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Summer day camps (SDCs) serve over 14 million children in the U.S. and are well-positioned to help children accumulate the guideline of 60 min per day (60 min/d) of moderate-to-vigorous physical activity (MVPA). The purpose of this study was to evaluate a multi-component intervention to increase the percentage of children meeting 60 min/d of MVPA. Twenty SDCs serving 3524 children (7.9 yrs., 46.2% girls, 66.1% non-Hispanic Black) participated in a 4-summer non-randomized two-group intervention. Children's accelerometer-derived MVPA was collected using accelerometers worn on the non-dominant wrist. SDCs were assigned to either 2 summers of intervention (n = 10, no intervention summer 2015, intervention summer 2016 and 2017) or 1 summer of intervention (n = 10, no intervention summer 2015 and 2016, intervention summer 2017). The final summer (July 2018) was a no intervention follow-up. Multilevel mixed effects regression models estimated changes in percent of children meeting 60 min/d of MVPA. Across all summers and SDCs, children accumulated an average of 89.2 min/day (±22.5) of MVPA. The likelihood of meeting the 60 min/d MVPA guideline was not different during intervention versus baseline summers for boys or girls (p > 0.05). Girls and boys were 3.5 (95CI = 1.5, 8.1) and 3.7 (95CI = 1.6, 8.4) times more likely to meet the 60 min/d guideline during intervention summers versus follow-up, respectively. The intervention was not successful at increasing the percentage of children meeting the 60 min/d MVPA guideline. However, children attending SDCs accumulated substantial amounts of MVPA thus efforts should focus on making SDCs an accessible setting for all children., (© 2020 The Authors.)

Purpose: To evaluate the potential of a year-round school calendar (180-day school year distributed across 12 months) as an intervention compared to a traditional school calendar (180-day school year distributed across 9 months) for mitigating children's weight gain and fitness loss via a natural experiment., Methods: Height, weight, and cardiorespiratory fitness (CRF) (i.e., Fitnessgram Progressive Aerobic Cardiovascular Endurance Run) were measured in children (5-12 years old) in 3 schools (2 traditional, 1 year-round, n  = 990 students, age = 8.6 ± 2.4 years, 53.1% male, 68.9% African American) from 1 school district. Structure (represented by the presence of a school day) was the independent variable. Changes in body mass index (BMI), age- and sex-specific BMI z-scores (zBMI), BMI percentile, percent of overweight or obese children, and CRF (Progressive Aerobic Cardiovascular Endurance Run laps completed) were assessed for summer 2017 (May-August 2017), school year 2017/2018 (August 2017-May 2018), and summer 2018 (May-August 2018). Primary analyses examined the overall change in weight and CRF from summer 2017 until summer 2018 via multilevel mixed effects regression, with group (traditional vs. year-round calendar), time, and a group-by-time interaction as the independent variables. Secondary regression analyses estimated differences in change within and between groups during each time period, separately., Results: Year-round students gained less BMI (difference in ∆ = -0.44, 95% confidence interval (CI): -0.67 to -0.03) and less CRF (difference in ∆ = -1.92, 95%CI: -3.56 to -0.28) than students attending a traditional school overall. Compared with traditional students, during both summers, year-round students gained less BMI (summer 2017 difference in ∆ = -0.15, 95%CI: -0.21 to -0.08; summer 2018 difference in ∆ = -0.16, 95%CI: -0.24 to -0.07) and zBMI (summer 2017 difference in ∆ = -0.032, 95%CI: -0.050 to -0.010; summer 2018 difference in ∆ = -0.033, 95%CI: -0.056 to -0.009), and increased CRF (summer 2017 difference in ∆ = 0.40, 95%CI: 0.02-0.85; summer 2018 difference in ∆ = 0.23, 95%CI: -0.25 to 0.74). However, the opposite was observed for the school year, with traditional students gaining less BMI and zBMI and increasing CRF compared with year-round students (difference in BMI ∆ = 0.05, 95%CI: 0.03-0.07; difference in zBMI ∆ = 0.012, 95%CI: 0.005-0.019; difference in Progressive Aerobic Cardiovascular Endurance Run laps ∆ = -0.43, 95%CI: -0.58 to -0.28)., Conclusion: The year-round school calendar had a small beneficial impact on children's weight status but not CRF. It is unclear if this benefit to children's weight would be maintained because gains made in the summer were largely erased during the school year. Trajectories of weight and CRF gain/loss were consistent with the structured days hypothesis., (© 2019 Published by Elsevier B.V. on behalf of Shanghai University of Sport.)

