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Purpose: To assess the association between the amount of recess provision and children's accelerometer-measured physical activity (PA) levels. Methods: Parents/guardians of 6- to 11-year-olds (n = 451) in the 2012 National Youth Fitness Survey reported recess provision, categorized as low (10–15 min; 31.9%), medium (16–30 min; 48.0%), or high (>30 min; 20.1%). Children wore a wrist-worn accelerometer for 7 days to estimate time spent sedentary, in light PA, and in moderate to vigorous PA using 2 different cut points for either activity counts or raw acceleration. Outcomes were compared between levels of recess provision while adjusting for covariates and the survey's multistage, probability sampling design. Results: Children with high recess provision spent less time sedentary, irrespective of type of day (week vs weekend) and engaged in more light or moderate to vigorous PA on weekdays than those with low recess provision. The magnitude and statistical significance of effects differed based on the cut points used to classify PA (eg, 4.7 vs 11.9 additional min·d−1 of moderate to vigorous PA). Conclusions: Providing children with >30 minutes of daily recess, which exceeds current recommendations of ≥20 minutes, is associated with more favorable PA levels and not just on school days. Identifying the optimal method for analyzing wrist-worn accelerometer data could clarify the magnitude of this effect. [ABSTRACT FROM AUTHOR]

Background: Opt2Move is a theory-guided moderate and vigorous physical activity (MVPA) promotion trial that uses multiphase optimization strategy (MOST) methodology to evaluate the individual and combined effects of four intervention components in a full factorial experiment among young adult cancer survivors (YACS; N = 304). All participants will receive the core mHealth MVPA intervention, which includes a Fitbit and standard self-monitoring Opt2Move smartphone application. YACS will be randomized to one of 16 conditions to receive between zero and four additional components each with two levels (yes v. no): E-Coach, buddy, general mindfulness, and MVPA-specific mindfulness. Objective: The primary aim is to determine the individual and combined effects of the components on MVPA post-intervention (12-weeks) and at 24-week follow-up. The secondary aim is to examine how changes in MVPA are associated with patient-reported outcomes, light-intensity activity, sedentary time, and sleep duration and quality. Potential mediators and moderators of component effects will also be examined. Results: Results will support the selection of a package of intervention components optimized to maximize MVPA to be tested in a randomized controlled trial. Conclusion: Opt2Move represents the first systematic effort to use MOST to design an optimized, scalable mHealth MVPA intervention for YACS and will lead to an improved understanding of how to effectively change YACS' MVPA and ultimately, improve health and disease outcomes. [ABSTRACT FROM AUTHOR]

Indoor spaces are essential to most humans' lives. Furthermore, in many cases, buildings are shared indoor environments that contain diverse people and resources. Spatial patterns of use are important but under‐examined aspects of human‐building interactions. This study leverages perspectives from human‐environment geography and mechanical engineering to examine spatial patterns of use within a network of shared indoor spaces in an academic building at a research university in the United States. Here we ask: (1) What spaces and resources do building users value? and (2) How are values associated with observed measures of use? We hypothesise that spatial patterns of use follow an ideal free distribution (IFD), a common ecological model of resource use. To test this, we define measures of value and use derived from mixed qualitative (n = 50) and survey‐based social data (n = 196) and data from a building‐based system of accelerometers. Our analyses provide some support for the IFD hypothesis. We discuss the implications of this finding and potential new avenues for geographic research in shared indoor environments. [ABSTRACT FROM AUTHOR]

Introduction: Physical activity (PA) has shown great benefits in patients with chronic obstructive pulmonary disease (COPD); however, their PA is below average. Motivational factors associated with PA in COPD have not been widely studied and could be a target for improving adherence to PA. The objective of our study was to identify and understand the different motivational and confidence factors related to low levels of PA in a COPD cohort. Method: Observational, prospective, multicenter study of COPD patients. Sociodemographic data, respiratory symptoms, comorbidities, spirometry, and exercise capacity were collected. PA was measured using the Dynaport accelerometer and patient motivation and confidence in PA were assessed by a questionnaire previously used in a COPD population in the USA. Results: Eighty six COPD patients were included, 68.6% being male, with a mean (SD) age of 66.6 (8.5) years and a mean forced expiratory volume in the first second (%) of 50.9% (17.3%). The mean walking time was 82.8 (37.8) minutes/day. Questions related to health benefits and enjoying exercise were ranked highest in the motivation questionnaire and statistically significant differences were found in PA measures between patients with low and high motivation. A lack of confidence regarding hot weather and health-related issues significantly influenced PA levels. Advice from third parties, including healthcare providers, was not associated with higher PA levels. Conclusions: Improving the health of COPD patients is their main motivation to perform PA. Lack of confidence when it is hot or when they fear for their health is related to low levels of PA. Advice from third parties, including healthcare professionals, is not associated with higher PA. These results are relevant for developing strategies to increase the adherence of COPD patients to PA programs. [ABSTRACT FROM AUTHOR]

Background: Chinese American immigrants have been underrepresented in health research partly due to challenges in recruitment. Objectives: This study aims to describe recruitment and retention strategies and report adherence in a 7-day observational physical activity study of Chinese American immigrants with prior gestational diabetes during the COVID-19 pandemic. Methods: Foreign-born Chinese women aged 18--45 years, with a gestational diabetes index pregnancy of 0.5--5 years, who were not pregnant and had no current diabetes diagnosis were recruited. They wore an accelerometer for 7 consecutive days and completed an online survey. Multiple recruitment strategies were used: (a) culturally and linguistically tailored flyers, (b) social media platforms (e.g., WeChat [a popular Chinese platform] and Facebook), (c) near-peer recruitment and snowball sampling, and (d) a study website. Retention strategies included flexible scheduling and accommodation, rapid communications, and incentives. Adherence strategies included a paper diary and/or automated daily text reminders with a daily log for device wearing, daily email reminders for the online survey, close monitoring, and timely problem-solving. Results: Participants were recruited from 17 states; 108 were enrolled from August 2020 to August 2021. There were 2,479 visits to the study webpage, 194 screening entries, and 149 inquiries about the study. Their mean age was 34.3 years, and the mean length of U.S. stay was 9.2 years. Despite community outreach, participants weremainly recruited fromsocialmedia (e.g., WeChat). The majority were recruited via near-peer recruitment and snowball sampling. The retention rate was 96.3%; about 99% had valid actigraphy data, and 81.7% wore the device for 7 days. The majority of devices were successfully returned, and the majority completed the online survey on time. Discussion: We demonstrated the feasibility of recruiting and retaining a geographically diverse sample of Chinese American immigrants with prior gestational diabetes during the COVID-19 pandemic. Recruiting Chinese immigrants via social media (e.g., WeChat) is a viable approach. Nonetheless, more inclusive recruitment strategies are needed to ensure broad representation from diverse socioeconomic groups of immigrants. [ABSTRACT FROM AUTHOR]

Objectives: To explore the relationship between sleep duration and cognitive functions in older adults using NHANES, a national US population study dataset, and to explore the causal association with Mendelian randomization (MR) using the UK Biobank. Methods: First, an observational study was conducted with the NHANES database with participants ≥60 years. Sleep duration was measured with accelerometers for 7 consecutive days. Participants were divided into habitual short sleep (<7 h) and long sleep (>9 h) groups. Cognitive functions were measured with the CERAD Word Learning sub-set, Animal Fluency, and Digit Symbol Substitution test (DSST). Multivariate regression models were used to explore relationships between sleep duration and cognitive functions. Second, bidirectional MR was conducted with data for self-reported sleep duration, which came from a genome-wide association study (GWAS) comprising 446,118 adults from the UK Biobank, and general cognitive performance, which was obtained from a recent GWAS study (N = 257,841). Inverse-variance weighted (IVW) was used as the primary estimation of the outcome. Results: In the observational study, 2687 participants were included. Sleep duration was associated with cognitive functions in a non-linear way. Habitual long sleep (>9°h) was associated with lower scores on DSST (OR = 0.01, p =.003) in the fully-adjusted model. The association between habitual short sleep and cognitive functions was insignificant. For the MR, genetically predicted lower general cognitive performance was causally associated with a higher prevalence of habitual short sleep (OR = 0.97, p = 5.1 × 10−7) and long sleep (OR = 0.97, p = 8.87 × 10−16). Discussion: Short and long sleep duration might be both causally associated with worse outcomes of cognitive functions in older adults, highlighting the importance of maintaining sleep health. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the association between physical activity, sedentary behaviour and chronic inflammation in short sleep adults. The study included 2,113 NHANES participants with self-reported insufficient sleep. C-reactive protein (CRP) was used as the inflammatory biomarker. Physical activity and sedentary behaviour were objectively measured by accelerometers. Weighted regression model, two – piecewise linear regression model, and restricted cubic splines were applied to evaluate associations mentioned above. An isotemporal substitution model was used to assess the modelled effects of replacing sedentary time (ST) with moderate-to-vigorous levels of physical activity (MVPA) or light physical activity (LPA). After adjusting for potential confounding factors, higher levels of ST and lower levels of LPA or MVPA were associated with higher CRP levels. Isotemporal substitution analysis indicated that replacing 30 minutes of ST with 30 minutes of MVPA was associated with a significant decrease in CRP levels. Saturation analysis suggested that the association between MVPA and CRP may plateau at over 20 minutes of MVPA per day. Findings of this study provides insight into the potential benefits of replacing ST with MVPA. This study also suggests that increasing MVPA beyond a certain point may not provide additional anti-inflammatory benefits in a short sleep population. [ABSTRACT FROM AUTHOR]

