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Objectives: To examine the association between physical activity, sedentary time, and physical fitness with the shapes of subcortical brain structures in children with overweight/obesity. Further, we analyzed whether differences in the shapes of subcortical brain structures were related to intelligence. We hypothesized that those children with higher physical activity levels, lower sedentary time, and better fitness, would show greater expansion of the brain regions analyzed, and these expansions would be associated with higher intelligence. Study Design: 100 children (10.0 ± 1.1 years, 40 girls) were included in the analyses. Physical activity and sedentary time were measured by accelerometry, and physical fitness was evaluated by a fitness battery. Shapes of subcortical brain structures were assessed by magnetic resonance imaging. Intelligence was measured by the Kaufmann Brief Intelligence test. Results: Physical activity was related to expansion of the right/left pallidum, right/left putamen, and right thalamus (p < 0.05). Higher sedentary time was related to contraction of the left thalamus and right nucleus accumbens (p < 0.05). Higher levels of cardiorespiratory fitness were associated with expansion of the right amygdala (p = 0.022). Greater strength in the upper‐limb was related to expansion of the right/left pallidum and the left nucleus accumbens (p < 0.038), and contraction of the left amygdala (p = 0.030). Better speed‐agility was associated with expansion of the left nucleus accumbens (p = 0.036). Physical activity‐ and fitness‐related expansion of the right pallidum was associated with higher intelligence (all p < 0.05). Conclusion: Physical activity, sedentary time, and physical fitness were significantly related to the shapes of subcortical brain structures, which in turn were related to intelligence in children with overweight/obesity. [ABSTRACT FROM AUTHOR]

Abstract Background In England, the onset of COVID-19 and a rapidly increasing infection rate resulted in a lockdown (March-June 2020) which placed strict restrictions on movement of the public, including children. Using data collected from children living in a multi-ethnic city with high levels of deprivation, this study aimed to: (1) report children’s self-reported physical activity (PA) during the first COVID-19 UK lockdown and identify associated factors; (2) examine changes of children’s self-reported PA prior to and during the first UK lockdown. Methods This study is part of the Born in Bradford (BiB) COVID-19 Research Study. PA (amended Youth Activity Profile), sleep, sedentary behaviours, daily frequency/time/destination/activity when leaving the home, were self-reported by 949 children (9–13 years). A sub-sample (n = 634) also self-reported PA (Physical Activity Questionnaire for Children) pre-pandemic (2017-February 2020). Univariate analysis assessed differences in PA between sex and ethnicity groups; multivariable logistic regression identified factors associated with children’s PA. Differences in children's levels of being sufficiently active prior to and during the lockdown were examined using the McNemar test; and multivariable logistic regression was used to identify factors explaining change. Results During the pandemic, White British (WB) children were more sufficiently active (34.1%) compared to Pakistani Heritage children (PH) (22.8%) or ‘Other’ ethnicity children (O) (22.8%). WB children reported leaving the home more frequently and for longer periods than PH and O children. Modifiable variables related to being sufficiently active were frequency, duration, type of activity, and destination away from the home environment. There was a large reduction in children being sufficiently active during the first COVID-19 lockdown (28.9%) compared to pre-pandemic (69.4%). Conclusions Promoting safe extended periods of PA everyday outdoors is important for all children, in particular for children from ethnic minority groups. Children’s PA during the first COVID-19 UK lockdown has drastically reduced from before. Policy and decision makers, and practitioners should consider the findings in order to begin to understand the impact and consequences that COVID-19 has had upon children’s PA which is a key and vital behaviour for health and development.

