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Purpose: This study aimed to determine whether estimated cardiorespiratory fitness (CRF), fat mass (FM), lean mass (LM), and adiponectin bidirectionally associate with arterial function and structure and if CRF mediates the relationship between cardiometabolic health and arterial outcomes in 9- to 11-yr-old children drawn from the Avon Longitudinal Study of Parents and Children birth cohort, United Kingdom. Methods : Brachial artery flow-mediated dilation (FMD), distensibility coefficient (DC), and carotid-radial pulse wave velocity (PWV) were measured by ultrasonography; CRF was measured during the submaximal ergometer test; total FM, trunk FM, and LM were measured by dual-energy x-ray absorptiometry; plasma adiponectin was measured by enzyme assay; and cardiometabolic health was computed based on the International Diabetes Federation criteria for diagnosing metabolic syndrome. We tested bidirectionality by including CRF, FM, LM, and adiponectin as exposures and FMD, DC, and PWV as outcomes, alternatively. Results : Among 5566 participants (2816 (51%) girls; median age, 9.75 yr), CRF per body mass0.21 was directly related to DC ([beta] (95% confidence interval) = 0.004 (<0.0001 to 0.008); P = 0.046), whereas CRF per LM0.54 was inversely associated with PWV (- 0.034 (-0.063 to -0.003); 0.032) after adjusting for covariates. These associations remained in bidirectional analyses. Total FM, trunk FM, and LM were bidirectionally and positively associated with FMD and DC. Total FM and trunk FM but not LM had bidirectional and inverse associations with PWV. Adiponectin was not related to FMD, DC, or PWV. CRF partially mediated the associations of cardiometabolic health with FMD (1.5% mediation), DC (12.1% mediation), and PWV (3.5% mediation). Conclusions : Associations of poor cardiometabolic health with adverse arterial structure and function in childhood may be mitigated by increasing CRF. Higher CRF was associated with better arterial structure whereas higher total FM and trunk FM were associated with better arterial function and structure. In the reverse analysis, healthy arterial structure and function were independently associated with increased total FM and trunk FM, suggesting an "arterial paradox." [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to describe associations between physical and social environmental features of preschools and physical activity behaviors of young children with developmental disabilities. Methods: A sample of 34 preschool-age children (mean age, 4.28 ± 1.07; male, 64.7%) with developmental disabilities participated in this study. Physical activity and preschool environmental factors were measured through direct observation using the Observational System for Recording Physical Activity in Children—Developmental Disabilities version. Children were observed approximately eight times over the course of a week, yielding a total of 11, 310 observation intervals. The number of intervals and percentage of time spent in physical activity across environmental contexts were calculated. Logistic regression analyses were conducted to determine associations between time spent in physical activity and features of the physical and social environment. Results: Children with disabilities were sedentary for most of the observed intervals (81.5%). Children were 4.8 times (confidence interval (CI), 4.25–5.50) more likely to be physically active while outdoors compared with indoors. Physical activity was more likely to occur in open spaces (odds ratio [OR], 3.3; CI, 2.59–4.19) and when using portable play equipment (OR, 2.7; CI, 1.31–5.64) compared with fixed playground equipment. While indoors, children in this study were 5.6 times (CI, 3.78–8.03) more likely to be active when in therapy compared with group time activities. Physical activity was more likely to occur when in solitary (OR, 3.4; CI, 2.87–4.10) or one-on-one group contexts (OR, 1.7–2.9) compared with in groups with an adult present. Conclusions: Certain features of the preschool setting, such as location and social group composition, were more conducive to physical activity than others. Children with disabilities would benefit from more time outdoors and in smaller group settings during preschool. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to quantify age-related changes in accelerometer-derived day-level physical activity and sedentary behavior pattern metrics (i.e., number, length, and temporal dispersion of bouts and breaks) across 3 yr of middle childhood. Differences by child sex and weekend versus weekday were examined. Method: Children (N = 169, 54% female, 56% Hispanic; 8-12 yr old at enrollment) participated in a longitudinal study with six assessments across 3 yr. Day-level moderate-to-vigorous physical activity (MVPA; i.e., total minutes, number of short (<10 min) bouts, proportion of long (≥20 min) bouts, temporal dispersion) and sedentary behavior (i.e., total minutes, number of breaks, proportion of long (≥60 min) bouts, temporal dispersion) pattern metrics were measured using a waist-worn accelerometer (Actigraph GT3X). Results: Random intercept multilevel linear regression models showed that age-related decreases in the number of short MVPA bouts per were steeper for girls than for boys (b = -1.28; 95% confidence interval (CI), -1.93 to -0.64; P < 0.01) and on