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Introduction: Physical inactivity, hereafter inactivity, is a serious health problem among U.S. veterans, hereafter veterans. Inactive adults are at risk for adverse cardiac events and premature mortality. Specifically, among veterans, inactivity has been associated with a 23% increase in mortality. In order to increase physical activity among veterans, we developed Veterans Affairs (VA) MapTrek, a mobile-phone-based web app that allows users to take a virtual walk in interesting locations around the world while tracking their progress against that of others like themselves on an interactive map. Steps are counted by a commercially available Fitbit triaxial accelerometer, and users see their progress along a predefined scenic path overlaid on Google Maps. The objective of this study was to determine the effectiveness of VA MapTrek to increase physical activity in a population of veterans at risk for obesity-related morbidity., Materials and Methods: We recruited overweight and obese veterans obtaining care at the Iowa City Veterans Affairs Health Center. Half of the veterans were assigned to participate in VA MapTrek. Each week, participants were assigned virtual walking races (Monday through Saturday), which followed a predetermined route that is displayed on Google Maps. The participant's position on the map is automatically updated each time their Fitbit syncs to their phone. In addition, challenges were issued periodically. Veterans in the control group were only given a Fitbit. We regressed daily step counts on the days of the week, the days since the start of the intervention period, whether the user was in the VA MapTrek or Control group, and an interaction between the study group and the days since the start of the intervention period. We included subject-specific random intercepts and subject-specific random slopes. This model was estimated using Bayesian Hamiltonian Monte Carlo using Stan's No-U-Turns sampler. We set vague, uniform priors on all the parameters., Results: We enrolled 276 participants, but only 251 (102 in the control group and 149 in the VA MapTrek group) contributed data during the intervention period. Our analysis suggests an 86.8% likelihood that the VA MapTrek intervention led to a minimum increase of 1,000 daily steps over the 8-week period, compared to the control group. Throughout the 8-week intervention, we project that VA MapTrek participants would have taken an extra 96,627 steps, equivalent to 77.8 additional kilometers (km) (48.3 additional miles), assuming an average of 1,242 steps per km (2,000 steps per mile)., Conclusions: Our study underscores the potential of VA MapTrek as an intervention for promoting walking among veterans who face elevated risks of obesity and cardiac issues. Rural veterans are a high-risk population, and new interventions like VA MapTrek are needed to improve veterans' health., (© Oxford University Press 2024.)

Importance: Difficulties in identifying modifiable risk factors associated with daily physical activity may impede public health efforts to mitigate the adverse health outcomes of a sedentary lifestyle in an aging population., Objective: To test the hypothesis that adding baseline sensor-derived mobility metrics to diverse baseline motor and nonmotor variables accounts for the unexplained variance of declining daily physical activity among older adults., Design, Setting, and Participants: This cohort study analyzed data from participants of the Rush Memory and Aging Project (MAP), an ongoing longitudinal clinical pathological study that began to enroll older adults (age range, 59.4-104.9 years) in 1997. Wrist- and waist-worn sensors were added to MAP in 2005 and 2012, respectively, to record participants' physical activity and mobility performances. Included participants were examined at baseline and annually followed up for a mean (SD) duration of 4.2 (1.6) years., Exposure: Twelve blocks of variables, including 3 blocks of mobility metrics derived from recordings of a belt-worn sensor to quantify a 32-foot walk, a Timed Up and Go (TUG) test, and a standing balance task, and 9 other blocks with 41 additional variables., Main Outcomes and Measures: A linear mixed-effects model was used to estimate the person-specific rate of change (slope) of total daily physical activity obtained from a wrist-worn sensor. Twelve linear regression models were used to estimate the adjusted R2 to quantify the associations of the variables with the slope., Results: A total of 650 older adults (500 females [76.9%]; mean [SD] age at baseline, 81.4 [7.5] years; 31 Black individuals [4.8%], 17 Latino individuals [2.6%], and 602 White individuals [92.6%]) were included. During follow-up, all but 1 participant showed declining daily physical activity, which was equivalent to approximately 16.8% decrease in activity level per year. In separate models, waist sensor-derived mobility metrics (32-foot walk: adjusted R2, 23.4% [95% CI, 17.3%-30.6%]; TUG test: adjusted R2, 22.8% [95% CI, 17.7%-30.1%]) and conventional motor variables (adjusted R2, 24.1% [95% CI, 17.7%-31.4%]) had the largest percentages of variance of declining daily physical activity compared with nonmotor variables. When the significant variables from all 12 blocks were included together in a single model, only turning speed (estimate [SE], 0.018 [0.006]; P = .005) and hand dexterity (estimate [SE], 0.091 [0.034]; P = .008) showed associations with declining daily physical activity., Conclusions and Relevance: Findings of this study suggest that sensor-derived mobility metrics and conventional motor variables compared with nonmotor measures explained most of the variance of declining daily physical activity. Further studies are needed to ascertain whether improving specific motor abilities, such as turning speed and hand dexterity, is effective in slowing the decline of daily physical activity in older adults.