This study examined the longitudinal associations between five physical activity (PA) motives and moderate-to-vigorous PA (MVPA) across a 5-year period spanning late childhood to middle adolescence. METHODS: Data (n = 937; 55% girls; mean age = 10.33 years) were drawn from the Monitoring Activities for Teenagers to Comprehend their Habits study. PA motives and MVPA were assessed 15 times over the course of 5 years. Measurement invariance for the Motives for Physical Activity Measure-Revised (MPAM-R) questionnaire was established, and sex-stratified mixed-effects regression models were analysed. MVPA increased until a mean age of 12.18 years for girls and 12.89 years for boys before decreasing through the final assessment. From late childhood to middle adolescence, for boys, enjoyment motives were positively (β(95% CI) = 6.14(3.86–8.43)), while fitness motives were negatively (β(95% CI) = −4.80(−8.0, −1.59)) associated with MVPA. Whereas, for girls, competence motives were positively β(95% CI) = 3.44(1.59–5.28)) associated with MVPA Boys may benefit from PA interventions, if these were primarily aimed at increasing ones' enjoyment, whereas developing a girl's competence may provide greater contributions to a girl's future PA behaviours. PA interventions should avoid promoting the desire to be active to improve fitness, particularly among boys. [ABSTRACT FROM AUTHOR]

Background: In England, the onset of COVID-19 and a rapidly increasing infection rate resulted in a lockdown (March-June 2020) which placed strict restrictions on movement of the public, including children. Using data collected from children living in a multi-ethnic city with high levels of deprivation, this study aimed to: (1) report children's self-reported physical activity (PA) during the first COVID-19 UK lockdown and identify associated factors; (2) examine changes of children's self-reported PA prior to and during the first UK lockdown. Methods: This study is part of the Born in Bradford (BiB) COVID-19 Research Study. PA (amended Youth Activity Profile), sleep, sedentary behaviours, daily frequency/time/destination/activity when leaving the home, were self-reported by 949 children (9–13 years). A sub-sample (n = 634) also self-reported PA (Physical Activity Questionnaire for Children) pre-pandemic (2017-February 2020). Univariate analysis assessed differences in PA between sex and ethnicity groups; multivariable logistic regression identified factors associated with children's PA. Differences in children's levels of being sufficiently active prior to and during the lockdown were examined using the McNemar test; and multivariable logistic regression was used to identify factors explaining change. Results: During the pandemic, White British (WB) children were more sufficiently active (34.1%) compared to Pakistani Heritage children (PH) (22.8%) or 'Other' ethnicity children (O) (22.8%). WB children reported leaving the home more frequently and for longer periods than PH and O children. Modifiable variables related to being sufficiently active were frequency, duration, type of activity, and destination away from the home environment. There was a large reduction in children being sufficiently active during the first COVID-19 lockdown (28.9%) compared to pre-pandemic (69.4%). Conclusions: Promoting safe extended periods of PA everyday outdoors is important for all children, in particular for children from ethnic minority groups. Children's PA during the first COVID-19 UK lockdown has drastically reduced from before. Policy and decision makers, and practitioners should consider the findings in order to begin to understand the impact and consequences that COVID-19 has had upon children's PA which is a key and vital behaviour for health and development. [ABSTRACT FROM AUTHOR]

Introduction: Physical education (PE) can contribute to total daily physical activity (PA) among children. In consequence, the Spanish Ministry of Education, Culture and Sport has developed 16 teaching units focused on increasing PA levels during PE lessons, called Unidades Didácticas Activas (UDA; Active Teaching Units). Objectives: The goal of this study was to compare whether children participating in UDA lessons spent more time in moderate-to-vigorous physical activity (MVPA) than children participating in traditional lessons. Design: Quasi-experimental design. Methods: A total of 355 children (8–9 years old, 53.9% boys) from 7 schools in Granada participated in the study. Students were divided into two groups: a traditional PE group (n = 204) and a UDA group (n = 151). Time spent in MVPA was assessed using tri-axial accelerometers. Results: Time spent in MVPA was higher in the group engaged in the UDA lessons compared to the group that received traditional lessons (13.6 vs 15.2 minutes, p =.021, Standard Error = 0.27). The percentage of children who met international MVPA recommendations was similar for both groups (UDAs: 12.7% and traditional: 13.2%, p =.504). Conclusions: UDA lessons and their methodology favoured greater participation in MVPA compared to a traditional PE approach. It will be important to change PE methodology (including duration, frequency and focus) to achieve MVPA goals. [ABSTRACT FROM AUTHOR]