weekend days than on weekdays (b = -1.82; 95% CI, -2.36 to -1.29; P < 0.01). The evenness of the temporal dispersion of MVPA across the day increased more on weekend days than on weekdays as children got older (b = -0.02; 95% CI, -0.02 to -0.01; P < 0.01). Girls had steeper age-related decreases in the number of sedentary breaks per day (b = -2.89; 95% CI, -3.97 to -1.73; P < 0.01) and the evenness of the temporal dispersion of sedentary behavior across the day (b ≤ 0.01; 95% CI, <0.01 to 0.01; P < 0.01) than did boys. Changes in sedentary behavior metrics did not differ between weekend days and weekdays. Conclusion: Strategies to protect against declines in short physical activity bouts and promote sedentary breaks, especially among girls and on weekend days, could reduce cardiometabolic risks. [ABSTRACT FROM AUTHOR]

Purpose: Few studies have investigated the independent and joint associations of cardiorespiratory fitness (CRF) and body fat percentage (BF%) with insulin resistance in children. We investigated the independent and combined associations of CRF and BF% with fasting glycemia and insulin resistance and their interactions with physical activity (PA) and sedentary time among 452 children age 6 to 8 yr. Methods: We assessed CRF with a maximal cycle ergometer exercise test and used allometrically scaled maximal power output (W max) for lean body mass (LM1.13) and body mass (BM1) as measures of CRF. The BF% and LM were measured by dual-energy X-ray absorptiometry, fasting glycemia by fasting plasma glucose, and insulin resistance by fasting serum insulin and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The PA energy expenditure, moderate-to-vigorous PA (MVPA), and sedentary time were assessed by combined movement and heart rate sensor. Results: W max/LM1.13 was not associated with glucose (β = 0.065, 95% confidence interval [CI] = −0.031 to 0.161), insulin (β = −0.079, 95% CI = −0.172 to 0.015), or HOMA-IR (β = −0.065, 95% CI = −0.161 to 0.030). W max/BM1 was inversely associated with insulin (β = −0.289, 95% CI = −0.377 to −0.200) and HOMA-IR (β = −0.269, 95% CI = −0.359 to −0.180). The BF% was directly associated with insulin (β = 0.409, 95% CI = 0.325 to 0.494) and HOMA-IR (β = 0.390, 95% CI = 0.304 to 0.475). Higher W max/BM1, but not W max/LM1.13, was associated with lower insulin and HOMA-IR in children with higher BF%. Children with higher BF% and who had lower levels of MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR. Conclusions: Children with higher BF% together with less MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR. Cardiorespiratory fitness appropriately controlled for body size and composition using LM was not related to insulin resistance among children. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the longitudinal associations of cardiorespiratory fitness (CRF), motor competence (MC), and body fat percentage (BF%) with cognition in children. Methods: Altogether, 371 children (188 boys and 183 girls) 6–9 yr of age at baseline participated in this 2-yr follow-up study. We assessed CRF by maximal cycle ergometer test, computed the MC score from the z -scores of the 50-m shuttle run, static balance, and box and block test results, measured BF% by dual-energy x-ray absorptiometry, and assessed cognition using the Raven's Coloured Progressive Matrices (RCPM) score. The associations were studied by linear regression analysis and repeated-measures ANCOVA. Results: In boys, a higher MC score (β = −0.161, 95% confidence interval [CI] = −0.314 to −0.009), a shorter 50-m shuttle run test duration (β = 0.152, 95% CI = 0.007–0.296), and a higher number of cubes moved in the Box and block test (β = −0.161, 95% CI = −0.309 to −0.013) at baseline were associated with a smaller increase in the RCPM score during follow-up. These associations were largely explained by the RCPM score at baseline. However, boys in the highest third (mean difference = 2.5, 95% CI for difference = 0.66–4.33) and the middle third (mean difference = 2.1, 95% CI for difference = 0.39–3.82) of the MC score at baseline had a higher RCPM score over the 2-yr follow-up than boys in the lowest third. CRF, MC, or adiposity was not associated with the RCPM score in girls. Changes in CRF, MC, or BF% were not associated with changes in cognition. Conclusions: Higher MC at baseline predicted better cognition during the first two school years in boys but not in girls. CRF or adiposity was not associated with cognition in boys or girls. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Purpose: The first aim was to develop a dynamic measure of physical competence that requires a participant to demonstrate fundamental, combined and complex movement skills, and assessors to score both processes and products (Dragon Challenge [DC]). The second aim was to assess the psychometric properties of the DC in 10- to 14-yr-old children. Methods: The first phase involved the development of the DC, including the review process that established face and content validity. The second phase used DC surveillance data (n = 4355; 10–12 yr) to investigate construct validity. In the final phase, a convenience sample (n = 50; 10–14 yr) performed the DC twice (1-wk interval), the Test of Gross Motor Development-2 (TGMD-2), and the Stability Skills Assessment (SSA). These data were used to investigate concurrent validity, and test–retest, interrater