Background: Randomised, cluster-based study designs in schools are commonly used to evaluate children's physical activity interventions. Sample size estimation relies on accurate estimation of the intra-cluster correlation coefficient (ICC), but published estimates, especially using accelerometry-measured physical activity, are few and vary depending on physical activity outcome and participant age. Less commonly-used cluster-based designs, such as stepped wedge designs, also need to account for correlations over time, e.g. cluster autocorrelation (CAC) and individual autocorrelation (IAC), but no estimates are currently available. This paper estimates the school-level ICC, CAC and IAC for England children's accelerometer-measured physical activity outcomes by age group and gender, to inform the design of future school-based cluster trials., Methods: Data were pooled from seven large English datasets of accelerometer-measured physical activity data between 2002-18 (> 13,500 pupils, 540 primary and secondary schools). Linear mixed effect models estimated ICCs for weekday and whole week for minutes spent in moderate-to-vigorous physical activity (MVPA) and being sedentary for different age groups, stratified by gender. The CAC (1,252 schools) and IAC (34,923 pupils) were estimated by length of follow-up from pooled longitudinal data., Results: School-level ICCs for weekday MVPA were higher in primary schools (from 0.07 (95% CI: 0.05, 0.10) to 0.08 (95% CI: 0.06, 0.11)) compared to secondary (from 0.04 (95% CI: 0.03, 0.07) to (95% CI: 0.04, 0.10)). Girls' ICCs were similar for primary and secondary schools, but boys' were lower in secondary. For all ages, combined the CAC was 0.60 (95% CI: 0.44-0.72), and the IAC was 0.46 (95% CI: 0.42-0.49), irrespective of follow-up time. Estimates were higher for MVPA vs sedentary time, and for weekdays vs the whole week., Conclusions: Adequately powered studies are important to evidence effective physical activity strategies. Our estimates of the ICC, CAC and IAC may be used to plan future school-based physical activity evaluations and were fairly consistent across a range of ages and settings, suggesting that results may be applied to other high income countries with similar school physical activity provision. It is important to use estimates appropriate to the study design, and that match the intended study population as closely as possible., (© 2024. The Author(s).)

Background: Too much sedentary behavior (SB) and too little physical activity (PA) place adult workers at risk for chronic illness. It remains unclear which occupations and subgroups within occupations have the highest and lowest SB and PA, and little is known about the effects of organizational factors on these behaviors and metrics. Thus, our main aims were to review and summarize evidence describing daily SB and PA collected using accelerometry across various occupations and to identify organizational factors influencing SB and PA., Methods: A literature search of six databases was performed for relevant studies published through March 2023. Eligible studies were in English, targeted working populations, had a sample size > 75, and objectively measured both SB and PA for seven consecutive days using accelerometers. Following PRISMA guidelines, 5,197 studies were identified, and 19 articles met our inclusion criteria. Five of these studies were included in a meta-analysis comparing time spent in SB, light PA (LPA), and moderate to vigorous PA (MVPA) across occupations. Methodological quality was assessed using a Joanna Briggs Institute tool., Results: We found that 63% of the studies reported daily time spent in SB and in MVPA, but fewer reported LPA, moderate PA, and vigorous PA. The average time spent in SB was 553.34 min/day, in LPA was 299.77 min/day, and in MVPA was 33.87 min/day. In occupational subgroup analysis, we observed that office workers had 2.3 h more SB, 2.4 less hours LPA, and 14 min less MVPA per day than nurses. However, most studies either did not specify workers' occupations or grouped occupations. Shift work and workplace facilities significantly influenced SB and PA, but organizational factors affecting these behaviors were not sufficiently investigated (e.g., occupation type, work environment and workplace facilities, and shift work)., Conclusions: More research is needed to explore SB and PA patterns within occupational subgroups. Additionally, it is important to explore work-related individual (e.g., job task), interpersonal (e.g., social support from colleagues), organizational (e.g., work policy), and environmental factors influencing SB and PA. Future studies should also investigate the association of these factors with SB and PA., (© 2024. The Author(s).)