International physical activity guidelines suggest that adults should engage in at least 150 min of moderate-intensity aerobic physical activity per week, at least 75 min of vigorous-intensity aerobic physical activity throughout the week, or an equivalent combination of moderate- and vigorous-intensity activity. This seems to imply that little or no health benefits can be reaped from light-intensity physical activity (LPA; e.g., walking slowly, shopping, walking a dog, lifting lightweight objects, and doing household chores). However, an increasing body of evidence indicates that LPA may provide health benefits for adults and older adults. This review examined several crucial aspects of LPA and health and assessed whether the health benefits of LPA for adults aged 18 or older are underestimated. The following procedures were implemented to review the evidence of device-based measurements of LPA and health. First, the country profiles of adults performing LPA were described. Second, evidence obtained through systematic reviews and meta-analyses was examined to explore how LPA relates to mortality, morbidity, and other health outcomes. Finally, research topics regarding whether the health benefits of LPA for adults are underestimated were evaluated. In summary, evidence from systematic reviews and metaanalyses based on device-based assessment of LPA supports the health benefits of LPA for adults, which are independent of the effects of moderate-to-vigorous-intensity physical activity. Although some studies have suggested that adults can achieve health benefits by engaging in LPA for at least 6 hours per day, further research is needed to confirm this finding. [ABSTRACT FROM AUTHOR]

Background: Policies to require afterschool programs (ASPs, 3 PM to 6 PM) to provide children a minimum of 30 minutes of moderate-to-vigorous physical activity (MVPA) exist. With few low-cost, easy-to-use measures of MVPA available to the general public, ASP providers are limited in their ability to track progress toward achieving this policy-goal. Pedometers may fill this gap, yet there are no step-count guidelines for ASPs linked to 30 minutes of MVPA. Methods: Steps and accelerometer estimates of MVPA were collected concurrently over multiple days on 245 children (8.2 years, 48% boys, BMI-percentile 68.2) attending 3 community-based ASPs. Random intercept logit models and receiver operating characteristic (ROC) analyses were used to identify a threshold of steps that corresponded with attaining 30 minutes of MVPA. Results: Children accumulated an average of 2876 steps (standard error [SE] 79) and 16.1 minutes (SE0.5) of MVPA over 111 minutes (SE1.3) during the ASP. A threshold of 4600 steps provided high specificity (0.967) and adequate sensitivity (0.646) for discriminating children who achieved the 30 minutes of MVPA; 93% of the children were correctly classified. The total area under the curve was 0.919. Children accumulating 4600 steps were 25times more likely to accumulate 30 minutes of MVPA. Conclusions: This step threshold will provide ASP leaders with an objective, low-cost, easy-to-use tool to monitor progress toward policy-related goals. [ABSTRACT FROM AUTHOR]

Background Heart rate variability (HRV) is considered to explain improvements in cardiovascular health accrued by physical activity (PA) and cardiorespiratory fitness (CRF) over and above traditional cardiovascular risk factors. Objective To systematically address associations between HRV, PA and CRF in children and adolescents. Data sources Medline, EMBASE, SportDISCUS and CINAHL Plus were searched on 5th September 2015 and updated on 4th August 2016. Eligibility criteria Observational studies comparing HRV in different groups of PA and CRF, and/or studies investigating associations between PA, CRF and HRV. Sports practices and PA intensities were also included. The square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD), the spectral density in the high (HF) and low (LF) frequency, and the LF/HF ratio were included. Risk of bias was assessed using the adapted Newcastle-Ottawa Scale (NOS). Results Heterogeneity exists in the assessment of the exposures and outcomes, and sample characteristics. Risk of bias (NOS) was observed in most of the studies. Studies with low risk of bias showed positive associations between moderate-to-vigorous PA and RMSSD. The evidence for the associations between PA and frequency indices is weak. Similarly, the evidence for the association between CRF and HRV is weak. Conclusions Despite the heterogeneity in the studies, moderate-to-vigorous PA is positively associated with RMSSD, but less clear are the associations between CRF and HRV, as well as other PA intensities. Further research is needed to clarify the role of PA and CRF on HRV in children and adolescents. [ABSTRACT FROM AUTHOR]