and intrarater reliabilities. Results: In support of construct validity, boys (P < 0.001) and secondary school children (P < 0.001) obtained higher DC total scores than girls and primary school children, respectively. A principal component analysis revealed a nine-component solution, with the three criteria scores for each individual DC task loading onto their own distinct component. This nine-factor structure was confirmed using a confirmatory factor analysis. Results for concurrent validity showed that there was a high positive correlation between DC total score and TGMD-2 and SSA overall score (r (43) = 0.86, P < 0.001). DC total score showed good test–retest reliability (intraclass correlation coefficient = 0.80; 95% confidence interval, 0.63, 0.90; P < 0.001). Interrater and intrarater reliabilities on all comparison levels was good (all intraclass correlation coefficients > 0.85). Conclusion: The DC is a valid and reliable tool to measure elements of physical competence in children age 10 to 14 yr. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate methods for infants' physical activity measurement based on accelerometry, including the minimum number of measurement days and placement of a wrist or ankle device. We also evaluated the acceptability of the device among infants and mothers. Methods: A cross-sectional mixed-methods study was conducted on a convenience sample of 90 infants. Physical activity was measured using the Actigraph GT3X+ accelerometer placed on the wrist and/or ankle for 7 consecutive days (worn for 24 h), and a qualitative interview was performed to verify acceptability. The intraclass correlation coefficient (ICC) method and the Bland and Altman's dispersion diagram were used to verify the minimum number of measurement days. All analyses were stratified by walking status. Results: The mean (SD) age was 12.9 (1.70) months; the mean acceleration varied between 25.8 mg (95% confidence interval (CI), 14.3-52.7) and 27.3 mg (95% CI, 17.9-44.5) using the wrist placement, and between 24.9 mg (95% CI, 10.6-48.4) and 26.2 mg (95% CI, 11.7-65.6) using the ankle placement. The ICC results showed a lower acceleration variability between days among infants incapable of walking; they achieved an ICC of 0.80 with 1 d of measurement in both placements. Among those capable of walking, the minimum number of days to achieve an ICC of 0.80 was 2 d measured at the wrist (0.85; 95% CI, 0.71-0.93) and 3 d measured at the ankle (0.92; 95% CI, 0.84-0.96). The qualitative results pointed to the wrist placement as the preferred placement among the overall sample. Conclusions: Two and three measurement days with the accelerometer placed on the wrist and ankle, respectively, seemed to adequately represent a week of measurement. The accelerometer placed on the wrist had better acceptance by the infants and mothers. [ABSTRACT FROM AUTHOR]

Introduction: Physical Literacy Assessment for Youth (PLAYfun) is a measure of motor competence, comprehension, and confidence which is part of a suite of scales used to assess physical literacy in children and youth; however, its measurement properties have not been reported in the published literature. The purpose of this study is to examine the factor structure of PLAYfun, in addition to variations in PLAYfun subscale results by age and sex. Method: In this study, we use a sample of children and youth 7 to 14 yr of age (n = 215) to test a proposed factor structure for the motor competence component of PLAYfun and to examine age and sex differences in subscale and total scores. The initial (n = 128) and secondary (n = 98) samples were drawn from a stratified (by geographic region), random sample of 27 after-school programs from a larger pool of 400 programs across the province of Ontario. Seven research assistants were initially trained on the administration of PLAYfun and rated a small pilot sample of 10 children. These trained assessors then assessed the full sample. Results: Interrater agreement was very good (intraclass correlation, 0.87). The hypothesized five-factor structure of the scale was found to have an acceptable fit to the data (root mean square error of approximation, 0.055; 90% confidence interval, 0.03-0.075; comparative fit index, 0.95; Tucker-Lewis Index, 0.94). In general, PLAYfun scores increased with age as developmentally expected. There were few sex differences across skills, but girls did not perform as well as boys on upper and lower body object control skills. Conclusions: The factor structure and patterns of results by age and sex support PLAYfun as a measure of motor competence. Continued evaluation of the tool and other subscales of PLAY is required. [ABSTRACT FROM AUTHOR]