Purpose: Accelerometers are used to objectively measure physical behaviors in free-living environments, typically for seven consecutive days or more. We examined whether participants experience "wear fatigue," a decline in wear time day over day, during typical assessment period acquired in a nationally representative sample of 6- to 80-yr-olds in the United States. Methods: Participants were instructed to wear an ActiGraph GT3X+ on their nondominant wrist continuously for seven consecutive days. Participants with seven complete days of recorded data, regardless of wear status, were included in the analyses (N = 13,649). Wear was scored with the sleep, wake, and nonwear algorithm. Results: Participants averaged 1248 ± 3.6 min·d−1 (mean ± SE) of wear over the assessment, but wear time linearly decreased from day 1 (1295 ± 3.2 min) to day 7 (1170 ± 5.3 min), resulting in a wear fatigue of −18.1 ± 0.7 min·d−1 (β ± SE). Wear fatigue did not differ by sex but varied by age-group—highest in adolescents (−26.8 ± 2.4 min·d−1) and lowest in older adults (−9.3 ± 0.9 min·d−1). Wear was lower in evening (1800–2359 h) and early morning (0000–0559 h) compared with the middle of the day and on weekend days compared with weekdays. We verified similar wear fatigue (−23.5 ± 0.7 min·d−1) in a separate sample (N = 14,631) with hip-worn devices and different wear scoring. Applying minimum wear criteria of ≥10 h·d−1 for ≥4 d reduced wear fatigue to −5.3 and −18.7 min·d−1 for the wrist and hip, respectively. Conclusions: Patterns of wear suggest noncompliance may disproportionately affect estimates of sleep and sedentary behavior, particularly for adolescents. Further study is needed to determine the effect of wear fatigue on longer assessments. [ABSTRACT FROM AUTHOR]

Background: Suboptimal rest-activity patterns in adolescence are associated with worse health outcomes in adulthood. Understanding sociodemographic factors associated with rest-activity rhythms may help identify subgroups who may benefit from interventions. This study aimed to investigate the association of rest-activity rhythm with demographic and socioeconomic characteristics in adolescents. Methods: Using cross-sectional data from the nationally representative National Health and Nutrition Examination Survey (NHANES) 2011–2014 adolescents (N = 1814), this study derived rest-activity profiles from 7-day 24-hour accelerometer data using functional principal component analysis. Multiple linear regression was used to assess the association between participant characteristics and rest-activity profiles. Weekday and weekend specific analyses were performed in addition to the overall analysis. Results: Four rest-activity rhythm profiles were identified, which explained a total of 82.7% of variance in the study sample, including (1) High amplitude profile; (2) Early activity window profile; (3) Early activity peak profile; and (4) Prolonged activity/reduced rest window profile. The rest-activity profiles were associated with subgroups of age, sex, race/ethnicity, and household income. On average, older age was associated with a lower value for the high amplitude and early activity window profiles, but a higher value for the early activity peak and prolonged activity/reduced rest window profiles. Compared to boys, girls had a higher value for the prolonged activity/reduced rest window profiles. When compared to Non-Hispanic White adolescents, Asian showed a lower value for the high amplitude profile, Mexican American group showed a higher value for the early activity window profile, and the Non-Hispanic Black group showed a higher value for the prolonged activity/reduced rest window profiles. Adolescents reported the lowest household income had the lowest average value for the early activity window profile. Conclusions: This study characterized main rest-activity profiles among the US adolescents, and demonstrated that demographic and socioeconomic status factors may shape rest-activity behaviors in this population. [ABSTRACT FROM AUTHOR]

Understanding the relationship between head mass and neck stiffness during direct head impacts is especially concerning in youth sports where athletes have higher proportional head mass to neck strength. This study compared 2 neck stiffness conditions for peak linear and rotational acceleration and brain tissue deformations across 3 impact velocities, 3 impact locations, and 2 striking masses. A pendulum fitted with a nylon cap was used to impact a fifth percentile hybrid III headform equipped with 9 accelerometers and fitted with a youth American football helmet. The 2 neck stiffness conditions consisted of a neckform with and without resistance in 3 planes, representing the upper trapezius, the splenius capitis, and the sternocleidomastoid muscles. Increased neck stiffness resulted in significant changes in head kinematics and maximum principal strain specific to impact velocity, impact location, and striking mass. [ABSTRACT FROM AUTHOR]

Purpose: In a cross-sectional sample of US Hispanic/Latino adults, we aimed to describe step-based metric distributions, estimate their associations with activity counts and self-report, and calibrate step-based translations of current (2018) US physical activity (PA) guidelines, that is, ≥150 min·wk-1 moderate-to-vigorous PA (MVPA) from accelerometer counts and self-report. Methods: The Hispanic Community Health Study/Study of Latinos enrolled 16,415 Hispanic/Latino adults 18-74 yr from four US cities (2008-2011). Participants completed the Global PA Questionnaire and 1 wk of Actical accelerometer wear (n = 12,528). Weighted medians were used to describe step-based metrics, and Spearman correlations estimated their relationships with count-based and self-reported PA indicators. Receiver operator characteristic curve analyses were used to examine the ability of each step-basedmetric to classify participantsmeeting PAguidelines. Results: Overall, US Hispanic/Latino adults accumulated medians of 6770 steps per day and 6, 18, 236, and 630 min·d-1 at ≥100, ≥70, 1-69, and 0 steps perminute, respectively. Count-based time inMVPA, light PA, and sedentary behavior weremost strongly correlated (rs = 0.79-0.85) with times ≥70, 1-69, and 0 steps perminute, respectively,whereas self-reported MVPA had similar correlations with steps per day and times ≥40 and ≥70 steps per minute (rs = 0.28-0.29). Time ≥70 steps per minute had the greatest capacity to classify participants meeting PA guidelines with both measures of MVPA. Conclusions: This study provides the first normative values (based on percentiles) of step-based metrics for US Hispanic/Latino adults, which can facilitate surveillance, program planning, research, and data interpretation. Our finding that PA guidelines corresponded to 6000-7000 steps per day or ~20 min·d-1 at ≥70 steps per minute with an Actical accelerometer can be considered alongside dose-response relationships with health outcomes to develop step-based recommendations that are consistent with and better communicate PA guidelines. [ABSTRACT FROM AUTHOR]