Background: Physical activity interventions targeting children and adolescents (=18 years) often focus on complex intra- and inter-personal behavioral constructs, social-ecological frameworks, or some combination of both. Recently published meta-analytical reviews and large-scale randomized controlled trials have demonstrated that these intervention approaches have largely produced minimal or no improvements in young people's physical activity levels. Discussion: In this paper, we propose that the main reason for previous studies' limited effects is that fundamental mechanisms that lead to change in youth physical activity have often been overlooked or misunderstood. Evidence from observational and experimental studies is presented to support the development of a new theory positing that the primary mechanisms of change in many youth physical activity interventions are approaches that fall into one of the following three categories: (a) the expansion of opportunities for youth to be active by the inclusion of a new occasion to be active, (b) the extension of an existing physical activity opportunity by increasing the amount of time allocated for that opportunity, and/or (c) the enhancement of existing physical activity opportunities through strategies designed to increase physical activity above routine practice. Their application and considerations for intervention design and interpretation are presented. Summary: The utility of these mechanisms, referred to as the Theory of Expanded, Extended, and Enhanced Opportunities (TEO), is demonstrated in their parsimony, logical appeal, support with empirical evidence, and the direct and immediate application to numerous settings and contexts. The TEO offers a new way to understand youth physical activity behaviors and provides a common taxonomy by which interventionists can identify appropriate targets for interventions across different settings and contexts. We believe the formalization of the TEO concepts will propel them to the forefront in the design of future intervention studies and through their use, lead to a greater impact on youth activity behaviors than what has been demonstrated in previous studies. [ABSTRACT FROM AUTHOR]

National and state organizations have developed policies calling upon afterschool programs (ASPs, 3-6 pm) to serve a fruit or vegetable (FV) each day for snack, while eliminating foods and beverages high in added-sugars, and to ensure children accumulate a minimum of 30 min/d of moderate-to-vigorous physical activity (MVPA). Few efficacious and cost-effective strategies exist to assist ASP providers in achieving these important public health goals. This paper reports on the design and conceptual framework of Making Healthy Eating and Physical Activity (HEPA) Policy Practice in ASPs, a 3-year group randomized controlled trial testing the effectiveness of strategies designed to improve snacks served and increase MVPA in children attending community-based ASPs. Twenty ASPs, serving over 1800 children (6-12 years) will be enrolled and match-paired based on enrollment size, average daily min/d MVPA, and days/week FV served, with ASPs randomized after baseline data collection to immediate intervention or a 1-year delayed group. The framework employed, STEPs (Strategies To Enhance Practice), focuses on intentional programming of HEPA in each ASPs' daily schedule, and includes a grocery store partnership to reduce price barriers to purchasing FV, professional development training to promote physical activity to develop core physical activity competencies, as well as ongoing technical support/assistance. Primary outcome measures include children's accelerometry-derived MVPA and time spend sedentary while attending an ASP, direct observation of staff HEPA promoting and inhibiting behaviors, types of snacks served, and child consumption of snacks, as well as, cost of snacks via receipts and detailed accounting of intervention delivery costs to estimate cost-effectiveness. [ABSTRACT FROM AUTHOR]

Background: It is difficult to compare accelerometer-derived estimates of moderate-to-vigorous physical activity (MVPA) between studies due to differences in data processing procedures. We aimed to evaluate the effects of accelerometer processing options on total and bout-accumulated time spent in MVPA in adults. Methods: 267 participants from the ProActive Trial provided 1236 days of valid physical activity (PA) data, collected using a 5-s epoch with ActiGraph GT1M accelerometers. We integrated data over 5-s to 60-s epoch lengths (EL) and applied two-level mixed effects regression models to MVPA time, defined using 1500 to 2500 counts/minute (cpm) cut-points (CP) and bout durations (BD) from 1 to 15 min. Results: Total MVPA time was lower on longer EL and higher CP (47 vs 26 min/day and 26 vs 5 min/day on 1500 vs 2500 cpm on 5-s and 60-s epoch, respectively); this could be approximated as MVPA = exp[2.197 + 0.279*log(CP) + 6.120*log(EL) - 0.869*log(CP)*log(EL)] with an 800 min/day wear-time. In contrast, EL was positively associated with time spent in bout-accumulated MVPA; the approximating equation being MVPA = exp[54.679 - 6.268*log(CP) + 6.387*log(EL) - 10.000*log(BD) - 0.162*log(EL)*log(BD) - 0.626*log(CP)*log(EL) + 1.033*log(CP)*log(BD)]. BD and CP were inversely associated with MVPA, with higher values attenuating the influence of EL. Conclusions: EL, CP and BD interact to influence estimates of accelerometer-determined MVPA. In general, higher CP and longer BD result in lower MVPA but the direction of association for EL depends on BD. Reporting scaling coefficients for these key parameters across their frequently used ranges would facilitate comparisons of population-level accelerometry estimates of MVPA. [ABSTRACT FROM AUTHOR]