Introduction: The U.S. Marine Corps (USMC) recruit training is a 13-week preparatory period for military service men and women. Differences in absolute performance capabilities between sexes may impact physical and physiological responses to the demands of recruit training. The purpose of this study was to monitor U.S. Marine Corps recruits throughout recruit training to comparatively assess workload, sleep, stress, and performance responses in men and women., Materials and Methods: A total of 281 recruits (men = 182 and women = 99; age = 19 ± 2 years) were monitored and tested. Workload, sleep, and stress assessments occurred at week 2, week 7/8, and week 11 of training. Workload (energy expenditure per kg body mass [EEREL], distance [DIS], steps) and sleep (continuity and duration) were tracked over 72-hour periods using wearable accelerometry and heart rate technology. Stress responses were determined through salivary cortisol analyses. Performance testing, consisting of countermovement vertical jump (CMJ) and isometric mid-thigh pull (IMTP) performance relative to body mass, occurred at weeks 2 and 11. Linear mixed models were used to test for sex, time, and sex-by-time interactions (α < .05)., Results: On average, recruits covered 13.0 ± 2.7 km/day, expended 3,762 ± 765 calories/day, and slept 6.2 ± 1.1 hours/night. Sex-by-time interactions were found for DIS, steps, sleep duration, cortisol, and CMJREL performance (P < .05). Planned contrasts revealed that men covered more DIS than women at week 7/8 (P < .001). Women experienced greater step counts compared to men at week 11 (P = .004). Women experienced no significant change in sleep duration (P > .05), whereas men increased sleep duration from week 2 to week 7/8 (P = .03). Women experienced greater sleep duration at week 2 (P = .03) and week 11 (P = .02) compared to men. Women exhibited higher cortisol levels than men at week 2 (P < .001) and week 11 (P < .001). Women experienced declines in cortisol at week 7 compared to week 2 (P < .001). Men experienced no changes in cortisol response at any timepoint (P > .05). Both sexes experienced declines in CMJREL from week 2 to week 11 (P > .001). Sex main effects were observed for EEREL, DIS, CMJREL, and IMTPREL (P < .05) with men experiencing greater overall workloads and producing greater strength and power metrics. Sex main effects were also found for sleep continuity and cortisol (P < .05), for which men experienced lower values compared to women. Time main effects were observed for EEREL, DIS, steps, cortisol, CMJREL, and IMTPREL (P < .05)., Conclusions: This study not only highlights the known sex differences between men and women but also sheds light on the different physical and physiological responses of each sex to military training. Interestingly, the greatest physical demands incurred earlier in the training cycle. Despite declining workloads, the stress response was maintained throughout the training, which may have implications for adaptation and performance. In addition, average sleep duration fell notably below recommendations for optimizing health and recovery. Effectively monitoring the demands and performance outcomes during recruit training is essential for determining individual fitness capabilities, as well as establishing the effectiveness of a training program. Individual performance assessments and adequately periodized workloads may help to optimize recruit training for both men and women., (© The Association of Military Surgeons of the United States 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

Accelerometers, devices that measure body movements, have become valuable tools for studying the fragmentation of rest-activity patterns, a core circadian rhythm dimension, using metrics such as inter-daily stability (IS), intradaily variability (IV), transition probability (TP), and self-similarity parameter (named α ). However, their use remains mainly empirical. Therefore, we investigated the mathematical properties and interpretability of rest-activity fragmentation metrics by providing mathematical proofs for the ranges of IS and IV, proposing maximum likelihood and Bayesian estimators for TP, introducing the activity balance index (ABI) metric, a transformation of α , and describing distributions of these metrics in real-life setting. Analysis of accelerometer data from 2,859 individuals (age=60-83 years, 21.1% women) from the Whitehall II cohort (UK) shows modest correlations between the metrics, except for ABI and α . Sociodemographic (age, sex, education, employment status) and clinical (body mass index (BMI), and number of morbidities) factors were associated with these metrics, with differences observed according to metrics. For example, a difference of 5 units in BMI was associated with all metrics (differences ranging between -0.261 (95% CI -0.302, -0.220) to 0.228 (0.18, 0.268) for standardised TP rest to activity during the awake period and TP activity to rest during the awake period, respectively). These results reinforce the value of these rest-activity fragmentation metrics in epidemiological and clinical studies to examine their role for health. This paper expands on a set of methods that have previously demonstrated empirical value, improves the theoretical foundation for these methods, and evaluates their empirical use in a large dataset., (© 2024. The Author(s).)

Importance: Guidelines recommend 150 minutes or more of moderate to vigorous physical activity (MVPA) per week for overall health benefit, but the relative effects of concentrated vs more evenly distributed activity are unclear., Objective: To examine associations between an accelerometer-derived "weekend warrior" pattern (ie, most MVPA achieved over 1-2 days) vs MVPA spread more evenly with risk of incident cardiovascular events., Design, Setting, and Participants: Retrospective analysis of UK Biobank cohort study participants providing a full week of accelerometer-based physical activity data between June 8, 2013, and December 30, 2015., Exposures: Three MVPA patterns were compared: active weekend warrior (active WW, ≥150 minutes with ≥50% of total MVPA achieved in 1-2 days), active regular (≥150 minutes and not meeting active WW status), and inactive (<150 minutes). The same patterns were assessed using the sample median threshold of 230.4 minutes or more of MVPA per week., Main Outcomes and Measures: Associations between activity pattern and incident atrial fibrillation, myocardial infarction, heart failure, and stroke were assessed using Cox proportional hazards regression, adjusted for age, sex, racial and ethnic background, tobacco use, alcohol intake, Townsend Deprivation Index, employment status, self-reported health, and diet quality., Results: A total of 89 573 individuals (mean [SD] age, 62 [7.8] years; 56% women) who underwent accelerometry were included. When stratified at the threshold of 150 minutes or more of MVPA per week, a total of 37 872 were in the active WW group (42.2%), 21 473 were in the active regular group (24.0%), and 30 228 were in the inactive group (33.7%). In multivariable-adjusted models, both activity patterns were associated with similarly lower risks of incident atrial fibrillation (active WW: hazard ratio [HR], 0.78 [95% CI, 0.74-0.83]; active regular: 0.81 [95% CI, 0.74-0.88; inactive: HR, 1.00 [95% CI, 0.94-1.07]), myocardial infarction (active WW: 0.73 [95% CI, 0.67-0.80]; active regular: 0.65 [95% CI, 0.57-0.74]; and inactive: 1.00 [95% CI, 0.91-1.10]), heart failure (active WW: 0.62 [95% CI, 0.56-0.68]; active regular: 0.64 [95% CI, 0.56-0.73]; and inactive: 1.00 [95% CI, 0.92-1.09]), and stroke (active WW: 0.79 [95% CI, 0.71-0.88]; active regular: 0.83 [95% CI, 0.72-0.97]; and inactive: 1.00 [95% CI, 0.90-1.11]). Findings were consistent at the median threshold of 230.4 minutes or more of MVPA per week, although associations with stroke were no longer significant (active WW: 0.89 [95% CI, 0.79-1.02]; active regular: 0.87 [95% CI, 0.74-1.02]; and inactive: 1.00 [95% CI, 0.90-1.11])., Conclusions and Relevance: Physical activity concentrated within 1 to 2 days was associated with similarly lower risk of cardiovascular outcomes to more evenly distributed activity.