Purpose: Pattern recognition approaches to accelerometer data processing have emerged as viable alternatives to cut-point methods. However, few studies have explored the validity of pattern recognition approaches in preschoolers, and none have compared supervised learning algorithms trained on hip and wrist data. Purpose of this study was to develop, test, and compare activity class recognition algorithms trained on hip, wrist, and combined hip and wrist accelerometer data in preschoolers. Methods: Eleven children 3-6 yr of age (mean age, 4.8 ± 0.9 yr) completed 12 developmentally appropriate physical activity (PA) trials while wearing an ActiGraph GT3X+ accelerometer on the right hip and nondominant wrist. PA trials were categorized as sedentary, light activity games, moderate-to-vigorous games, walking, and running. Random forest (RF) and support vector machine (SVM) classifiers were trained using time and frequency domain features from the vector magnitude of the raw signal. Features were extracted from 15-s nonoverlapping windows. Classifier performance was evaluated using leave-one-out cross-validation. Results: Cross-validation accuracy for the hip, wrist, and combined hip and wrist RF models was 0.80 (95% confidence interval (CI), 0.79-0.82), 0.78 (95% CI, 0.77-0.80), and 0.82 (95% CI, 0.80-0.83), respectively. Accuracy for hip, wrist, and combined hip and wrist SVM models was 0.81 (95% CI, 0.80-0.83), 0.80 (95% CI, 0.79-0.80), and 0.85 (95% CI, 0.84-0.86), respectively. Recognition accuracy was consistently excellent for sedentary (990%); moderate for light activity games, moderate-to-vigorous games, and running (69%-79%); and modest for walking (61%-71%). Conclusions: Machine learning algorithms such as RF and SVM are useful for predicting PA class from accelerometer data collected in preschool children. Although classifiers trained on hip or wrist data provided acceptable recognition accuracy, the combination of hip and wrist accelerometer delivered better performance. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the validity of wrist acceleration cut points for classifying moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) physical activity. Methods: Fifty-seven children (5-12 yr) completed 15 semistructured activities. Three sets of wrist cut points (9192 mg, 9250 mg, and 9314 mg), previously developed using Euclidian norm minus one (ENMO192+), GENEActiv software (GENEA250+), and band-pass filter followed by Euclidian norm (BFEN314+), were evaluated against indirect calorimetry. Analyses included classification accuracy, equivalence testing, and Bland-Altman procedures. Results: All cut points classified MPA, VPA, and MVPA with substantial accuracy (ENMO192+: J = 0.72 [95% confidence interval = 0.72-0.73], MVPA: area under the receiver operating characteristic curve (ROC-AUC) = 0.85 [0.85-0.86]; GENEA250+: J = 0.75 [0.74-0.76], MVPA: ROC-AUC = 0.85 [0.85-0.86]; BFEN314+: J = 0.73 [0.72-0.74], MVPA: ROC-AUC = 0.86 [0.86-0.87]). BFEN314+ misclassified 19.7% non-MVPA epochs as MPA, whereas ENMO192+ and GENEA250+ misclassified 32.6% and 26.5% of MPA epochs as non-MVPA, respectively. Group estimates of MPA time were equivalent (P < 0.01) to indirect calorimetry for the BFEN314+ MPA cut point (mean bias =-1.5%, limits of agreement [LoA] = -57.5% to 60.6%), whereas estimates of MVPA time were equivalent (P < 0.01) to indirect calorimetry for the ENMO192+ (mean bias = -1.1%, LoA = -53.7% to 55.9%) and GENEA250+ (mean bias = 2.2%, LoA = -56.5% to 52.2%) cut points. Individual variability (LoA) was large for MPA (min: BFEN314+, -60.6% to 57.5%; max: GENEA250+, -42.0% to 104.1%), VPA (min: BFEN314+, -238.9% to 54.6%; max: ENMO192+, -244.5% to 127.4%), and MVPA (min: ENMO192+, -53.7% to 55.0%; max: BFEN314+, -83.9% to 25.3%). Conclusion: Wrist acceleration cut points misclassified a considerable proportion of non-MVPA and MVPA. Group-level estimates of MVPA were acceptable; however, error for individual-level prediction was larger. [ABSTRACT FROM AUTHOR]

Introduction: The randomized controlled trial ''Physical Activity in Pediatric Cancer'' determined the effects of an inhospital exercise intervention combining aerobic and muscle strength training on pediatric cancer patients with solid tumors undergoing neoadjuvant chemotherapy. Methods: Participants were allocated to an exercise (n = 24, 17 boys; mean ± SEM age, 10 ± 1 yr) or control group (n = 25, 18 boys; 11 ± 1 yr). Training included three sessions per week for 19 ± 2 wk. Participants were assessed at treatment initiation, termination, and 2 months after end treatment. The primary endpoint was muscle strength (as assessed by upper and lower-body five-repetition-maximum tests). Secondary endpoints included cardiorespiratory fitness, functional capacity during daily life activities, physical activity, body mass and body mass index, and quality of life. Results: Most sessions were performed in the hospital's gymnasium. Adherence to the program averaged 68% ± 4% and no major adverse events or health issues were noted. A significant interaction (group-time) effect was found for all five-repetition maximum tests (leg/bench press and lateral row; all P < 0.001). Performance significantly increased after training (leg press: 40% [95% confidence interval [CI], 15-41 kg); bench press: 24% [95% CI, 6-14 kg]; lateral row 25% [95% CI, 6-15 kg]), whereas an opposite trend was found in controls. Two-month post values tended to be higher than baseline for leg (P = 0.017) and bench press (P = 0.014). In contrast, no significant interaction effect was found for any of the secondary endpoints. Conclusion: An inhospital exercise program for pediatric cancer patients with solid tumors undergoing neoadjuvant treatment increases muscle strength despite the aggressiveness of such therapy. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the prospective associations of reallocating time spent in different types of sedentary behavior, physical activity, and sleep with body mass index (BMI) in children using isotemporal substitution analysis. Methods: Chinese children in grades 1-3 were recruited to a cohort study in 2009 and were followed up over a 2-yr period. Reports were gathered from the parents on children's sedentary behavior, sleep duration, and sociodemographic variables. The reported sedentary behavior types were then grouped into three categories: screen time (e.g., watching TV), academic-related activities (e.g., doing homework), and other sedentary behaviors (e.g., sitting and talking). Moderate-to-vigorous physical activity (MVPA) and light-intensity physical activity were assessed by ActiGraph accelerometry (ActiGraph, Pensacola, FL). Isotemporal substitution models were performed to examine the effects of time allocation on BMI. Results: A total of 672 children (359 boys, mean age at recruitment = 7.6 yr) who had provided valid accelerometer data for at least one assessment time point were included in the analysis. Controlling for covariates and total behavior time, isotemporal substitution models indicated that the displacement of 30 min⋅d-1 of other sedentary behaviors with equal amounts of screen time (B = 0.12; 95% confidence interval, 0.04-0.20) or academic-related activities (B = 0.13; 95% confidence interval, 0.04-0.21) was associated with higher BMI. Reallocating 30 min⋅d-1 of MVPA with each of the sedentary behavior variables resulted in increased BMI. Conclusions: The substitution of screen time or academic-related activities with other sedentary behaviors or MVPA was associated with lower BMI in Chinese children. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to identify unique organized sport trajectories from early childhood to late adolescence in an Australian pregnancy cohort, the Raine Study. Methods: Participation in organized sport was assessed at ages 5, 8, 10,14, and 17 yr. Physical activity, body composition, and self-rated physical and mental health were assessed at the age of 20 yr. Latent class analysis was used to identify patterns of sport participation. To assess the internal validity of the trajectory classes, differences in health characteristics between trajectories were analyzed using generalized linear models. Results: For girls, three trajectory classes were identified: consistent sport participators (47.5%), sport dropouts (34.3%), and sport nonparticipators (18.1%). For boys, three trajectory classes were identified: consistent sport participators (55.2%), sport dropouts (36.9%), and sport joiners (8.1%). For girls, there were overall differences across trajectory classes in lean body mass (P = 0.003), lean mass index (P = 0.06), and physical health (P = 0.004). For boys, there were differences across classes in physical activity (P = 0.018), percent body fat (P = 0.002), lean body mass (P < 0.001), lean mass index (P < 0.001), physical health (P = 0.06), and depression scores (P = 0.27). Conclusion: This study identified unique, sex-specific trajectories of organized sport participation. The differences in health outcomes between trajectory classes, such as participants with consistent sport participation having more preferable health outcomes at the age of 20 yr, support the internal validity of the trajectories. Strategies are needed to identify and encourage those in the dropout trajectory to maintain their participation and those in the nonparticipator or joiner trajectories to join sport earlier. Specifically, interventions to encourage early sport participation in girls and help nonparticipating boys to join sport during adolescence may help more children receive the benefits of sport participation. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to examine the prospective associations between cardiorespiratory fitness (CRF) and academic achievement in the youth. Methods: The sample included 1286 fifth-, sixth-, and seventh-grade students, age 11 to 14 yr (Mage = 11.3 T 1.1), from 14 schools followed for 3 yr. Academic achievement was assessed using the students' marks at baseline and at follow-up 3 yr apart, in Portuguese, mathematics, foreign language (English), and science. CRF was assessed by the Progressive Aerobic Cardiovascular Endurance Run test from the Fitnessgram battery. Students were classified as fit-fit, unfit-fit, fit-unfit, and unfit-unfit according to the Progressive Aerobic Cardiovascular Endurance Run test results at baseline and follow-up. Ordinal regression analyses were performed to examine associations between CRF and academic achievement. Results: Being persistently fit (fit-fit), compared with those classified unfit-unfit, increased the odds of having high levels of academic achievement in Portuguese (odds ratio (OR) = 3.49; 95% CI, 1.97-6.20; P < 0.001) and foreign language (OR = 2.41; 95% CI, 1.39-4.14; P < 0.01) at follow-up. Students that improved their CRF and became fit (unfit-fit) had also higher odds of achieving better marks than those persistently unfit-unfit in Portuguese (OR = 2.52; 95% CI, 1.42-4.45; P < 0.01) and foreign language (OR = 2.13; 95% CI, 1.23-3.67; P < 0.01). Conclusion: Consistently high and improvements in cardiorespiratory fitness are prospectively associated with better academic achievement especially in mother tongue and foreign language. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to determine whether blood lipids in healthy preadolescent children are sensitive to normally occurring changes in percent body fat, physical activity (PA), cardiorespiratory fitness (CRF), and macronutrient intake. Methods: Repeated measurements of fasting serum LDL cholesterol, HDL cholesterol, and triglycerides (TG); percent body fat (dual-energy x-ray absorptiometry); PA (pedometers); CRF (multistage run); and carbohydrate, sugar, and fat intake (dietary recall and record) were carried out in 469 children (51% girls) age 8, 10, and 12 yr. Results: Longitudinal relationships in boys showed that, for every one-unit increase in percent body fat, there was a 1.3% (95% CI, 0.9-1.8; P < 0.001) increase in LDL cholesterol; among girls, the increase was 0.8% (95% CI, 0.3-1.2; P = 0.003). In addition, we found a positive longitudinal relationship between TG and percent body fat (P < 0.001) in girls, and a negative longitudinal relationship between HDL cholesterol and percent body fat (P = 0.03) in boys. There were also longitudinal relationships between TG and CRF in both sexes (P < 0.05), but these were not sustained upon adjustment for percent body fat. Although cross-sectional relationships occurred in girls for both HDL cholesterol and TG with PA (P < 0.05), we found no evidence of any relationships between lipids and fat or sugar intake. By age 12 yr, LDL cholesterol was elevated (>3.36 mmol ⋅L-1) in 16% and 20% of girls and boys, respectively. Conclusions: Blood lipids in preadolescent children appear sensitive to normal changes occurring in their percent body fat and, thus, fitness. Our data support early attention to body composition in community strategies designed to prevent cardiovascular disease in later life. [ABSTRACT FROM AUTHOR]

Purpose: Physical activity (PA) declines dramatically during adolescence, and activity levels are consistently lower among children living in low-income communities. Competency in a range of fundamental movement skills (FMS) may serve as a protective factor against the decline in PA typically observed during adolescence. The purpose of this study was to evaluate the effect of a 12-month multicomponent PA and FMS intervention on children attending primary schools in low-income communities. Methods: The Supporting Children's Outcomes using Rewards, Exercise, and Skills intervention was evaluated using a cluster randomized controlled trial. The sample included 25 classes from eight primary schools located in low-income communities. Participants were 460 children (54.1% girls) age 8.5 ± 0.6 yr. Primary outcomes were objectively measured PA (ActiGraph GT3X and GT3X+ accelerometers), FMS competency (Test of Gross Motor Development 2, six locomotor and six object control skills), and cardiorespiratory fitness (20-m multistage fitness test) assessed at baseline, midprogram (6-months), and at posttest (12 months). Linear mixed models, adjusted for sex, age, body mass index z-score, socioeconomic status, ethnicity, and school class as a random factor, were used to assess the effect of the intervention. Results: At midprogram, there were no significant intervention effects for any of the outcomes. At posttest (study's primary time point), there were intervention effects for daily moderate-to-vigorous PA (MVPA) (adjusted mean difference, 12.7 min·d-1 of MVPA; 95% confidence interval (CI), 5.0-20.5), overall FMS competency (4.9 units; 95% CI, j0.04 to 9.8), and cardiorespiratory fitness (5.4 laps; 95% CI, 2.3-8.6). Conclusions: A school-based multicomponent PA and FMS intervention maintained daily MVPA, improved overall FMS competency, and increased cardiorespiratory fitness among children attending primary schools in low-income communities. [ABSTRACT FROM AUTHOR]

Purpose: (1) Examine the influence of extra physical education (EPE) on the number of musculoskeletal injuries in public schools accounting for organized sports participation (OSP) outside school. (2) Examine the major injury subgroup: growth-related overuse (GRO) through the overuse-related injury group. Methods: A longitudinal controlled school-based study among Danish public schools. At baseline, 1216 children participated age 6.2-12.4 yr. Six schools (701 children) with EPE and four control schools (515 children) were followed up with weekly automated mobile phone text messages for information on musculoskeletal problems and OSP. Health care personnel diagnosed the children according to the World Health Organization's International Classification of Diseases, Tenth Revision. Data were analyzed using a two-part zero-inflated negative binomial (ZINB) regression model. Results: School type had no influence on the odds of sustaining an injury but increased the probability of sustaining a higher injury count for children with injuries, with total injuries by a factor of 1.29 (95% confidence interval [CI] = 1.07-1.56), overuse by a factor of 1.29 (95% CI = 1.06-1.55), and GRO by a factor of 1.38 (95% CI = 1.02-1.80). Weekly mean OSP decreased the odds of belonging to the group of children with no injuries, by a factor of 0.29 (95% CI = 0.14-0.58), 0.26 (95% CI = 0.14-0.48), and 0.17 (95% CI = 0.06-0,52) for total, overuse, and GRO, respectively. OSP also increased the probability of sustaining a higher injury count for children with injuries by a factor of 1.11 (95% CI = 1.02-1.22), 1.10 (95% CI = 1.00-1.22), and 1.14 (95% CI = 1.00-1.30), respectively. Conclusions: Children enrolled in EPE schools with high OSP have the highest odds of injury and a high probability of sustaining a higher injury count compared to their peers at schools with normal PE. Special attention should be assigned to these children during compulsory PE. [ABSTRACT FROM AUTHOR]