Purpose : To compare children's energy expenditure (EE) levels during object projection skill performance (OPSP; e.g., kicking, throwing, striking) as assessed by hip- and wrist-worn accelerometers. Method : Forty-two children (female n = 20, M age = 8.1 ± 0.8 years) performed three, nine-minute sessions of kicking, over-arm throwing, and striking at performance intervals of 6, 12, and 30 seconds. EE was estimated using indirect calorimetry (COSMED k4b2) and accelerometers (ActiGraph GT3X+) worn on three different locations (hip, dominant-wrist, and non-dominant-wrist) using four commonly used cut-points. Bland-Altman plots were used to analyze the agreement in EE estimations between accelerometry and indirect calorimetry (METS). Chi-square goodness of fit tests were used to examine the agreement between accelerometry and indirect calorimetry. Results : Hip- and wrist-worn accelerometers underestimated EE, compared to indirect calorimetry, during all performance conditions. Skill practice at a rate of two trials per minute resulted in the equivalent of moderate PA and five trials per minute resulted in vigorous PA (as measured by indirect calorimetry), yet was only categorized as light and/or moderate activity by all measured forms of accelerometry. Conclusion : This is one of the first studies to evaluate the ability of hip- and wrist-worn accelerometers to predict PA intensity levels during OPSP in children. These data may significantly impact PA intervention measurement strategies by revealing the lack of validity in accelerometers to accurately predict PA levels during OPSP in children.

Objectives: To describe the associations of income and race with obesogenic behaviors and % body fat among a large sample of U.S. children and adolescents., Design: Data were obtained from the 2003-2004 and 2005-2006 National Health and Nutritional Examination Survey. Multiple linear regression models and interactions were used to examine the associations of moderate-to-vigorous physical activity (MVPA), sedentary time, diet quality, and screen-time with income-to-poverty ratio and race. Separate stratified analyses explored associations among individual obesogenic behaviors within race and income groups., Results: This study included children and adolescents (n = 3551, mean = 13.1 years, SD = 3.9 years) who were 37% Hispanic, 27% White, and 35% Black. Overall, Hispanic children/adolescents had significantly higher levels of adiposity (3.6, 95 CI = 0.9, 6.3) than white children and adolescents. Medium-income children and adolescents engaged in less MVPA (- 3.3 min, 95 CI = - 5.1, - 1.5), had poorer diet quality (- 1.1, 95 CI = - 1.9, - 0.2), and used screens less (- 33.9 min, 95 CI = - 45.4, - 22.4) than children and adolescents from low-income households. High-income children and adolescents also engaged in less MVPA (- 3.1 min, 95 CI = - 5.5, - 0.7) and used screens less (- 62.9 min, 95 CI = - 78.3, - 47.4) than children and adolescents from low-income households. However, there were significant race/ethnicity-by-income interactions for high-income Hispanic children and adolescents with diet quality (- 3.5 HEI-2010 score, 95 CI = - 6.6, - 0.4) and screen time (66.9 min, 95 CI = 24.7, 109.0). There was also a significant race/ethnicity-by-income interaction for the screen-time of Black children and adolescents from medium (33.8 min, 95% CI 0.2, 67.3) and high (75.8 min, 95% CI 34.7, 117.0) income households., Conclusions: There appears to be a complex relationship that varies by race/ethnicity between income, obesogenic behaviors, and adiposity levels among children and adolescents. More work is needed to identify the behavioral mechanisms that are driving disparate rates of overweight and obesity among minority children and those from low-income households.