Background: Given the evolution of processing and analysis methods for accelerometry data over the past decade, it is important to understand how newer summary measures of physical activity compare with established measures., Objective: We aimed to compare objective measures of physical activity to increase the generalizability and translation of findings of studies that use accelerometry-based data., Methods: High-resolution accelerometry data from the Baltimore Longitudinal Study on Aging were retrospectively analyzed. Data from 655 participants who used a wrist-worn ActiGraph GT9X device continuously for a week were summarized at the minute level as ActiGraph activity count, monitor-independent movement summary, Euclidean norm minus one, mean amplitude deviation, and activity intensity. We calculated these measures using open-source packages in R. Pearson correlations between activity count and each measure were quantified both marginally and conditionally on age, sex, and BMI. Each measures pair was harmonized using nonparametric regression of minute-level data., Results: Data were from a sample (N=655; male: n=298, 45.5%; female: n=357, 54.5%) with a mean age of 69.8 years (SD 14.2) and mean BMI of 27.3 kg/m2 (SD 5.0). The mean marginal participant-specific correlations between activity count and monitor-independent movement summary, Euclidean norm minus one, mean amplitude deviation, and activity were r=0.988 (SE 0.0002324), r=0.867 (SE 0.001841), r=0.913 (SE 0.00132), and r=0.970 (SE 0.0006868), respectively. After harmonization, mean absolute percentage errors of predicting total activity count from monitor-independent movement summary, Euclidean norm minus one, mean amplitude deviation, and activity intensity were 2.5, 14.3, 11.3, and 6.3, respectively. The accuracies for predicting sedentary minutes for an activity count cut-off of 1853 using monitor-independent movement summary, Euclidean norm minus one, mean amplitude deviation, and activity intensity were 0.981, 0.928, 0.904, and 0.960, respectively. An R software package called SummarizedActigraphy, with a unified interface for computation of the measures from raw accelerometry data, was developed and published., Conclusions: The findings from this comparison of accelerometry-based measures of physical activity can be used by researchers and facilitate the extension of knowledge from existing literature by demonstrating the high correlation between activity count and monitor-independent movement summary (and other measures) and by providing harmonization mapping., (©Marta Karas, John Muschelli, Andrew Leroux, Jacek K Urbanek, Amal A Wanigatunga, Jiawei Bai, Ciprian M Crainiceanu, Jennifer A Schrack. Originally published in JMIR mHealth and uHealth (https://mhealth.jmir.org), 22.07.2022.)

Background: One of the mechanisms suggested to link physical activity (PA) to favorable brain health is through stimulation of neural growth factors such as brain-derived neurotrophic factor (BDNF). Acute bouts of PA stimulate circulating BDNF levels., Objective: In this investigation, we assessed whether habitual, accelerometer-measured PA levels were related to circulating BDNF levels in a middle-aged cohort., Methods: In the Framingham Heart Study Third Generation cohort, 1,769 participants provided reliable accelerometry data and were not missing BDNF measurement or platelet counts. In a cross-sectional analysis, using multivariable regression, we related PA measures to serum BDNF levels, adjusting for age, sex, smoking status, platelet count, depression status, and accelerometer wear time., Results: Our study participants (mean age 47±9 years, 50.8% women) spent an average of 22.3 mins/day in moderate-to-vigorous (MV)PA. Most PA variables (steps, MVPA, light activity, and sedentary time) were not related to BDNF levels (p > 0.05). We observed a non-linear trend, where 15-50 mins/week vigorous activity was associated with lower BDNF compared to those with 0 min vigorous activity (β= -0.049±0.024, p = 0.05), but with no significant associations at lower or higher vigorous activity levels. In smokers, MVPA was also associated with lower BDNF levels (β= -0.216±0.079, p = 0.01)., Conclusion: Our study reveals that circulating BDNF is not chronically elevated in individuals with higher levels of habitual PA in middle-aged adults from the community and may even be chronically suppressed with higher PA in subgroups, including current smokers. These results do not contradict previous studies demonstrating that circulating BDNF rises acutely after PA.