Experts recommend children spend more time playing outdoors. The ambient light sensor of the ActiGraph GT3X+ provides lux measurements. A lux is the International System's unit of illumination, equivalent to one lumen per square meter. Few studies have established a lux threshold for determining whether a child is indoors or outdoors. Purpose: The purpose of the study was: (1) to assess the reliability of the ActiGraph GT3X+ ambient light sensor, (2) to identify a lux threshold to accurately discriminate between indoor and outdoor activities in children, and (3) to test the accuracy of the lux threshold in a free-living environment. Methods: In part one, a series of reliability tests were performed using 20 ActiGraph GT3X+ monitors under different environmental conditions. Cronbach's alpha was used to determine inter-instrument reliability. In part two, 18 children performed 11 different activities (five indoors and six outdoors) for six minutes each. The optimal threshold for detecting indoor/outdoor activity was determined using ROC curve analysis. In part three, 18 children at a preschool wore the monitor during a school day. Percent accuracy was determined for all conditions. Results: Part one: The devices had Cronbach's alpha values of 0.992 and 1.000 for indoor and outdoor conditions, respectively, indicating high inter-instrument reliability. Part two: The optimal lux threshold was determined to be 240 lux [sensitivity=0.92, specificity=0.88, AUC=0.96 (95% CI, 0.951-0.970)]. Part three: Results of the school-day validation demonstrated the monitor was 97.0% accurate for overall detection of indoor and outdoor conditions (outdoor=88.9%, indoor=99.1%). Conclusions: The results demonstrate that an ActiGraph GT3X+ lux threshold of 240 can accurately assess indoor and outdoor conditions of preschool children in a free-living environment. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the tracking of physical activity (PA) during a 10-yr period and to investigate whether sex differences in PA trajectories are altered after aligning by maturity instead of age. Methods: The Iowa Bone Development Study collected accelerometer data on a cohort of 140 girls and 128 boys at ages 5, 9, 11, 13, and 15 yr. Logistic regression determined the odds ratio of being in lowest PA tertile at 15 yr if in lowest tertile at age 5 yr. Spearman correlation coefficients examined PA tracking from age 5 to 15 yr. Using additional Iowa Bone Development participants at ages 9, 11, 13, and 15 yr (N = 482, 457, 416, and 316, respectively), we examined the stability of PA for chronological and biological age in 2-yr intervals surrounding peak height velocity (PHV) age. Year from PHV was estimated using the Mirwald prediction equation. Results: Girls had significant 10-yr correlations (r = 0.27); boys did not. Girls, not boys, were more likely to be in the lowest tertile for PA at age 15 yr if in the lowest tertile at age 5 yr (moderate to vigorous PA: odds ratio = 3.1,95% confidence interval = 1.4-6.9; vigorous PA: odds ratio = 2.8, 95% confidence interval = 1.2-6.1). Girls' 2-yr intervals for PA showed moderate associations (r = 0.31-0.56) when aligned chronologically but were moderate to high (r = 0.41-0.63) when aligned biologically. Boys' associations were low to moderate {r = 0.26-0.56) chronologically. When aligned biologically, the associations were low for the -1- to 1-yr interval (1 yr before the 1-yr post-PHV) but moderate to high for the -2- to 0-yr and 0- to 2-yr intervals (r = 0.50-0.61). Conclusions: Physical activity tracking from childhood to adolescence is stronger in girls than that in boys. Intervention programs targeting boys should focus on time surrounding puberty in boys during which activity patterns change. [ABSTRACT FROM AUTHOR]

Introduction: Acute moderate-intensity exercise reduces postprandial lipemia in boys. However, the effect of high-intensity exercise has not been investigated. This study examined the effect of low- volume, high-intensity interval running (HIIR) on postprandial plasma triacylglycerol (TAG) concentrations. Methods: Fifteen healthy, active boys (means ± SD; age = 11.8 + 0.4 yr, body mass = 42.8 ± 8.0 kg, peak oxygen uptake [VO2] = 55 + 6 mL•kg−1•min−1) completed two 2-d trials in a counterbalanced, crossover design separated by 14 d. On day 1, participants rested (CON) or completed 10x1 min running intervals at 100% maximal aerobic speed, determined from an incremental peak VO2 test, with 1 min recovery between intervals (HIIR). On day 2, capillary blood samples were taken in the fasted state and at predetermined intervals throughout the 6.5-h postprandial period while participants rested. A standardized breakfast was consumed at 0800 h, immediately after the fasting sample, and a standardized lunch meal was consumed at 1200 h. Results: Differences in fasting plasma TAG concentration were small to moderate (95% confidence interval [CI] = -0.11 to 0.01, effect size [ES] = 0.40). Postprandial TAG concentration was lower during HIIR compared with CON (95% CI = -0.19 to -0.02, ES = 0.58). The total area under the TAG concentration versus time curve was lower after HIIR compared with CON (5.2 ± 1.1 vs 5.8 ± 1.5 mmol•L−1 6.5 h; 95% CI = -1.18 to -0.12, ES = 0.50). Conclusion: This is the first study to show that low-volume HIIR attenuates postprandial TAG concentration in healthy, active 11- to 12-yr-old boys. [ABSTRACT FROM AUTHOR]