Afterschool programs (3-6 p.m.) are positioned to play a critical role in combating childhood obesity. To this end, state and national organizations have developed policies related to promoting physical activity and guiding the nutritional quality of snacks served in afterschool programs. No conceptual frameworks, however, are available that describe the process of how afterschool programs will translate such policies into daily practice to reach eventual outcomes. Drawing from complex systems theory, this article describes the development of a framework that identifies critical modifiable levers within afterschool programs that can be altered and/or strengthened to reach policy goals. These include the policy environment at the national, state, and local levels; individual site, afterschool program leader, staff, and child characteristics; and existing outside organizational partnerships. Use of this framework and recognition of its constituent elements have the potential to lead to the successful and sustainable adoption and implementation of physical activity and nutrition policies in afterschool programs nationwide. [ABSTRACT FROM PUBLISHER]

Afterschool programs (3-6 pm, ASPs) represent a promising approach to promote physical activity (PA) and are positioned to make a substantial contribution to children’s overall daily PA. This article synthesizes both descriptive and intervention focused efforts aimed at describing/increasing PA within the ASP setting and outlines future directions for research. ASPs provide anywhere from 8 to 24 minutes of moderate-to-vigorous PA daily, with children accumulating between 2600 and 3200 steps per day. State and national organizations have developed policies related to PA in ASPs, but the limited available evidence indicates that ASPs are far from meeting PA policy goals. A total of 17 ASP PA intervention studies have been conducted, more than half (9/17) within ASPs that were initiated and developed by researchers. Based on the review of evidence, key strategies to increase PA include high-quality professional development training, allocating time in the ASP schedule for children to engage in sufficient amounts of PA, and tailoring the intervention to local conditions. Future directions should focus on evaluating these key strategies, conducting descriptive studies of common ASP characteristics nationally and their influence on children’s PA, evaluation/refinement of existing ASP PA curricula, cost-effectiveness of interventions, and identification of feasible PA policy goals. [ABSTRACT FROM PUBLISHER]

Abstract: Objectives: This study synthesized the published estimates of daily moderate-to-vigorous physical activity (MVPAd−1) of preschooler-age children (3–5years). Design: Meta-analysis of previously published studies reporting accelerometer-derived estimates of daily MVPA of preschoolers. Methods: A comprehensive literature review was conducted to identify studies published by March 2010 that reported daily minutes of accelerometer-derived MVPA in preschool-age children (3–5years). Random effects point estimates and 95% confidence intervals (95% CIs) were calculated based on study weighted means and standard deviations of raw accelerometer counts per minute (cpm) and reported minutes of MVPA and/or percentage of time spent in MVPAd−1. Results: 29 articles representing 6309 preschoolers were included. Overall, preschoolers engaged in 42.8min (95% CI 28.9–56.8) of MVPAd−1, and 54.4min (95% CI 29.9–78.9) and 45.4min (95% CI 25.2–65.6) for boys and girls separately. This translated into approximately 5.5% (95% CI 3.7–7.2%) of time spent in MVPAd−1, and 7.1% (95% CI 3.9–10.3%) for boys and 6.3% (95% CI 3.9–8.7%) for girls. Studies (76%) using ActiGraph accelerometers reported an average of 714cpm (95% CI 678–751), with boys and girls having 783cpm (95% CI 753–813) and 696cpm (95% CI 665–727), respectively. Conclusions: Interpretation of accelerometer-derived MVPA is confounded by differences in cutpoints applied within a study. Great care, therefore, should be taken when interpreting the activity levels of preschoolers to inform policy decisions, such as the development of physical activity guidelines. Hence, considerable attention is required to unify accelerometer-derived MVPA so that unbiased comparisons across studies can be made. [Copyright &y& Elsevier]