Aim: The objective of the current study was to examine whether physical activity and sedentary behavior were associated with appetite among community‐dwelling older adults. Methods: Cross‐sectional analysis was performed on three cohort studies: the Longitudinal Aging Study Amsterdam (LASA); the Health, Aging and Body Composition Study (HABC Study) and the I'm Still Standing Study (ISS Study); (n = 1173, n = 162, n = 125; age range: 57–99, 85–95, 80–100 years; women: 51%, 56%, 61%, respectively). Physical activity and sedentary behavior were measured using hip‐worn (LASA and HABC) and wrist‐worn (ISS) accelerometers. Appetite was self‐reported. Logistic regression models were fitted by accelerometer placement to explore the association between good appetite and various physical activity metrics (total activity, sedentary behavior, and time spent in different intensities of physical activity). Results: Among cohorts using hip‐worn accelerometers, those having total activity within the highest tertile had more than double the odds of having good appetite compared with those within the lowest tertile (odds ratio [OR] 2.16 (1.15–4.06)). Each additional percent of daily sedentary behavior decreased the odds for having good appetite by 3% (OR 0.97 (0.95–0.996)), while each additional percent of daily light‐intensity physical activity increased the odds for having good appetite by 4% (OR 1.02 (1.01–1.06)). No association was found between either physical activity or sedentary behavior and appetite for measurements with the wrist‐worn accelerometers. Conclusions: Among community‐dwelling older adults, the associations between appetite, accelerometer‐assessed physical activity and sedentary behavior differ by accelerometer placement location. This study highlights the importance of careful interpretation of accelerometer data from different body locations and concurrent health outcomes. Geriatr Gerontol Int 2023; 23: 411–417. [ABSTRACT FROM AUTHOR]

Introduction: Physical activity is important for children's health and well-being. Supportiveness for physical activity of home and neighborhood environments may affect children's PA, but most studies are cross-sectional. We examined environmental predictors of change in children's physical activity over two years. Methods: Data were from the longitudinal, observational cohort study, 'Neighborhood Impact on Kids'. Participants were children (initially aged 6–12 years) and their parent/caregiver (n = 727 dyads) living in neighborhoods throughout San Diego County, California and King County (Seattle area), Washington, USA. Children's moderate-to-vigorous physical activity (MVPA) was measured using accelerometers at T1 (Time 1 or baseline, 2007–2009) and T2, the two-year follow-up. At T1, parents survey-reported on physical activity (PA) equipment at home and demographics. Neighborhood environment was measured using spatial data in Geographic Information Systems (intersection density; park availability) and in-person audits (informal play space near home; park-based PA facilities; land use; support for walking/cycling). Generalized additive mixed models estimated total effects, then direct effects, of environmental attributes on MVPA at T1. Two-way moderating effects of child's sex and age were examined at T1. To examine associations of environmental exposures with changes in MVPA, we estimated interaction effects of environmental attributes on the association between time and MVPA. Results: On average, children accumulated 146 min/day (standard deviation or SD = 53) of MVPA at T1, and 113 (SD = 58) min/day at T2. There were no significant total or direct effects of environmental attributes on MVPA at T1, and no significant two-way interaction effects of child's age and sex for T1 MVPA. Having informal play spaces proximal to home with more amenities was associated with less MVPA decline from T1 to T2. Higher residential density, higher land use mix, and higher number of PA facilities in nearby parks were unexpectedly associated with greater MVPA decline. Conclusion: Higher quality informal play spaces close to home may help offset declines in MVPA during middle childhood, as they may promote unstructured active play with opportunities for parental or neighbor surveillance. Unexpectedly, environmental factors consistent with higher walkability were associated with greater declines in children's MVPA. As physical activity differs across the lifespan, so may environmental factors that facilitate it. [ABSTRACT FROM AUTHOR]

Physical inactivity has increasingly affected public health in the United States during the COVID‐19 pandemic as it is associated with chronic diseases such as arthritis, cancer, and heart disease. Contingency management has been shown to increase physical activity. Therefore, the present study sought to evaluate the effects of an escalating schedule of monetary reinforcement with a reset contingency on physical activity, as compared between 2 counterbalanced groups in which a monetary deposit of $25 was either required (deposit group) or not (no‐deposit group). Twenty‐five adults wore Fitbit accelerometers to monitor step counts. An ABA reversal design was used; in the 2 baseline phases, no programmed contingencies were in place for step counts. During intervention, step goals were set using a modified 70th percentile schedule with a 7‐day window: Reaching the first goal would result in $0.25, and incentives increased by $0.25 for each subsequent day in which the goal was met. Failure to reach a goal resulted in a reset of the monetary incentive value to $0.25. Ten out of 12 participants from the deposit group were determined to be responders to intervention, whereas 8 out of 13 participants from the no‐deposit group were determined to be responders to intervention. Overall, there were no significant differences between the groups' step counts. However, the deposit group's intervention was cheaper to implement, which suggests that deposit contracts are a viable modification for physical activity interventions. [ABSTRACT FROM AUTHOR]

Context: During thoroughbred races, jockeys are placed in potentially injurious situations, often with inadequate safety equipment. Jockeys frequently sustain head injuries; therefore, it is important that they wear appropriately certified helmets. Objective: The goals of this study are (1) to perform impact attenuation testing according to ASTM F1163-15 on a sample of equestrian helmets commonly used by jockeys in the United States and (2) to quantify headform acceleration and residual crush after repeat impacts at the same location. ParticipantsandDesign: Seven helmet models underwent impact attenuation testing according to ASTM F1163-15. A second sample of each helmet model underwent repeat impacts at the crown location for a total of 4 impacts. Setting: Laboratory. Intervention: Each helmet was impacted against a flat and equestrian hazard anvil. MainOutcome Measures: Headform acceleration was recorded during all impact and computed tomography scans were performed preimpact and after impacts 1 and 4 on the crown to quantify liner thickness. Results: Four helmets had 1 impact that exceeded the limit of 300g. During the repeated crown impacts, acceleration remained below 300g for the first and second impacts for all helmets, while only one helmet remained below 300g for all impacts. Foam liner thickness was reduced between 5% and 39% after the first crown impact and between 33% and 70% after the fourth crown impact. Conclusions: All riders should wear a certified helmet and replace it after sustaining a head impact. Following an impact, expanded polystyrene liners compress, and their ability to attenuate head acceleration during subsequent impacts to the same location is reduced. Replacing an impacted helmet may reduce a rider's head injury risk. [ABSTRACT FROM AUTHOR]

Youth with developmental disabilities (DD) face challenges that may impact their participation in physical activity. One of the biggest challenges is the availability of opportunities to engage in activities that are adapted for youth with DD. In addition, due to challenges with current physical activity assessment methods for youth with DD, the activity levels during modified activities remain unclear. The purpose of this investigation was to determine the activity levels of youth with DD during structured and unstructured activities offered during a therapeutic camp. This camp was a five-day, overnight experience in an outdoor camp center in the southeastern region of the U.S. Youth (n = 29; 14.6 ± 3.9 years) with more than one DD and with varying abilities wore accelerometers while they engaged in 13 activities of varying categories (functional/gross motor, game, sociodramatic, fine motor, free play) and contexts (ropes, horses, outdoor adventure, music and movement, yoga, come on down, sports and games, theatre, cabin challenge, arts, cooking, mad science, free play). Activity level varied by activity category and context and the intensity level of the majority of the camp activities was classified as either sedentary or light. There was a time course effect on activity; most activities resulted in a gradual decline over the session, except for cooking, sports and games, and free play. This therapeutic camp provided an opportunity for youth to engage in physical activity that would be classified as light intensity. The activities available at this camp were designed to address specific goals and objectives and provided enrichment opportunities (e.g., life skills, social skills) for youth to obtain multiple skills while using movement as a framework to deliver the content. [ABSTRACT FROM AUTHOR]

Purpose: Sedentary behavior is associated with poor physical function in older adults, which can lead to accelerated skeletal muscle aging (sarcopenia) and premature mortality. We examined the independent and joint effects of sedentary behavior and moderate to vigorous intensity physical activity (MVPA) with measures of physical functioning. Methods: We studied 5408 participants in the REasons for Geographic and Racial Differences in Stroke study who wore a hip-mounted accelerometer over seven consecutive days (2009–2013) and had self-reported and directly observed physical function (time walk, chair stand test) measured during an in-home visit conducted from 2013 to 2016. Results: Greater sedentary time was significantly associated with poorer chair stand and timed walk scores. Substituting 30 min of sedentary time with 30 min of MVPA was associated with significant improvements in chair stands (β −0.57; P = 0.007) and timed walk (β −0.36; P = 0.01). Similar, but less robust, findings were observed for reallocations of sedentary time to light-intensity physical activity. In joint association analyses, high sedentary time in combination with low MVPA (but not in combination with high MVPA) was associated with poorer physical function compared with the referent group (low sedentary time/high MVPA; P < 0.001 for all). Conclusions: Greater time spent being sedentary was associated with worse physical functioning outcomes. However, reallocations of sedentary time to light-intensity physical activity, and especially MVPA, were associated with more favorable physical functioning. Interventions aimed to increase MVPA and reduce sedentary behavior should be a priority, especially among populations at greatest risk for sarcopenia and physical function decline. [ABSTRACT FROM AUTHOR]