To contain the recent COVID-19 outbreak, restrictions have been imposed, which has limited outdoor activity. These physical behavior changes can have serious health implications, but there is little objective information quantifying these changes. This study aimed to estimate the change in physical behavior levels during full lockdown conditions using objective data collected from a thigh-worn activity monitor. Data used were from 6492 individuals in the 1970 British Cohort Study, collected between 2016 and 2018. Using walking bout characteristics, days were classified as either "indoor only" (n = 861), "indoor and exercise" (n = 167), and "outdoor active" (n = 31 934). When compared to "outdoor active" days, "indoor only" days had 6590 fewer steps per day (2320 vs 8876, p < 0.001), a longer sedentary time (1.5 h, p < 0.001), longer lying time (1.4 h, p < 0.001) and shorter standing (1.9 h, p < 0.001) and stepping (1.3 h, p < 0.001) times. The "indoor and exercise" days had a smaller number of steps compared to "outdoor active" (7932 vs 8876, p < 0.05). There is a strong relationship between reduced daily stepping, and increased sedentary time, with a range of poor health outcomes. This has important implications for public health policy and messaging during pandemics., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Importance: Steps per day is a meaningful metric for physical activity promotion in clinical and population settings. To guide promotion strategies of step goals, it is important to understand the association of steps with clinical end points, including mortality., Objective: To estimate the association of steps per day with premature (age 41-65 years) all-cause mortality among Black and White men and women., Design, Setting, and Participants: This prospective cohort study was part of the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were aged 38 to 50 years and wore an accelerometer from 2005 to 2006. Participants were followed for a mean (SD) of 10.8 (0.9) years. Data were analyzed in 2020 and 2021., Exposure: Daily steps volume, classified as low (<7000 steps/d), moderate (7000-9999 steps/d), and high (≥10 000 steps/d) and stepping intensity, classified as peak 30-minute stepping rate and time spent at 100 steps/min or more., Main Outcomes and Measures: All-cause mortality., Results: A total of 2110 participants from the CARDIA study were included, with a mean (SD) age of 45.2 (3.6) years, 1205 (57.1%) women, 888 (42.1%) Black participants, and a median (interquartile range [IQR]) of 9146 (7307-11 162) steps/d. During 22 845 person years of follow-up, 72 participants (3.4%) died. Using multivariable adjusted Cox proportional hazards models, compared with participants in the low step group, there was significantly lower risk of mortality in the moderate (hazard ratio [HR], 0.28 [95% CI, 0.15-0.54]; risk difference [RD], 53 [95% CI, 27-78] events per 1000 people) and high (HR, 0.45 [95% CI, 0.25-0.81]; RD, 41 [95% CI, 15-68] events per 1000 people) step groups. Compared with the low step group, moderate/high step rate was associated with reduced risk of mortality in Black participants (HR, 0.30 [95% CI, 0.14-0.63]) and in White participants (HR, 0.37 [95% CI, 0.17-0.81]). Similarly, compared with the low step group, moderate/high step rate was associated with reduce risk of mortality in women (HR, 0.28 [95% CI, 0.12-0.63]) and men (HR, 0.42 [95% CI, 0.20-0.88]). There was no significant association between peak 30-minute intensity (lowest vs highest tertile: HR, 0.98 [95% CI, 0.54-1.77]) or time at 100 steps/min or more (lowest vs highest tertile: HR, 1.38 [95% CI, 0.73-2.61]) with risk of mortality., Conclusions and Relevance: This cohort study found that among Black and White men and women in middle adulthood, participants who took approximately 7000 steps/d or more experienced lower mortality rates compared with participants taking fewer than 7000 steps/d. There was no association of step intensity with mortality.