Background: Policies now recommend afterschool programs (ASP, 3–6pm) provide children a minimum amount of physical activity daily. We examined the extent to which children attending ASPs meet existing national and state-level policies that specify expected levels of physical activity (PA). Methods: Accelerometer-derived physical activity (light and moderate-to-vigorous, MVPA) of 253 children (5–13 years) was compared to policies that recommend varying amounts of PA children should achieve during an ASP. Results: The proportion of children achieving a policy ranged from 0.0% (California 60min MVPA and North Carolina 20% of daily program time devoted to MVPA), 1.2% (California 30min MVPA), to 48.2% (National Afterschool Association 30min light plus MVPA). Random effects logistic models indicated boys (odds ratio [OR] range 2.0 to 6.27) and children from a minority background (Black/Hispanic, OR range 1.87 to 3.98) were more likely to achieve a recommended level of physical activity, in comparison to girls and White children. Neither age nor BMI were related to achieving a policy. Conclusions: The PA of children attending ASP falls below policy recommended levels; however, these policies were developed in absence of data on expected PA levels during ASPs. Thus, concerted effort towards building a stronger ASP evidence-base for policy refinement is required. [Copyright &y& Elsevier]

Introduction: Physical activity (PA) may play a role in maintenance of cognitive function in both middle and older ages and prevention of outcomes such as dementia and Alzheimer's disease., Methods: Cross-sectional regression analyses were performed in Framingham Heart Study Third Generation (n = 1861) and Offspring (n = 909) cohort participants assessing the association of accelerometry-measured PA with cognitive function, adjusting for age, sex, accelerometer wear time, education, occupational status/PA, and smoking status., Results: In each cohort, achieving just 10-21.4 min/day moderate-to-vigorous PA related to better executive function ( P  < .02); and just 10 min/day moderate-to-vigorous PA was associated with better verbal memory in middle-aged adults in the Third Generation cohort ( P  = .02). In older adults of the Offspring cohort, total PA (measured in steps/day) was associated with better executive function ( P  < .02)., Discussion: PA at levels lower than the current PA Guidelines (just 10 min/day moderate-to-vigorous PA and total PA including lower intensity PA) were associated with better cognitive function., (© 2019 The Authors. Published by Elsevier Inc. on behalf of the Alzheimer's Association.)

Life stresses (LS) could affect levels of physical activity (PA) during adolescence, however research is limited. As different types of PA may have different determinants, the effects of LS on participation in moderate-to-vigorous PA (MVPA) and on organized and unorganized PA (OPA, UPA) were examined in a sample of 937 students (10-11 years-old) followed up over five years. Questionnaires were administered three times per year as part of the Monitoring Activities for Teenagers to Comprehend their Habits (MATCH) study. A total of 16 survey cycles were available for this analysis. At each survey cycle, participants reported exposure to nineteen LS, number of days per week attaining at least 60 min of MVPA, and participation in OPA and in UPA. LS were classified as personal or extrinsic life events, or personal or extrinsic life circumstances. Relationships among the four LS categories and PA outcomes were assessed using gender stratified mixed effects models. Personal circumstances attenuated the increase in MVPA in late childhood, and accentuated the decrease in MVPA in early adolescence (p < 0.001). In contrast, experiencing more extrinsic events attenuated the decrease in the number of reported UPA (p < 0.05). Among girls, experiencing more personal events attenuated the decrease in the number of UPA and OPA by 4.8% and 5.1% respectively. Among boys, experiencing more extrinsic circumstances attenuated the decrease in the number of UPA by 3.4%. The effect of LS on PA differed by gender and by type of PA, highlighting the need for careful tailoring of interventions., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In this article, the author discusses the results of the study regarding the required measures for pedometer-determined physical activity in youth. He remarks that the study considered the disparity among countries for the average daily steps the youth take, which should be regarded as a secondary outcome. He mentions that the estimates for the median steps/day did not describe differences in information. He adds that the estimates for the expected-curve challenged the common sense.