Early childhood is an important development period for establishing healthy physical activity (PA) habits. The objective of this study was to evaluate PA levels in a representative sample of U.S. preschool-aged children. The study sample included 301 participants (149 girls, 3–5 years of age) in the 2012 U.S. National Health and Examination Survey National Youth Fitness Survey. Participants were asked to wear an ActiGraph accelerometer on their wrist for 7 days. A machine learning random forest classification algorithm was applied to accelerometer data to estimate daily time spent in moderate- and vigorous-intensity PA (MVPA; the sum of minutes spent in running, walking, and other moderate- and vigorous-intensity PA) and total PA (the sum of MVPA and light-intensity PA). We estimated that U.S. preschool-aged children engaged in 28 min/day of MVPA and 361 min/day of total PA, on average. MVPA and total PA levels were not significantly different between males and females. This study revealed that U.S. preschool-aged children engage in lower levels of MVPA and higher levels of total PA than the minimum recommended by the World Health Organization. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to examine the independent and combined association of physical activity and body mass index (BMI) with blood pressure in youth. Methods: Youth aged 8-18 years from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) with BMI, blood pressure, and physical activity (accelerometer) were included in the analyses. A total of 2585 subjects (1303 males; 47% of all 8- to 18-year-olds) met these criteria. Results: Obese youth had a systolic blood pressure that was 8 mm Hg higher than normal weight youth. A significant interaction between BMI and physical activity on blood pressure was found (P < .001), and group differences among the BMI/activity groups showed that the 3 obese groups and the overweight/least active group had significantly higher systolic blood pressure than the normal weight/active group across all analyses. The overweight/least active and normal weight/least active groups had significantly higher diastolic blood pressure than the normal weight/active group as well. Conclusions: This study showed a significant independent and combined association of BMI and physical activity with blood pressure in youth. Interventions need to focus on the reduction of fatness/BMI as a way to reduce the cardiovascular risk in youth. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to assess the association of a wrist-worn, device-based metric of 24-h movement with cognitive function and subjective cognitive complaints among older adults, 60 yr and older. Methods: This is a cross-sectional analysis of the 2011–2012 and 2013–2014 National Health and Nutrition Examination Survey (NHANES) cycles. A wrist-worn ActiGraph GT3X+ accelerometer captured total 24-h movement activity, analyzed as Monitor-Independent Movement Summary units (MIMS-units), and quantified into placement based on an age- and sex-standardized percentile. Cognitive tests in the domains of memory, language/verbal fluency, and executive performance were administered. Test-specific cognitive z -scores were generated. Subjective cognitive complaints included perceived difficulty remembering and confusion/memory loss. Results: The analytical sample included 2708 U.S. older adults (69.5 ± 0.2 yr, 55% female, 20.9% non-White). Multivariable linear regressions revealed those in quartiles 3 (50th–74th percentile) and 4 (≥75th percentile) for their age and sex had higher cognitive function z -scores across all domains compared with those in quartile 1. Logistic regressions demonstrated those in quartiles 3 and 4 also had lower odds of reporting difficulty remembering (adjusted odds ratio [AOR] = 0.52, 95% confidence interval [CI] = 0.31–0.89; AOR = 0.57, 95% CI = 0.37–0.88) and confusion/memory loss (AOR = 0.49, 95% CI = 0.27–0.91; AOR = 0.49, 95% CI = 0.27–0.98), respectively, compared with those in quartile 1. Conclusions: In a representative sample of U.S. older adults, higher cognitive functioning occurs among those that perform total 24-h movement activity at or above the 50th percentile for their age and sex. Future studies should consider movement behaviors across a 24-h period on cognitive health outcomes in older adults. More research exploring prospective associations of MIMS-units and time-use behaviors across midlife and older adulthood that may affect cognitive functioning across diverse populations is needed. [ABSTRACT FROM AUTHOR]

The current physical activity (PA) guidelines for children and adolescents in the United States recommend >=60 min of moderate- to vigorous-intensity PA (MVPA), 7 d[middle dot]wk-1 for cardiometabolic health (CmH) benefits. Although the duration and intensity components of the PA guidelines have been rigorously studied, the frequency (7 d[middle dot]wk-1) component has not been thoroughly researched. Purpose: This study aimed to examine the association of the frequency component of the weekly PA guidelines on CmH in youth. Methods : Cross-sectional accelerometer data from the 2003-2006 National Health and Nutrition Examination Survey included youth age 6-18 yr with >=4 d, >=10 h of wear time, and averaging >=60 min[middle dot]d-1 of MVPA (n = 656). Participants were categorized into quartiles based on the proportion of days where they met the guidelines (>=60 min of MVPA). CmH variables were categorized as weight status/body anthropometrics, blood pressure, cholesterol, and fasting serum laboratory results. Propensity score weighting was applied to quartiles, and general linear modeling was used to compare associations of quartiles with CmH variables. Results : Results are displayed as percent of days meeting guidelines (DMG; 95% confidence interval): MVPA in minutes per week: Q1 (n = 156; DMG = 45.8% (43.4%-48.1%); MVPA 467.5, min[middle dot]wk-1), Q2 (n = 165; DMG = 62.6% (61.6%-63.7%); MVPA, 474.4 min[middle dot]wk-1), Q3 (n = 148; DMG = 75% (74.1%-75.8%); MVPA, 446.5 min[middle dot]wk-1), Q4 (n = 187; DMG = 92.2% (87.7%-96.6%); MVPA, 453.2 min[middle dot]wk-1). After adjusting for confounders and multiple comparisons, there were no clinically significant differences in weight status/body anthropometrics, blood pressure, cholesterol, or fasting serum laboratory results between DMG quartiles. Conclusions : We found no association between the proportion of DMG and CmH in children and adolescents. Our study suggests that achieving an overall weekly average of 60 min[middle dot]d-1 of MVPA seems to be sufficient for CmH regardless of the 7 d[middle dot]wk-1 frequency requirement of the PA guideline. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine the shape of the relationship between physical activity (PA) and total energy expenditure (TEE) and to explore the role of energy balance status (negative, stable, positive) in influencing this association. Methods : Cross-sectional. Participants were 584 older adults (50-74 yr) participating in the Interactive Diet and Activity Tracking in AARP study. TEE was assessed by doubly labeled water and PA by accelerometer. The relationship between PA and TEE was assessed visually and using nonlinear methods (restricted cubic splines). Percent weight change (>3%) over a 6-month period was used as a proxy measurement of energy balance status. Results : TEE generally increased with increasing deciles of PA averaging 2354 (SD, 351) kcal[middle dot]d-1 in the bottom decile to 2693 (SD, 480) kcal[middle dot]d-1 in the top decile. Cubic spline models showed an approximate linear association between PA and TEE (linear relation, P < 0.0001; curvature, P = 0.920). Results were similar in subgroup analyses for individuals classified as stable or positive energy balance. For those in negative energy balance, TEE was generally flat with increasing deciles of PA averaging 2428 (SD, 285) kcal[middle dot]d-1 in the bottom decile to 2372 (SD, 560) kcal[middle dot]d-1 in the top decile. Conclusions: Energy balance status seems to play an important role in the relationship between PA and TEE. When in a positive energy balance, the relationship between TEE and PA was consistent with an additive model; however, when energy balance was negative, TEE seems to be consistent with a constrained model. These findings support PA for weight gain prevention by increasing TEE; however, the effect of PA on TEE during periods of weight loss may be limited. An adequately powered, prospective study is warranted to confirm these exploratory findings. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to present age- and sex-specific percentiles for daily wrist-worn movement metrics in US youth and adults. This metric represents a summary of all recorded movement, regardless of the purpose, context, or intensity. Methods: Wrist-worn accelerometer data from the combined 2011--2014 National Health and Nutrition Examination Survey cycles and the 2012 National Health and Nutrition Examination Survey National Youth Fitness Survey were used for this analysis. Monitor-Independent Movement Summary units (MIMS-units) from raw triaxial accelerometer data were used. We removed the partial first and last assessment days and days with ≥5% nonwear time. Participants with ≥1 valid day were included. Mean MIMS-units were calculated across all valid days. Percentile tables and smoothed curves of daily MIMS-units were calculated for each age and sex using the Generalized Additive Models for Location Shape and Scale. Results: The analytical sample included 14,705 participants age ≥3 yr. The MIMS-unit activity among youth was similar for both sexes, whereas adult females generally had higher MIMS-unit activity than did males. Median daily MIMS-units peaked at age 6 yr for both sexes (males, 20,613; females, 20,706). Lowest activity was observed for males and females 80+ yr of age: 8799 and 9503, respectively. Conclusions: Population referenced MIMS-unit percentiles for US youth and adults are a novel means of characterizing total activity volume. By using MIMS-units, we provide a standardized reference that can be applied across various wrist-worn accelerometer devices. Further work is needed to link these metrics to activity intensity categories and health outcomes. [ABSTRACT FROM AUTHOR]