Background: Objective measures of physical activity (PA) derived from wrist-worn accelerometers are compared with traditional risk factors in terms of mortality prediction performance in the UK Biobank., Method: A subset of participants in the UK Biobank study wore a tri-axial wrist-worn accelerometer in a free-living environment for up to 7 days. A total of 82 304 individuals over the age of 50 (439 707 person-years of follow-up, 1959 deaths) had both accelerometry data that met specified quality criteria and complete data on a set of traditional mortality risk factors. Predictive performance was assessed using cross-validated Concordance (C) for Cox regression models. Forward selection was used to obtain a set of best predictors of mortality., Results: In univariate Cox regression, age was the best predictor of all-cause mortality (C = 0.681) followed by 12 PA predictors, led by minutes of moderate-to-vigorous PA (C = 0.661) and total acceleration (C = 0.661). Overall, 16 of the top 20 predictors were objective PA measures (C = 0.578-0.661). Using a threshold of 0.001 improvement in Concordance, the Concordance for the best model that did not include PA measures was 0.735 (9 covariates) compared with 0.748 (12 covariates) for the best model with PA variables (p-value < .001)., Conclusions: Objective measures of PA derived from accelerometry outperform traditional predictors of all-cause mortality in the UK Biobank except age and substantially improve the prediction performance of mortality models based on traditional risk factors. Results confirm and complement previous findings in the National Health and Nutrition Examination Survey (NHANES)., (© The Author(s) 2020. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Physical activity (PA) during childhood is important for preventing future metabolic syndrome (MetS). To examine the relationship between PA and MetS in more detail, accurate measures of PA are needed. Previous studies have only utilized a small part of the information available from accelerometer measured PA. This study investigated the association between measured PA and MetS in children with a new method for data processing and analyses that enable more detailed interpretation of PA intensity level., Methods: The association between PA pattern and risk factors related to MetS was investigated in a cross- sectional sample of children (n = 2592, mean age 10.9 years, 49.4% male) participating in the European multicenter I. Family study. The risk factors examined include body mass index, blood pressure, high-density lipoprotein cholesterol, insulin resistance and a combined risk factor score (MetS score). PA was measured by triaxial accelerometers and raw data was processed using the 10 Hz frequency extended method (FEM). The PA output was divided into an intensity spectrum and the association with MetS risk factors was analyzed by partial least squares regression., Results: PA patterns differed between the European countries investigated, with Swedish children being most active and Italian children least active. Moderate intensity physical activity was associated with lower insulin resistance (R 2  = 2.8%), while vigorous intensity physical activity was associated with lower body mass index (R 2  = 3.6%), MetS score (R 2  = 3.1%) and higher high-density lipoprotein cholesterol (R 2  = 2.3%). PA of all intensities was associated with lower systolic- and diastolic blood pressure, although the associations were weaker than for the other risk factors (R 2  = 1.5% and R 2  = 1.4%). However, the multivariate analysis implies that the entire PA pattern must be considered. The main difference in PA was observed between normal weight and overweight children., Conclusions: The present study suggests a greater importance of more PA corresponding to an intensity of at least brisk walking with inclusion of high-intense exercise, rather than a limited time spent sedentary, in the association to metabolic health in children. The methods of data processing and statistical analysis enabled accurate analysis and interpretation of the health benefits of high intensity PA that have not been shown previously.

Background: Moderate-to-vigorous intensity physical activity (MVPA) is associated with favorable self-rated mental and physical health. Conversely, poor self-rated health in these domains could precede unfavorable shifts in activity. We evaluated bidirectional associations of accelerometer-estimated time spent in stationary behavior (SB), light intensity physical activity (LPA), and MVPA with self-rated health over 10 years in in the CARDIA longitudinal cohort study., Methods: Participants (n = 894, age: 45.1 ± 3.5; 63% female; 38% black) with valid accelerometry wear and self-rated health at baseline (2005-6) and 10-year follow-up (2015-6) were included. Accelerometry data were harmonized between exams and measured mean total activity and duration (min/day) in SB, LPA, and MVPA; duration (min/day) in long-bout and short-bout SB (≥30 min vs. < 30 min) and MVPA (≥10 min vs. < 10 min) were also quantified. The Short-Form 12 Questionnaire measured both a mental component score (MCS) and physical component score (PCS) of self-rated health (points). Multivariable linear regression associated baseline accelerometry variables with 10-year changes in MCS and PCS. Similar models associated baseline MCS and PCS with 10-year changes in accelerometry measures., Results: Over 10-years, average (SD) MCS increased 1.05 (9.07) points, PCS decreased by 1.54 (7.30) points, and activity shifted toward greater SB and less mean total activity, LPA, and MVPA (all p < 0.001). Only baseline short-bout MVPA was associated with greater 10-year increases in MCS (+ 0.92 points, p = 0.021), while baseline mean total activity, MVPA, and long-bout MVPA were associated with greater 10-year changes in PCS (+ 0.53 to + 1.47 points, all p < 0.005). In the reverse direction, higher baseline MCS and PCS were associated with favorable 10-year changes in mean total activity (+ 9.75 cpm, p = 0.040, and + 15.66 cpm, p < 0.001, respectively) and other accelerometry measures; for example, higher baseline MCS was associated with - 13.57 min/day of long-bout SB (p < 0.001) and higher baseline PCS was associated with + 2.83 min/day of MVPA (p < 0.001) in fully adjusted models., Conclusions: The presence of bidirectional associations between SB and activity with self-rated health suggests that individuals with low overall activity levels and poor self-rated health are at high risk for further declines and supports intervention programming that aims to dually increase activity levels and improve self-rated health.