Background/objectives: Overweight and obesity (OWOB) is a global epidemic. Adults and adolescents from low-income households are at higher risk to be OWOB. This study examined the relationship between income and OWOB prevalence in children and adolescents (518 years) in the United States (US) within and across race/ethnicities, and changes in this relationship from 1971 to 2014., Subjects/methods: A meta-analysis of a nationally representative sample (N = 73,891) of US children and adolescents drawn from three datasets (i.e., National Health and Nutrition Examination Survey, National Longitudinal Survey of Youth, & the Early Childhood Longitudinal Program) which included 14 cross-sectional waves spanning 1971-2014 was conducted. The exposure was household income-to-poverty ratio (low income = 0.00-1.00, middle income = 1.01-4.00, high income >4.00) with prevalence of overweight or obesity (body mass index ≥ 85th percentile) as the outcome., Results: Children and adolescents from middle-income and high-income households were 0.78 (95% CI = 0.72, 0.83) and 0.68 (95% CI = 0.59, 0.77) times as likely to be OWOB compared to children and adolescents in low-income households. Separate analyses restricted to each racial/ethnic group showed children and adolescents from middle- and high-income households were less likely to be OWOB compared to their low-income peers within the White, Hispanic, and Other race/ethnic groups. Children and adolescents from low-income households who were Black were not more likely to be OWOB than their high- and middle-income counterparts. Analyses within each income stratum indicated that race/ethnicity was not related to the prevalence of OWOB in low-income households. However, racial/ethnic differences in OWOB were evident for children and adolescents in middle- and high-income households. Disparities in the prevalence of OWOB between low-income children and adolescents and their middle- and high-income counterparts have increased from 1971 to 2014., Conclusions: Income and OWOB are related in US children and adolescents. Racial/ethnic differences in the prevalence of OWOB emerge in middle- and high-income households. Disparities in OWOB prevalence are growing.

This study examined the impact of an existing 7-week summer learning program on children's weight status and cardiorespiratory fitness (CRF)., Methods: Using an observational repeated measures within-subjects design, children's (N = 20 mean age = 6.35; 45% female; 80% African American) height, weight, and CRF (i.e., Fitnessgram PACER), were measured during the first and final week of the seven week program. Descriptive statistics were calculated for all variables. Median regression analysis examined estimated the differences in BMI zscore, overweight and obesity prevalence, and CRF during the first week (baseline) compared to the final week (outcome)., Results: Of those enrolled initially in the program, 77% attended for more than 4 weeks. When controlling for attendance and sex, no statistically significant changes were observed for, median zBMI (pre: 0.12, post: 0.11) or CRF (pre: 10, post: 13.5 PACER laps). All children except for one maintained the same weight status (e.g. normal weight, overweight) from baseline to outcome. A total of 12 participants increased or maintained the number of PACER laps completed, while 8 participants' PACER laps decreased., Conclusion: The results of this natural experiment provides preliminary evidence that participation in a structured summer program can potentially mitigate unhealthy weight gains and fitness loss over the summer for some children. Future studies with larger more representative samples are needed to establish the impact of structured summer programming on children's CRF and weight status., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: A recent meta-analysis reported that exercise interventions are effective for promoting weight loss in adolescents with overweight-obesity. However, the meta-analysis did not investigate whether there is an optimal exercise dose for promoting weight loss in overweight and obese adolescents. A common method of expressing exercise dose is the calculation of metabolic equivalents (METs), expressed as MET-h/week., Objectives: The objective of this study was to determine the association between exercise dose (MET-h/week) and weight loss [body weight, body mass index (BMI)] in adolescents with overweight-obesity., Data Sources: Trials included in the original meta-analysis were extracted, and a subsequent search to identify studies published between May 2015 and May 2018 was conducted. The search included electronic databases (PubMed, Web of Science SPORTDiscus, Google Scholar) and the reference lists of eligible articles and relevant reviews., Study Selection: The inclusion criteria were as follows: (i) randomized controlled trial; (ii) structured exercise intervention, alone or combined with other intervention components; (iii) control group received no structured exercise or behavioral