Background: Schools are in a unique position to ensure that all students meet the current physical activity (PA) recommendations. This study aimed to examine 1st to 3rd grade elementary students' accelerometer measured school day PA in the United States (U.S.) and Finland. Methods: The sample consisted of 200 students (107 girls, 93 boys; ages 6 to 8) and their school day PA was monitored with hip-worn ActiGraph GT3X+ accelerometers across a 5-day school week and the thresholds 100 and 2296 count per minute were used to separate sedentary time, light PA, and moderate-to-vigorous PA (MVPA). Results: On an average school day, students were engaged in MVPA for 20.0 min in the U.S. and 24.1 min in Finland. Students' school-day MVPA was 9 to 16 minutes higher during physical education (PE) days compared with non-PE days (U.S: 25.8 vs. 16.6 min/day; Finland: 36.3 vs. 20.1 min/day). Girls had less MVPA and more sedentary time compared with boys in both samples. Conclusion: This study highlights both the role of PE and other school day physical activities in meeting PA guidelines. Policy measures are needed to change the structure of the school day and enhance PA to ensure that students meet the PA recommendations. [ABSTRACT FROM AUTHOR]

This study describes moderate to vigorous physical activity (MVPA) and sedentary behavior among New York City (NYC) residents 60 years and older and compared with national United States' estimates. Adults aged 60 or older living in NYC (n = 760) were compared with similar aged adults from the National Health and Nutrition Examination Survey (NHANES; n = 2,451 adults). Both groups wore an ActiGraph accelerometer for one week. The NYC sample recorded 13.2, 23.8, and 37.8 mean min/day of MVPA and the NHANES sample recorded 10.6, 21.1, and 39.3, depending on the definition. Sedentary behavior averaged 9.6 hr/day for the NYC sample and 9.3 hr/day for the NHANES sample. The NYC sample spent a longer proportion of time in sedentary behavior and light activities, but more time in MVPA than the NHANES sample. Urbanicity may explain some of the differences between the two samples. [ABSTRACT FROM AUTHOR]

Background: Daily time spent in sleep, sedentary behaviour (SED), light intensity physical activity (LIPA), and moderate-to-vigorous intensity physical activity (MVPA) are compositional, co-dependent variables. The objectives of this study were to use compositional data analysis to: (1) examine the relationship between the movement behaviour composition (daily time spent in sleep, SED, LIPA and MVPA) and all-cause mortality risk, and (2) estimate the extent to which changing time spent in any given movement behaviour (sleep, SED, LIPA, or MVPA) within the movement behaviour composition was associated with changes in risk of all-cause mortality. Methods: 2838 adult participants from the 2005–2006 cycle of the U.S. National Health and Nutrition Examination Survey were studied using a prospective cohort design. Daily time spent in SED, LIPA and MVPA were determined by accelerometer. Nightly time spent sleeping was self-reported. Survey data were linked with mortality data through to the end of December 2015. Compositional data analysis was used to investigate relationships between the movement behaviour composition and mortality. Results: The movement behaviour composition was significantly associated with mortality risk. Time spent in MVPA relative to other movement behaviours was negatively associated with mortality risk (HR =.74; 95% CI [.67,.83]) while relative time spent in SED was positively associated with mortality risk (HR = 1.75; 95% CI [1.10, 2.79]). Time displacement estimates revealed that the greatest estimated changes in mortality risk occurred when time spent in MVPA was decreased and replaced with sleep, SED, LIPA or a combination of these behaviours (HRs of 1.76 to 1.80 for 15 min/day displacements). Conclusions: The daily movement behaviour composition was related to mortality. Replacing time in MVPA or SED with equivalent time from any other movement behaviour was associated with an increase and decrease in mortality risk, respectively. [ABSTRACT FROM AUTHOR]

In the article, the author presents their study on the normative reference values for actigraphy-measured total nocturnal sleep time in U.S. children and adults using data from the National Health and Nutrition Examination Survey (NHANES). The results showed that total nocturnal sleep is similar among males and females.

OBJECTIVES Physical activity is associated with improved pain, functional status, and less disability in persons with knee osteoarthritis (KOA). Because polypharmacy is related to several adverse health outcomes in older persons, we hypothesized that it might also be associated with decreased physical activity in those with KOA. This study evaluates the relationship between the number of prescription medications and weekly moderate to vigorous physical activity (MVPA). DESIGN We used hierarchical median quantile regression analysis to examine the cross‐sectional association between the number of prescription medications taken in the past 30 days and the median objectively measured MVPA minutes controlling for demographic and clinical variables. SETTING Four Osteoarthritis Initiative (OAI) recruitment centers in Providence, Rhode Island; Columbus, Ohio; Baltimore, Maryland; and Pittsburgh, Pennsylvania. PARTICIPANTS Accelerometer monitoring occurred in 2,127 OAI participants. Of these, 1,889 participants had 4 or more days of valid physical activity monitoring data and complete medication/covariate data. Data were collected at the 48‐month OAI follow‐up visit (2008‐2010). MEASUREMENTS The outcome was weekly minutes of MVPA measured with an accelerometer. Number/type of prescribed medications and covariate data (age, sex, race/ethnicity, body mass index, presence of comorbidities, pain, depressive symptoms, and radiographic KOA severity) were taken from the public OAI database. Polypharmacy was defined as taking five or more prescribed medications. RESULTS: The prevalence of polypharmacy in the study population was 28.2%. Each additional prescription medication was related to a decrease of 3.6 minutes (95% confidence interval [CI] = −4.8 to −2.1) in median weekly MVPA minutes. Participants meeting the polypharmacy criterion exhibited a decrease of 12.6 minutes (95% CI = −21.2 to −4.7) in median weekly MVPA minutes compared with those not meeting the criterion. CONCLUSION: An increased number of prescription medications and polypharmacy are associated cross‐sectionally with decreased MVPA in adults with KOA. Further study is necessary to establish the causal nature of this association. [ABSTRACT FROM AUTHOR]

Objective: Static balance, postural stability, and reaction time are commonly impaired after a sport-related concussion. The Sway Balance System assesses postural sway (ie, stability) and simple reaction time using the triaxial accelerometer built into iOS mobile devices. The purpose of this study was to provide normative data for children and adolescents and to examine for age and sex differences on the Sway Balance System. Design: Cross-sectional study. Setting: Middle and high schools across the United States. Participants: Participants were 3763 youth aged 9 to 21 years who completed the Sway Balance System Sports protocol in accordance with the company's recommended methods (ie, 1 acclimation trial and 2-3 baseline tests). Independent variables: Age and sex. Main outcome measures: Sway Balance score (0-100) and Sway Reaction Time score (0-100). Statistical analysis: A multivariate analysis of variance examined the effects of age and sex on balance and reaction time scores. Results: Sway Balance and Reaction Time scores significantly differed by age [F(10, 7494) = 39.68, P < 0.001, V = 0.10, η²p = 0.05] and sex [F(4, 7494) = 55.29, P < 0.001, V = 0.06, η²p = 0.03]. Post hoc analyses revealed that older groups generally had better scores than younger groups on all balance comparisons (ps < 0.001) and many reaction time comparisons. Girls performed better than boys on balance [F(2, 3747) = 53.79, P < 0.001, η²p = 0.03] and boys had faster reaction times [F(2, 3747) = 37.11, P < 0.001, η²p = 0.02]. Conclusions: Age and sex are important factors to consider when assessing Balance and Reaction Time scores using the Sway Balance System's Sports protocol in youth. We provide age- and sex-based normative values for the Sway Balance System, which will likely be helpful when using this technology to assess and manage concussions. [ABSTRACT FROM AUTHOR]