Aims: In response to the COVID-19 pandemic, the UK was placed under strict lockdown measures on 23 March 2020. The aim of this study was to quantify the effects on physical activity (PA) levels using data from the prospective Triage-HF Plus Evaluation study., Methods: This study represents a cohort of adult patients with implanted cardiac devices capable of measuring activity by embedded accelerometery via a remote monitoring platform. Activity data were available for the 4 weeks pre-implementation and post implementation of 'stay at home' lockdown measures in the form of 'minutes active per day' (min/day)., Results: Data were analysed for 311 patients (77.2% men, mean age 68.8, frailty 55.9%. 92.2% established heart failure (HF) diagnosis, of these 51.2% New York Heart Association II), with comorbidities representative of a real-world cohort.Post-lockdown, a significant reduction in median PA equating to 20.8 active min/day was seen. The reduction was uniform with a slightly more pronounced drop in PA for women, but no statistically significant difference with respect to age, body mass index, frailty or device type. Activity dropped in the immediate 2-week period post-lockdown, but steadily returned thereafter. Median activity week 4 weeks post-lockdown remained significantly lower than 4 weeks pre-lockdown (p≤0.001)., Conclusions: In a population of predominantly HF patients with cardiac devices, activity reduced by approximately 20 min active per day in the immediate aftermath of strict COVID-19 lockdown measures., Trial Registration Number: NCT04177199., Competing Interests: Competing interests: JKT has previously filled a research post funded by Medtronic, is currently funded by the British Heart Foundation, and receives support as a Peter Mount awardee at Manchester University NHS Foundation Trust. The sponsor/ funder and industry did not have any role in the data analysis or manuscript content. FA has previously received a research grant funded by Medtronic. FA has received consultancy fees from Astrazeneca, Medtronic, Pfizer, Pharmacosmos, Servier and Vifor. MD has no relevant disclosures., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Physical activity has been commonly measured as time spent in bouts of at least 10 minutes, however, each minute of physical activity achieved in a day is now regarded as beneficial. This study aims to compare differences in total time spent walking in a week to time spent walking in 10-minute bouts over the same seven-day period., Methods: Two self-reported measures of time spent walking were compared: one using time-constrained bouts and the other using total minutes. The first measure comes from the validated Active Australia Survey and reports walking in bouts of 10min or more, the second measure reports total estimated time spent walking., Results: Data from 4,582 university participants in a census-styled survey were analysed. When comparing the reported minutes of walking in either 10-minute bouts or total minutes, more walking occurs in short bursts with a difference of 117min/week (p<0.001)., Conclusions: This result shows more walking is reported across a week in short bursts of less than 10 minutes. Implications for public health: To monitor trends and evaluate physical activity interventions, reliable and valid measures of physical activity are necessary. Our result questions the usefulness of reporting bouted-walking as a measure which accurately captures population behaviour., (© 2021 The Authors.)

Abstract: This study aimed to investigate the relationships between omentin-1, body composition and physical activity (PA) levels in older women.Eighty-one older women (age = 64 ± 6years; body mass index = 24.2 ± 3.2 kg/m2; body fat percentage = 36.1 ± 5.7%) participated in this study. We divided the subjects into overweight/obesity and normal weight group. Body composition was measured by dual energy X-ray absorptiometry. Serum omentin-1 concentration was measured using enzyme linked immunosorbent assay. PA levels were obtained by using accelerometers. In addition, anthropometric and insulin resistance values were determined.Omentin-1 level in overweight/obesity group was significantly lower than in the normal weight group (P < .01). Analysis of all subjects showed that serum omentin-1 was negatively correlated with body weight, BMI (body mass index), waist circumference (WC), WHR (waist-to-hip ratio), percentage of body fat, total body fat mass (FM), fat-free mass (FFM) (r = -.571, -0.569, -0.546, -0.382, -0.394, -0.484, -0.524, all P < .01), respectively. We also found a negative correlation between moderate-to-vigorous physical activity (MVPA) and total body FM (r = -.233, P < .05). However, no significant correlation was found between omentin-1 and sedentary behavior and MVPA (both P > .05). Moreover, the relationship between omentin-1, body composition and PA was analyzed by using multiple linear stepwise regressions. The results showed that serum omentin-1 concentration was inversely correlated with total body FM (β = -0.334, P = .004) in multiple linear stepwise regression analysis.We found that total body FM was inversely related to serum omentin-1 concentration and PA levels, but there was no correlation between omentin-1 and PA levels. These results showed that PA may participate in the regulation of body composition, which may be also affected by serum omentin-1. However, the mechanism by which PA affects body composition may not be through omentin-1 and was more likely through other metabolic pathways., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Physical activity (PA) has beneficial effects on health and health-related quality of life (HRQoL), which is a protective factor of illness and mortality. The purpose of this examination was to investigate if self-reported and device-based measures of PA were related to HRQoL in adolescents., Methods: Participants (N = 1565; 54.3% female; M age  = 14.37 years, SD age  = 1.99) were recruited from 167 sample points across Germany. Adolescents self-reported their PA, supplemented by a 1-week examination of device-based PA using accelerometry. Additionally, they completed the multidimensional KIDSCREEN-27 to assess HRQoL., Results: Results showed that self-reported PA was correlated with overall HRQoL, Physical Well-Being, Psychological Well-Being, Social Support & Peers, and School Environment, whereas device-based PA was only correlated with Physical as well as Psychological Well-Being. Further, self-reported PA significantly predicted all facets of HRQoL except for Autonomy and Parent Relations, whereas device-based PA solely heightened the amount of explained variance in the Physical Well-Being subscale., Conclusions: Findings demonstrate the importance of self-reported PA as it is related to almost all facets of HRQoL. Both measures of PA are not congruent in their relationship with HRQoL and thus implications have to be carefully considered. Future studies should investigate the direct effect of PA on HRQoL and health in a longitudinal approach to account for the causality of effects.