modification designed to increase physical activity; (iv) participants overweight or obese (BMI ≥ 85th percentile); and (v) participants aged between 10 and 19 years., Appraisal and Synthesis Methods: Fifteen trials were extracted from the original meta-analysis. The current search identified an additional five trials (three articles). Data from 20 trials (16 articles) involving 1091 participants (54% female, 17% not reported) were included in the analysis. Effect sizes were reported as mean difference, and random effects meta-regression quantified the association between exercise dose and weight loss. Study quality was assessed using a modified Jadad's scale., Results: Total body weight change (decrease) ranged from - 2.7 to 19.3 (median 2.5) kg, and BMI change (decrease) ranged from - 1.6 to 6.3 (median 0.9) kg/m 2 . MET-h/week ranged from 5.4 to 36.0 (median 6.0). Each MET-h/week was associated with a 0.13 kg/m 2 (95% confidence interval [CI] 0.08-0.19) and 0.33 kg (95% CI 0.08-0.59) decrease in BMI and body weight, respectively., Limitations: The prescribed exercise dose for the majority of trials was low. As such, we were unable to discern whether there was an optimal exercise dose for weight loss (i.e., if the association between dose and weight loss was non-linear). Additionally, most trials had small sample sizes (median n = 34) and 17 trials had methodological limitations., Conclusions: Each MET-h/week was associated with a 0.13 kg/m 2 and 0.33 kg decrease in BMI and body weight, respectively. While this relationship appears to be linear, i.e., no optimal exercise dose, it should be emphasized that the exercise prescription dose for the majority of trials was low. Subsequent trials, with greater exercise dosage, are required to determine whether there is an 'optimal' dose for promoting weight loss in adolescents with overweight-obesity. However, the current findings lend support to the use of exercise prescription for promoting weight loss and improving health outcomes in this population.

Background: Evidence consistently shows children in the United States gain 3 to 5 times more weight during summer vacation (∼2.5 months) compared to the 9-month school year. The purpose of this study is to examine within-child differences in 4 obesogenic behaviors (physical activity [PA], sedentary/screen-time, diet, and sleep) during school versus summer., Methods: We used a repeated-measures within-subjects design. Children (N = 30 mean age = 8.2 years; 57% female; 37% overweight/obese; 100% African American) wore accelerometers on the nondominant wrist for 24 hr/d over 9 consecutive days during school and summer of 2016 to capture PA, sedentary time, and sleep. Parents completed a daily diary to report bed/wake times, diet, and screen-time of their child each day. Mixed-effect models compared summer and school behaviors., Results: Children spent more time sedentary (69% vs 67% of wake wear time), less time in light PA (25% vs 23% of wake wear time), had higher screen-time (242 vs 123 minutes/day), slept longer (428 vs 413 minutes/night), and consumed more sugar-based foods (6 days vs 2.5 days/week) and fruit (7 days vs 4.7 days/week) during summer compared to school (p < .05)., Conclusion: Initial evidence suggests children are displaying multiple unfavorable obesogenic behaviors during summer compared to school that may contribute to accelerated weight gain during summer., (© 2018, American School Health Association.)

Background: The objective of this paper is to derive a wrist-placed cut-point threshold for distinguishing sedentary behaviors from light-intensity walking using the ActiGraph GT3X+ in children., Methods: This study employed a cross-sectional study design, typically used in measurement-related studies. A sample of 167 children, ages 5⁻11 years (mean ± SD: 8.0 ± 1.8 years), performed up to eight seated sedentary activities while wearing accelerometers on both wrists. Activities included: reading books, sorting cards, cutting and pasting, playing board games, eating snacks, playing with tablets, watching TV, and writing. Direct observation verified sedentary behavior from light activity. Receiver operator characteristic (ROC) analyses were used to determine optimal cut-point thresholds. Quantile regression models estimated differences between dominant and non-dominant placement., Results: The optimal cut-point threshold for the non-dominant wrist was 203 counts/5 s with sensitivity, specificity, and area under the curve (AUC) of 71.56, 70.83, and 0.72, respectively. A 10-fold cross-validation revealed an average AUC of 0.70. Statistically significant ( p ≤ 0.05) differences in median counts ranging from 7 to 46 counts/5 s were found between dominant and non-dominant placement in five out of eight sedentary activities, with the dominant wrist eliciting higher counts/5 s., Conclusion: Results from this study support the recommendation to place accelerometers on the non-dominant wrist to minimize "noise" during seated sedentary behaviors.