Background: Sedentary behavior (SB) is linked to negative health outcomes in older adults. Most studies use summary values, e.g., total sedentary minutes/day. Diurnal timing of SB accumulation may further elucidate SB-health associations. Methods: Six thousand two hundred four US women (mean age = 79 ± 7; 50% White, 34% African-American) wore accelerometers for 7-days at baseline, yielding 41,356 person-days with > 600 min/day of data. Annual follow-up assessments of health, including physical functioning, were collected from participants for 6 years. A novel two-phase clustering procedure discriminated participants' diurnal SB patterns: phase I grouped day-level SB trajectories using longitudinal k-means; phase II determined diurnal SB patterns based on proportion of phase I trajectories using hierarchical clustering. Mixed models tested associations between SB patterns and longitudinal physical functioning, adjusted for covariates including total sedentary time. Effect modification by moderate-vigorous-physical activity (MVPA) was tested. Results: Four diurnal SB patterns were identified: p1 = high-SB-throughout-the-day; p2 = moderate-SB-with-lower-morning-SB; p3 = moderate-SB-with-higher-morning-SB; p4 = low-SB-throughout-the-day. High MVPA mitigated physical functioning decline and correlated with better baseline and 6-year trajectory of physical functioning across patterns. In low MVPA, p2 had worse 6-year physical functioning decline compared to p1 and p4. In high MVPA, p2 had similar 6-year physical functioning decline compared to p1, p3, and p4. Conclusions: In a large cohort of older women, diurnal SB patterns were associated with rates of physical functioning decline, independent of total sedentary time. In particular, we identified a specific diurnal SB subtype defined by less SB earlier and more SB later in the day, which had the steepest decline in physical functioning among participants with low baseline MVPA. Thus, diurnal timing of SB, complementary to total sedentary time and MVPA, may offer additional insights into associations between SB and physical health, and provide physicians with early warning of patients at high-risk of physical function decline. [ABSTRACT FROM AUTHOR]

Background: Observational studies linking physical activity with mortality are susceptible to reverse causation bias from undiagnosed and prevalent diseases. Researchers often attempt to deal with reverse causation bias by excluding deaths occurring within the first 1 or 2 years from the analysis, but it is unclear if excluding deaths within this time-frame is sufficient to remove bias. Methods: We examined associations between total and intensity-specific physical activity and sedentary time with all-cause mortality in a prospective cohort of 3542 individuals from the 2003–2006 NHANES cycles. In order to yield measures of association hypothesized as minimally influenced by reverse causation bias the primary analysis excluded individuals with < 5 years of follow-up. Accelerometer-measured physical activity was linked with recently updated vital status from the National Death Index with a median follow-up of 10.8 years. Results: Hazard ratios (95% confidence intervals) were 0.74 (0.53, 1.04), 0.52 (0.37, 0.73), and 0.61 (0.38, 1.01) for ascending quartiles of total physical activity against the least active reference. Hazard ratios for ascending moderate-to-vigorous physical activity quartiles against the reference were 0.67 (0.47, 1.96), 0.67 (0.47, 0.95), and 0.68 (0.39, 1.18). Associations for light intensity physical activity and sedentary time were smaller in magnitude and all confidence intervals included unity. Total activity and moderate-to-vigorous physical activity hazard ratios from analyses only excluding deaths within the first 2 years were inflated by 13 and 26% relative to analysis restricted to ≥5 years of follow-up. Conclusions: The pattern of associations suggested total physical activity and moderate-to-vigorous physical activity were associated with lower mortality after more than 10 years of follow-up and excluding the first 5 years of observation time to minimize the impact of reverse causation bias. Excluding deaths within the first 2 years appeared insufficient to minimize the impact of reserve causation bias. [ABSTRACT FROM AUTHOR]

Natural disasters affect structural health of buildings, thus directly impacting public safety. Continuous structural monitoring can be achieved by deploying an Internet of things network of distributed sensors in buildings to capture floor movement. These sensors can be used to compute the displacements of each floor, which can then be employed to assess building damage after a seismic event. The peak relative floor displacement is computed, which is directly related to damage level according to the United States federal agencies standards. With this information, the building inventory can be classified into immediate occupancy, life safety, or collapse prevention categories. In this paper, we propose a zero velocity update technique to minimize displacement estimation error. Theoretical derivation and experimental validation are presented. In addition, we investigate modeling sensor error and interstory drift ratio distribution. Moreover, we discuss the impact of sensor error on the achieved building classification accuracy. [ABSTRACT FROM AUTHOR]

Objectives: In this study, we examined patterns of obesity, physical activity (PA), sleep, and screen time in urban American Indian (AI) youth in the 6th-8th grade. Methods: A youth sample (N = 36) from 3 middle schools was recruited to participate in this observational sample of convenience. Youth completed a demographic and screen time survey, measurements of height and weight, and wore a wrist accelerometer continuously for 7 days to assess PA and sleep. Results: Approximately 42% of participants were overweight or obese. Average weekday screen time was 254.7±98.1 minutes. Compared to weekdays, weekend sedentary activity increased (weekday, 159.2±81.1 minutes vs weekend, 204.3±91.7 minutes; p = .03) and vigorous PA (weekday, 20.9±19.1 minutes vs weekend, 5.7±8.1 minutes; p = .0001) and moderate-to-vigorous PA (weekday, 192.65±62.3 minutes vs weekend, 141±71.7 minutes; p = .002) decreased. Compared to weekdays, weekend total sleep time (weekday, 512.8±48.6 minutes vs weekend, 555.3±84.3 minutes; p = .007) and time in bed (weekday, 487.3±49.6 minutes vs weekend, 528.6±71.2 minutes; p = .01) increased. Conclusions: Weekday to weekend shifts in PA and sleep must be considered when designing targeted obesity prevention interventions. [ABSTRACT FROM AUTHOR]

Background: Concern for head injuries is widespread and has been reported by the media to be the number one cause of decreased participation in football among the American youth population. Identifying player mechanisms associated with intentional, or purposeful, head impacts should provide critical data for rule modifications, educational programs, and equipment design. Purpose: To investigate the frequency of intentional and unintentional head impacts and to examine the player mechanisms associated with intentional high-magnitude head impacts by comparing the impact mechanism distributions among session type, player position, and ball possession. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Head impact sensors and video footage of 68 players were used to analyze and classify 1319 high-magnitude impacts recorded over 1 season of youth football. Results: In total, 80% of the high-magnitude head impacts were classified as being caused by intentional use of the head. Head-to-head impact was the primary impact mechanism (n = 868; 82.7%) within the 1050 intentional high-magnitude impacts, with classifiable mechanisms, followed by head-to-body (n = 139; 13.2%), head-to-ground (n = 34; 3.2%), and head-to-equipment (n = 9; 0.9%). Head-to-head impacts also accounted for a greater proportion of impacts during practices (n = 625; 88.9%) than games, for linemen (n = 585; 90.3%) than perimeters and backs, and for ball carriers (n = 72; 79.1%) than tacklers. Conclusion: Overall, the majority of high-magnitude head impacts were intentional and resulted from head-to-head contact. The proportion of head-to-head contact was significantly higher for practices than games, linemen than backs and perimeter players, and ball carriers than tacklers. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine the relationship between 2005-2006 National Health and Nutrition Examination Survey (NHANES) accelerometer-determined steps/day and activity counts/day, and between steps/day and estimates of nonwear time (as an indicator of the unmonitored day) and time spent in sedentary behaviors as well as a range of physical activity intensities. Methods: Linear regression models were used to characterize the relationship between steps/day, activity counts/day, estimates of wear time, and intensity categories. Results: 1781 males (mean age = 46.5 years) and 1963 females (mean age = 47.7 years) wore accelerometers 14.0 ± SEM0.06 hours/day. The relationship between steps/day and activity counts/day was positive and strong (R² = .87). The relationship between steps/day and time spent in sedentary behaviors was inverse and moderate (R² = .25). Stronger and positive relationships were apparent between steps/day and time in light (R² = .69) and moderate (R² = .63) intensity activities. There was no discernable relationship between steps/day and time spent in low or vigorous intensity activities or with wear time. Conclusions: Assessed by accelerometer, steps/day explains 87% of the variation in activity counts/day, 25% of the variation in time in sedentary behaviors, 69% of time in light intensity, and 63% of time in moderate intensity. [ABSTRACT FROM AUTHOR]