Purpose: The Centers for Disease Control and Prevention indicates that depression is a serious issue for teenagers, with 10% to 15% reporting some symptoms and 15% having considered attempting suicide in 2009. Purpose: The objective of this study is to determine the relations between cardiorespiratory fitness and body mass index (BMI) and depressive symptoms among young adolescents. Methods: The sample included 531 females and 455 males in grades 6 to 8. The FITNESSGRAM® physical fitness test battery was administered to the participants as part of required school activities. Two results from the test battery, cardiorespiratory fitness and BMI, were used to classify the students into meeting or not meeting the healthy fitness zones established for each test. The Center for Epidemiological Studies-Depression Scale for Children (CES-DC) was administered in the schools to assess behavioral and cognitive aspects of depression. Participants were classified as elevated depression (CES-DC ≥16, n = 295) or normal (<16, « = 691). Results: Logistic regression was used to assess the relations of Health Fitness Zone status for cardiorespiratory fitness and BMI with depression while controlling for age, ethnicity, sex, economic status (school lunch support), and other fitness factors (cardiorespiratory fitness or BMI). Children classified as not in the Health Fitness Zone for cardiorespiratory fitness had significantly higher odds of elevated depression (odds ratio = 1.71 (95% CI = 1.03-2.84)). BMI was not significantly related to depression. Conclusion: These findings indicate that a healthy level of cardiorespiratory fitness was associated with a lower level of depression as measured by the CES-DC. Because of the cross-sectional nature of this study, no cause and effect relations can be assumed. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to provide sex and age-specific normative values on pedometer-determined steps per day for children and adolescents so that researchers, clinicians/practitioners, other childcare workers, and families can compare children's and adolescents' pedometer-determined data to that of their peers. Researchers evaluated data from between 2005 and 2011 on 21,271 children between the ages of 5-12 and 12,956 adolescents between the ages of 13-19. They found that mean steps per day increased from 11,602 steps per day among five year olds to a sample peak mean value of 12,348 steps per day among 10 year olds, and then declined to 9778-10,073 among 15 to 19 year olds and that mean steps per day were higher among boys than girls at every age.

The article focuses on research which was conducted to examine changes in physical activity among children and adolescents by race/ethnicity in the United States from 2003-2004 to 2005-2006. Researchers evaluated data from more than 3,000 children. They found that physical activity decreased with age, boys were more active than girls, and non-Hispanic black children were more active than non-Hispanic whites. They concluded that because a lack of improvement in physical activity and an emerging race-ethnic disparity were found, more research was needed on physical activity among U.S. children.

The article reports on research which was conducted to investigate whether recreational cycling is associated with cardiorespiratory fitness (CRF). Researchers evaluated 5,578 British school children between the ages of 10 and 16 who were recreational cyclists of one degree or another. They found that recreational cycling may provide an alternative target for interventions to increase physical activity and improve CRF in youth. They concluded that recreational cycling could potentially serve as a way to gain cycling confidence and establish habits that act as precursors to commuter cycling.

The article presents a randomized controlled trial to evaluate the Hunter Illawarra Kids Challenge Using Parent Support physical activity program for overweight children in New South Wales. The evaluation involve three intervention programs, the child-centered physical activity skill development program, parent-centered dietary modification program, and both programs combined. It examined movement skill proficiency, perceived athletic competence, accelerometer-assessed physical activity, and parent-reported time spent in screen behaviors. It cites the efficacy of the activity and the combined activity and diet programs in improving the movement skill proficiency of obese children. It further notes the efficacy of the three programs in lessening time spent in screen behaviors.

The article presents the study on combining the accelerometry and human resource (HR) for evaluating the physical activity (PA) of preschoolers in Germany. It states that the study aims for early screening and intervention evaluation .The study were conducted on thirty-three children from preschools using Activity Rating Scale (CARS) and receiver operating characteristics. It notes that using accelerometry and HR has correctly classified the moderate-to-vigorous PA (MVPA) in males and females. It also mentions that HR and accelerometry yields an accurate MVPA by perform less in classifying sedentary behavior (SB).