This study examined the initial effects of a participatory-based, competency-/skill-building professional development workshop for physical education (PE) teachers on the use of physical activity (PA) promotion practices (e.g., eliminating lines, small-sided games) and students' moderate-to-vigorous physical activity (MVPA). A total of 823 students (52.8% boys) wore accelerometers at baseline (fall 2015) and outcome (spring 2016) on PE and non-PE days. The System for Observing Fitness Instruction Time+ measured changes in PA promotion practices. Teachers ( n = 9) attended a 90-minute workshop prior to outcome data collection. Mixed-model linear regressions estimated changes in teacher practices and students' MVPA. Three of the nine targeted PA promotion practices changed in the desired direction (i.e., p < .05; increased motor content and lessons taught outdoors, reduced activities with lines), with three more teacher practices trending in the desired direction (i.e., reduced management time and activities with elimination, increased small-sided games). During PE, boys and girls increased MVPA by 2.0 (95% confidence interval [1.1, 3.0]), and 1.3 (95% confidence interval [0.5-2.0]) minutes, respectively. However, there were no statistically significant changes in boys' or girls' MVPA during the school day. Greater implementation of promotion practices by the PE teachers was associated with boys', but not girls', MVPA during PE. Girls in high- and low-implementing teachers' lessons experienced increases in MVPA, suggesting that even small changes in PA promotion practices can increase girls' MVPA during PE. Overall, the workshops were effective at increasing teachers' PA promotion and students' MVPA in PE. Other school-based strategies that complement and extend efforts targeting PE are recommended to increase children's total daily PA.

Limited information is available on the cost-effectiveness of interventions to achieve healthy eating and physical activity policies in afterschool programs (ASPs). The objective of this study is to present the costs associated with a comprehensive intervention in ASPs. Intervention delivery inputs (IDIs) associated with a group randomized delayed treatment controlled trial involving 20 ASPs serving >1700 children (5-12yrs) were catalogued prospectively across 2-years (2014-2015). IDIs, analyzed 2015, were expressed as increases in per-child per-week enrollment fees based on a 34-week school year in US$. Total IDIs for year-1 were $15,058 (+$0.58/child/week enrollment fee). In year-2, total costs were $13,828 (+$0.52/child/week) for the delayed group and $7916 (+$0.30/child/week) for the immediate group, respectively. Site leader and staff hourly wages represented 11-17% and 45-46% of initial training costs; travel and trainer wages represented 31-42% and 50-58% of booster costs. Overall, a 1% increase in boys and girls, separately, accumulating 30 mins/d of moderate-to-vigorous physical activity ranged from $0.05 to $0.26/child/week, while a one-day increase in serving a fruit/vegetable or water, or not serving sugar-added foods/beverages ranged from $0.16 to $0.87/child/week. Costs associated with implementing the intervention were minimal. Additional efforts to reduce costs and improve intervention effectiveness are necessary., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The YMCA of USA has adopted Healthy Eating and Physical Activity (HEPA) Standards for its afterschool programs (ASPs). Little is known about strategies YMCA ASPs are implementing to achieve Standards and these strategies' effectiveness., Aims: (1) Identify strategies implemented in YMCA ASPs and (2) evaluate the relationship between strategy implementation and meeting Standards., Method: HEPA was measured via accelerometer (moderate-to-vigorous-physical-activity [MVPA]) and direct observation (snacks served) in 20 ASPs. Strategies were identified and mapped onto a capacity building framework ( Strategies To Enhance Practice [STEPs]). Mixed-effects regression estimated increases in HEPA outcomes as implementation increased. Model-implied estimates were calculated for high (i.e., highest implementation score achieved), moderate (median implementation score across programs), and low (lowest implementation score achieved) implementation for both HEPA separately., Results: Programs implemented a variety of strategies identified in STEPs. For every 1-point increase in implementation score 1.45% (95% confidence interval = 0.33% to 2.55%, p ≤ .001) more girls accumulated 30 min/day of MVPA and fruits and/or vegetables were served on 0.11 more days (95% confidence interval = 0.11-0.45, p ≤ .01). Relationships between implementation and other HEPA outcomes did not reach statistical significance. Still regression estimates indicated that desserts are served on 1.94 fewer days (i.e., 0.40 vs. 2.34) in the highest implementing program than the lowest implementing program and water is served 0.73 more days (i.e., 2.37 vs. 1.64)., Conclusions: Adopting HEPA Standards at the national level does not lead to changes in routine practice in all programs. Practical strategies that programs could adopt to more fully comply with the HEPA Standards are identified.