Background: To determine if there are differences in time spent in physical activity and sedentary behavior between rural African American and Caucasian children. Methods: Children wore accelerometers for 3 weekdays. The students were randomly selected from a larger sample of children participating in a weight gain prevention intervention. Usable data were obtained from 272 of the 310 students who agreed to participate. The outcome data included counts per minute (CPM), time spent in moderate to vigorous (MVPA), light (LPA), and sedentary (SED) activity. The equation and cutoff used to analyze national accelerometry data were used for the current study. Results: The sample had an average age of 10.4 (1.1) years and 76% were African American. Lower SES African Americans had more CPM (P = .012) and spent more time in MVPA (P = .008) compared with middle SES African American and lower SES Caucasian children. Lower SES African American children also spent fewer minutes in SED activity (P = .044) compared with middle SES African American children. Conclusions: These findings support recent results that also used objective activity measures. Children appeared less active and more sedentary than a national sample, warranting interventions in minority and rural populations. [ABSTRACT FROM AUTHOR]

Many adolescents do not meet public health recommendations for moderate-tovigorous physical activity (MVPA). In studies of variables influencing adolescent MVPA, one that has been understudied is the affective response to exercise. We hypothesized that adolescents with a more positive affective response to acute exercise would be more active. Adolescents (N = 124; 46% male) completed two 30-min exercise tasks (above and below the ventilatory threshold [VT]), and wore ActiGraph accelerometers for 6.5 ± 0.7 days. Affective valence was assessed before, during, and after each task. A more positive affective response during exercise below the VT was associated with greater participation in MVPA (p < .05). The results are consistent with the hypothesis that individuals who have a more positive affective response to exercise will engage in more MVPA. To promote greater participation in MVPA among adolescents, programs should be designed to facilitate a positive affective experience during exercise. [ABSTRACT FROM AUTHOR]

Evaluates the validity of Computer Science and Applications Inc. (CSA) accelerometer for estimating physical activity in Michigan. Assessment of teenage male basketball players during practice; Criterion measures used in the study; Correlation between CSA and heart rate monitoring.

Evaluates the use of Computer Science and Applications (CSA) accelerometer in measuring the physical activity of preschool children in the U.S. Correlation between CSA output and Children's Physical Activity Form score; Differences in CSA output between left and right hip; Assessment on the efficacy of CSA as tool for physical activity evaluation.

Introduction: Compositional data analysis is one appropriate method for co-dependent data, even when data are collected for a subdivision of the 24-hour period, such as the waking day. Objectives were to use compositional analyses to examine the combined and relative associations of sedentary time (ST), light-intensity physical activity (LPA), moderate-intensity physical activity (MPA), and vigorous-intensity physical activity (VPA) with cardiometabolic biomarkers in a representative sample of children and youth. Methods: This cross-sectional study included 2544 participants aged 6–17 years from the 2003–2006 United States National Health and Nutrition Examination Survey. ST (<100 counts per minute), LPA (100 counts per minute to <4 METs; Freedson age-specific equation), MPA (4 to <7 METs), and VPA (≥7 METs) were accelerometer-derived. Cardiometabolic biomarkers included waist circumference, body mass index (BMI) z-score, HDL-cholesterol, C-reactive protein, and blood pressure. Triglycerides, glucose, insulin, and LDL-cholesterol were measured in a fasting sub-sample of adolescents (n = 670). Compositional linear regression models were conducted. Results: The composition of ST, LPA, MPA, and VPA was significantly associated with BMI z-score, log waist circumference, systolic and diastolic blood pressure, HDL-cholesterol, and log plasma glucose (variance explained: 1–29%). Relative to the other three behaviors, VPA was negatively associated with BMI z-score (γVPA = -0.206, p = 0.005) and waist circumference (γVPA = -0.03, p = 0.001). Conversely, ST was positively associated with waist circumference (γST = 0.029, p = 0.013). ST and VPA were also positively associated with diastolic blood pressure (γST = 2.700, p = 0.018; γVPA = 1.246, p = 0.038), relative to the other behaviors, whereas negative associations were observed for LPA (γLPA = -2.892, p = 0.026). Finally, VPA was positively associated with HDL-cholesterol, relative to other behaviors (γVPA = 0.058, p<0.001). Conclusions: The ST and physical activity composition appears important for many aspects of cardiometabolic health in children and youth. Compositions with more time in higher-intensity activities may be better for some aspects of cardiometabolic health. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Purpose: Physical activity and sedentary behavior among diverse Hispanic/Latino youth in the United States is not well documented. The aim of this study was to describe physical activity and sedentary behavior among a representative sample of Hispanic/Latino youth from four US communities using accelerometry and self-reported measures. Methods: From 2012 to 2014, 1466 Hispanic/Latino youth ages 8 to 16 yr, children of participants in the Hispanic Community Health Study/Study of Latinos, enrolled in the SOL youth. Physical activity and sedentary behavior were assessed by interview. After this, youth wore an Actical accelerometer for 1 wk. All statistical analyses accounted for the complex survey design and used sampling weights. Results: The accelerometer wear time adjusted mean minutes per day was: 604.6, sedentary; 178.9, light; 25.4, moderate; and 10.2, vigorous. Generally, higher levels of moderate and vigorous activity occurred among males, Mexican backgrounds, and youth age 8 to 10 yr compared with older age groups. Higher levels of sedentary behavior occurred among youth age 15 to 16 yr compared with younger age groups. The most common activities (reported, ≥1 per month) were of lower intensity, including listening to music (91.9%), homework (87.0%), riding in car/bus (84.3%), and hanging out with friends (83.4%). Common active pursuits included travel by walking (74.6%), physical education class (71.7%), running (71.4%), and recess (71.3%). Conclusions: Time, intensity, and type of physical activity and sedentary behavior varied among Hispanic/Latino youth. These findings can inform efforts to increase physical activity and reduce sedentary behavior among US Hispanic/Latino youth. [ABSTRACT FROM AUTHOR]

Objective: Inactive lifestyles contribute to health problems and premature death and are influenced by the physical environment. The primary objective of this study was to quantify patterns of physical inactivity in New York City and the United States by combining data from surveys and accelerometers. Methods: We used Poisson regression models and self-reported survey data on physical activity and other demographic characteristics to predict accelerometer-measured inactivity in New York City and the United States among adults aged ≥18. National data came from the 2003-2004 and 2005-2006 National Health and Nutrition Examination Surveys. New York City data came from the 2010-2011 New York City Physical Activity and Transit survey. Results: Self-reported survey data indicated no significant differences in inactivity between New York City and the United States, but accelerometer data showed that 53.1% of persons nationally, compared with 23.4% in New York City, were inactive (P <.001). New Yorkers reported a median of 139 weekly minutes of transportation activity, compared with 0 minutes nationally. Nationally, 50.0% of self-reported activity minutes came from recreation activity, compared with 17.5% in New York City. Regression models indicated differences in the association between self-reported minutes of transportation and recreation and accelerometer-measured inactivity in the 2 settings. Conclusions: The prevalence of physical inactivity was higher nationally than in New York City. The largest difference was in walking behavior indicated by self-reported transportation activity. The study demonstrated the feasibility of combining accelerometer and survey measurement and that walkable environments promote an active lifestyle. [ABSTRACT FROM AUTHOR]

