descriptive statistics were used to describe sample characteristics, the prevalence of PA and SED, and their co-existence. A Generalized Linear Model was conducted to explore the associations between the prevalence of PA and SED, and their co-existence with gender and age separately.Results: Of the children and adolescents studied, only 18.4% met the guidelines for PA, 25.5% met the guidelines for SED, and 5.7% met the guidelines for both. Boys were more physically active (aOR = 1.43, 95% CI: 1.36-1.50), and girls were less sedentary (aOR = 1.29, 95%CI: 1.24-1.34). The prevalence of PA, SED, or both all declined as age increased (p < 0.001). Stratified analysis by gender revealed greater declining trends of meeting the PA or SED guidelines, or both in girls (all p < 0.005).Conclusion: Very few children and adolescents showed active lifestyles, and this was significantly related to age. Effective interventions aiming to promote PA and concurrently to limited SED among children and adolescents should be implemented as early as possible. [ABSTRACT FROM AUTHOR]

Purpose:The purpose of this study was to determine which method, individual information-centered (IIC) or group information-centered (GIC), is more efficient in recovering missing physical activity (PA) data.Method:A total of 2,758 Chinese children and youth aged 9 to 17 years old (1,438 boys and 1,320 girls) wore ActiGraph GT3X/GT3X+ accelerometers for 7 consecutive days. Those with no missing data (n = 900) were used to form a nonmissing sample, which, based on a semisimulation approach, was used to create a missing data set to evaluate a set of recovery methods, including 2 IIC and 22 GIC methods. Root mean square difference (RMSD), mean signed difference, and pairedttest were used to determine the effectiveness of the recovery methods.Results:The smallest RMSD values, which represent the most accurate recovery, were found with: (a) GIC-Expectation–maximization (GIC-EM) regardless of gender and by age (113,957.64); (b) GIC-EM regardless of gender and age (114,367.88); (c) GIC-EM regardless of age and by gender (114,697.06); (d) GIC-EM by gender and age (116,178.34); and (e) IIC averaging of remaining days (125,851.23).Conclusion:To recover 7-day PA accelerometer-determined activity missing data, we recommend using the GIC-EM and IIC approaches. [ABSTRACT FROM PUBLISHER]

Purpose:The purpose of this study was to investigate the characteristics of missing physical activity (PA) data of children and youth.Method:PA data from the Chinese City Children and Youth Physical Activity Study (N = 2,758; 1,438 boys and 1,320 girls; aged 9–17 years old) were used for the study. After the data were sorted by the weekday (WD) and recording day (RD), the missing ratio (MR) was calculated by gender, age, and body mass index (BMI). Chi-square tests were used to determine the effect of WD and RD on missing data. The joint impact (WD × RD) on the MR, as well as their interactions with age, gender, and BMI, were also analyzed.Results:Out of a total of 19,306 records, 5,400 (28.0%) were missing. The total MR significantly differed by WD and RD. There were more missing data during weekend days than during WDs, with the highest being on Sunday (36.2%). Older youth (aged 15–17 years old) had more missing data than did the 9- to 11-year-old group and 12- to 14-year-old group. In terms of RD, the 7th day had the most total missing data (36.0%), and again, older youth (15–17 years old) had more missing data than did the other 2 age groups. Gender and BMI had no impact on missing data by WD or RD. When the joint effect of WD and RD was examined, it was found that providing the measurement devices on Thursday and collecting data from Friday onward resulted in the lowest amount of missing data (18.5%).Conclusion:This study examined missing data characteristics with different sorting orders, which may help design more effective measures to prevent missing data in future PA measurement using accelerometers. [ABSTRACT FROM PUBLISHER]