Objectives: Different accelerometer cutpoints used by different researchers often yields vastly different estimates of moderate-to-vigorous intensity physical activity (MVPA). This is recognized as cutpoint non-equivalence (CNE), which reduces the ability to accurately compare youth MVPA across studies. The objective of this research is to develop a cutpoint conversion system that standardizes minutes of MVPA for six different sets of published cutpoints., Design: Secondary data analysis., Methods: Data from the International Children's Accelerometer Database (ICAD; Spring 2014) consisting of 43,112 Actigraph accelerometer data files from 21 worldwide studies (children 3-18 years, 61.5% female) were used to develop prediction equations for six sets of published cutpoints. Linear and non-linear modeling, using a leave one out cross-validation technique, was employed to develop equations to convert MVPA from one set of cutpoints into another. Bland Altman plots illustrate the agreement between actual MVPA and predicted MVPA values., Results: Across the total sample, mean MVPA ranged from 29.7MVPAmind(-1) (Puyau) to 126.1MVPAmind(-1) (Freedson 3 METs). Across conversion equations, median absolute percent error was 12.6% (range: 1.3 to 30.1) and the proportion of variance explained ranged from 66.7% to 99.8%. Mean difference for the best performing prediction equation (VC from EV) was -0.110mind(-1) (limits of agreement (LOA), -2.623 to 2.402). The mean difference for the worst performing prediction equation (FR3 from PY) was 34.76mind(-1) (LOA, -60.392 to 129.910)., Conclusions: For six different sets of published cutpoints, the use of this equating system can assist individuals attempting to synthesize the growing body of literature on Actigraph, accelerometry-derived MVPA., (Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Background: Staff in settings that care for children struggle to implement standards designed to promote moderate-to-vigorous physical activity (MVPA), suggesting a need for effective strategies to maximize the amount of time children spend in MVPA during scheduled PA opportunities. The purpose of this study was to compare the MVPA children accumulate during commonly played games delivered in their traditional format versus games modified according to the LET US Play principles., Methods: Children (K-5th) participated in 1-hour PA sessions delivered on non-consecutive days (summer 2014). Using a randomized, counterbalanced design, one of the six games was played for 20min using either traditional rules or LET US Play followed by the other strategy with a 10min break in between. Physical activity was measured via accelerometry. Repeated-measures, mixed-effects regression models were used to estimate differences in percent of time spent sedentary and in MVPA., Results: A total of 267 children (age 7.5years, 43% female, 29% African American) participated in 50, 1-hour activity sessions. Games incorporating LET US Play elicited more MVPA from both boys and girls compared to the same games with traditional rules. For boys and girls, the largest MVPA difference occurred during tag games (+20.3%). The largest reduction in the percent of time sedentary occurred during tag games (boys -27.7%, girls -32.4%). Overall, the percentage of children meeting 50% time in MVPA increased in four games (+18.7% to +53.1%)., Conclusion: LET US Play led to greater accumulation of MVPA for boys and girls, and can increase the percent of children attaining the 50% of time in MVPA standard., (Copyright © 2015 Elsevier Inc. All rights reserved.)