Water polo is a contact sport that is gaining popularity in the United States and carries a risk of repeated head impacts and concussion. The frequency and magnitude of sport-related head impacts have not been described for water polo. We aimed to compare patterns of empirically measured head impact exposure of male collegiate water polo players to patterns previously reported by a survey of current and former water polo athletes. Participants wore water polo caps instrumented with head impact sensors during three seasons of collegiate water polo. Peak linear acceleration (PLA) and peak rotational acceleration (PRA) were recorded for head impacts. Athlete positions were recorded by research staff at the occurrence of each head impact. Head impacts were sustained by athletes in offensive positions more frequently than in defensive and transition positions (246, 59.9% vs. 93, 22.6% vs. 72, 17.5%). 37% of all head impacts during gameplay were sustained by athletes playing the offensive center position. Impact magnitude (means ± SD: PLA = 36.1±12.3g, PRA = 5.0±2.9 krads/sec2) did not differ between position or game scenario. Among goalies, impact frequency and magnitude were similar between games (means ± SD: 0.54±.51 hits/game, PLA = 36.9±14.2g, PRA = 4.3±4.2 krads/sec2) and practices (means ± SD: 0.96±1.11 hits/practice, PLA = 43.7±14.5g, PRA = 3.9±2.5 krads/sec2). We report that collegiate water polo athletes are at risk for sport-related head impacts and impact frequency is dependent on game scenario and player position. In contrast, magnitude does not differ between scenarios or across positions. [ABSTRACT FROM AUTHOR]

OBJECTIVES To evaluate the effect of hospitalizations on patterns of sedentary and physical activity time in mobility‐limited older adults randomized to structured physical activity or health education. DESIGN Secondary analysis of investigator‐blinded, parallel‐group, randomized trial conducted at 8 U.S. centers between February 2010 and December 2013. PARTICIPANTS Sedentary men and women aged 70 to 89 at baseline who wore a hip‐fitted accelerometer 7 consecutive days at baseline and 6, 12, and 24 months after randomization (N=1,341). MEASUREMENTS Participants were randomized to a physical activity (PA; n = 669) intervention that included aerobic, resistance, and flexibility training or to a health education (HE; n = 672) intervention that consisted of workshops on older adult health and light upper‐extremity stretching. Accelerometer patterns were characterized as bouts of sedentary (<100 counts/min; ≥1, ≥10, ≥30, ≥60 minute lengths) and activity (≥100 counts/min; ≥1, ≥2, ≥5, ≥10 minute lengths) time. Each participant was categorized as having 0, 1 to 3, or 4 or more cumulative hospital days before each accelerometer assessment. RESULTS: Hospitalization increased sedentary time similarly in both intervention groups (8 min/d for 1–3 cumulative hospital days and 16 min/d for ≥4 cumulative hospital days). Hospitalization was also associated with less physical activity time across all bouts of less than 10 minutes (≥1: −7 min/d for 1–3 cumulative hospital days, –16 min/d for ≥4 cumulative hospital days; ≥2: −5 min/d for 1–3 cumulative hospital days, −11 min/d for ≥4 cumulative hospital days; ≥5: −3 min/d for 1–3 cumulative hospital days, −4 min/d for ≥4 cumulative hospital days). There was no evidence of recovery to prehospitalization levels (time effect p >.41). PA participants had less sedentary time in bouts of less than 30 minutes than HE participants (−8 to −10 min/d) and more total activity (+3 to +6 min/d), although hospital‐related changes were similar between the intervention groups (interaction effect p >.26). CONCLUSION: Participating in a PA intervention before hospitalization had expected benefits, but participants remained susceptible to hospitalization's detrimental effects on their daily activity levels. There was no evidence of better activity recovery after hospitalization. J Am Geriatr Soc 67:261–268, 2019. [ABSTRACT FROM AUTHOR]

Objective. We evaluated the specific association between muscle-strengthening activity (MSA) and accelerometer-assessed physical activity on systemic inflammation among retinopathy patients in the United States. Methods. Data from the 2005-2006 National Health and Nutrition Examination Survey (NHANES) were used to identify 157 retinopathy patients between 40 and 85 years of age with complete data on select study variables. MSA was assessed via self-report. Participation in moderate-tovigorous physical activity (MVPA) was determined from objective accelerometer data. Systemic inflammation was assessed using C-reactive protein (CRP), which was quantified using latex-enhanced nephelometry. Nonproliferative retinopathy was determined using Early Treatment Diabetic Retinopathy Study grading criteria, as well as objective retinal imaging assessments using the Canon Non-Mydriatic Retinal Camera CR6-45NM. Individuals were excluded if they had been diagnosed with coronary artery disease, congestive heart failure, heart attack, or stroke. Results. MVPA (β = -0.004, 95% CI -0.007 to -0.001, P = 0.006) but not MSA (β = -0.0001, 95% CI -0.002 to 0.001, P = 0.86) was associated with lower CRP levels. Additionally, for a more substantive 30 minutes/day increase in MVPA, there was a corresponding 0.12 mg/dL decrease in CRP. Conclusion. In this nationally representative sample of adults, only individuals who engaged in higher levels of MVPA had lower CRP levels, which is indicative of reduced systemic inflammation. MSA was not associated with systemic inflammation among this cohort. Our findings suggest that MVPA is inversely associated with systemic inflammation among retinopathy patients, which is noteworthy because increased systemic inflammation may facilitate retinopathic severity. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to examine how accelerometer-assessed physical activity accumulation patterns (e.g., is activity performed daily or only 1 or 2 d·wk−1 or is activity accrued in bouts) may affect the association with mortality. Methods: Adults (N = 3438), age 40 yr and older, who wore an accelerometer (ActiGraph 7164), were drawn from the longitudinal follow-up of the National Health and Nutritional Examination Survey (2003–2006), a population-based survey of the United States. Accelerometer-assessed moderate-to-vigorous physical activity (MVPA) was described by activity patterns. Participants engaging in the majority of their activity on only 1 or 2 d·wk−1· were classified as "weekend warriors." Activity bouts were defined as a period of at least moderate intensity lasting at least 10 min. Bout characteristics included bout frequency and length. Mortality was assessed through National Death Index matching through 2013. Mortality rates were compared among groups with different activity patterns. Results: Over an average follow-up of 77.4 months, 394 deaths occurred. Compared to participants with <37.5 min of MVPA per week, those with greater amounts of activity had a 60% to 69% mortality rate reduction after adjusting for relevant covariables. Similar risk reductions were found when contrasting weekend warriors with those who were more frequently active. An increase of one MVPA bout per week was associated with a 13% increased mortality rate. Bout duration was not associated with mortality. Conclusion: Physical activity is associated with decreased mortality rate, even among those who are active 1 or 2 d·wk−1. [ABSTRACT FROM AUTHOR]

The purpose of this study was to consider the feasibility, reliability, and validity of MotionWatch 8. A total of 249 residents were recruited from 26 assisted living settings. Data collection included demographics, comorbidities, function (Barthel Index), physical activity (MotionWatch 8), and falls. The mean age of participants was 86.86 (SD = 7.0), the majority were women 179 (74%) and White (N = 232, 96%). A total of 86% of participants wore the MotionWatch 8. There were no significant differences in physical activity over 3 days of testing. The MotionWatch 8 findings were significantly associated with activities of daily living (ADL) function. There were no significant differences in ADL function or physical activity between those who did and did not fall. The study provides additional support for the feasibility, reliability, and validity of the MotionWatch 8 and confirms that older adults living in assisted living settings spend the majority of their time in sedentary activity. [ABSTRACT FROM AUTHOR]

More than 50% of U.S. adults do not engage in sufficient physical activity to meet current recommendations, making physical activity change and maintenance a priority for health promotion throughout adulthood. Among married partners, change in physical activity of one partner often is concordant with change of activity of the other. The primary purpose of this study was to examine two couple-focused interventions that capitalize on the co-occurrence of health behavior change within couples to promote physical activity in older adults. In this study, partners (N = 31 couples) participated together in assessment and intervention activities, and were randomized together into one of two couple-focused conditions. In one condition (concurrent), standard goal-setting techniques were extended to a couple-focused design with each partner setting daily step goals and monitoring her or his own progress. In the other condition (combined), partners collaborated to set and monitor shared daily step goals. Physical activity was assessed with accelerometers pre- and post-intervention. Post-intervention, average weekly physical activity increased by 58 min (p < 0.001), and average body mass index (BMI) decreased by 0.50 kg/m2 (p = 0.001), from pre-intervention measures. Similar levels of change in weekly physical activity and in BMI were detected in both intervention groups. Furthermore, participants demonstrated high adherence to the intervention protocol. Results suggest that couple-focused physical activity interventions can be effective in eliciting increases in physical activity among older adults. Further research is needed to uncover interpersonal mechanisms that maximize physical activity promotion and maintenance within couples over time. [ABSTRACT FROM AUTHOR]