Previous studies translating the daily moderate-to-vigorous physical activity (MVPA) recommendation of total steps/day among adolescents are inconsistent, and those with cadence-based steps are scarce. The main purpose was to compare the accuracy of different daily steps index-based cut-points related to the daily 60 minutes of MVPA recommendation measured by a waist-worn accelerometer for adolescents. Following a cross-sectional design, 428 Spanish adolescents (final sample 351, 50.4% males), aged 13-16 years old, wore an ActiGraph GT3X/+ accelerometer (reference standard = MVPA; index tests = total steps/day, average steps/min and peak 1-min cadence) on the right hip for eight consecutive days. 32.5% of the adolescents met the daily MVPA recommendation. The multiple ROC curve comparisons showed that the accuracy of the daily total step-based recommendation (AUC = 0.97) was statistically higher than for those with the steps/min (AUC = 0.90) and peak 1-min cadence (AUC = 0.58) ( p < 0.001). The 10,000-step-per-day cut-point ( k = 0.59-0.83) showed highest accuracy values than the 12,000 steps/day ( k = 0.20-0.32). Daily total step-based recommendations are more accurate than those with steps/min and peak 1-min cadence for classifying adolescents as being physically active or inactive. A 10,000-step-per-day target is simple and accurate for both male and female adolescents.

Accurate and low-cost sleep measurement tools are needed in both clinical and epidemiological research. To this end, wearable accelerometers are widely used as they are both low in price and provide reasonably accurate estimates of movement. Techniques to classify sleep from the high-resolution accelerometer data primarily rely on heuristic algorithms. In this paper, we explore the potential of detecting sleep using Random forests. Models were trained using data from three different studies where 134 adult participants (70 with sleep disorder and 64 good healthy sleepers) wore an accelerometer on their wrist during a one-night polysomnography recording in the clinic. The Random forests were able to distinguish sleep-wake states with an F1 score of 73.93% on a previously unseen test set of 24 participants. Detecting when the accelerometer is not worn was also successful using machine learning ([Formula: see text]), and when combined with our sleep detection models on day-time data provide a sleep estimate that is correlated with self-reported habitual nap behaviour ([Formula: see text]). These Random forest models have been made open-source to aid further research. In line with literature, sleep stage classification turned out to be difficult using only accelerometer data.

Background: The rapid advancements in science and technology of wrist-wearable activity devices offer considerable potential for clinical applications. Self-monitoring of physical activity (PA) with activity devices is helpful to improve the PA levels of adolescents. However, knowing the accuracy of activity devices in adolescents is necessary to identify current levels of PA and assess the effectiveness of intervention programs designed to increase PA., Objective: The study aimed to determine the validity of the 11 commercially available wrist-wearable activity devices for monitoring total steps and total 24-hour total energy expenditure (TEE) in healthy adolescents under simulated free-living conditions., Methods: Nineteen (10 male and 9 female) participants aged 14 to 18 years performed a 24-hour activity cycle in a metabolic chamber. Each participant simultaneously wore 11 commercial wrist-wearable activity devices (Mi Band 2 [XiaoMi], B2 [Huawei], Bong 2s [Meizu], Amazfit [Huamei], Flex [Fitbit], UP3 [Jawbone], Shine 2 [Misfit], GOLiFE Care-X [GoYourLife], Pulse O2 [Withings], Vivofit [Garmin], and Loop [Polar Electro]) and one research-based triaxial accelerometer (GT3X+ [ActiGraph]). Criterion measures were total EE from the metabolic chamber (mcTEE) and total steps from the GT3X+ (AGsteps)., Results: Pearson correlation coefficients r for 24-hour TEE ranged from .78 (Shine 2, Amazfit) to .96 (Loop) and for steps ranged from 0.20 (GOLiFE) to 0.57 (Vivofit). Mean absolute percent error (MAPE) for TEE ranged from 5.7% (Mi Band 2) to 26.4% (Amazfit) and for steps ranged from 14.2% (Bong 2s) to 27.6% (Loop). TEE estimates from the Mi Band 2, UP3, Vivofit, and Bong 2s were equivalent to mcTEE. Total steps from the Bong 2s were equivalent to AGsteps., Conclusions: Overall, the Bong 2s had the best accuracy for estimating TEE and total steps under simulated free-living conditions. Further research is needed to examine the validity of these devices in different types of physical activities under real-world conditions., (©Yingying Hao, Xiao-Kai Ma, Zheng Zhu, Zhen-Bo Cao. Originally published in JMIR mHealth and uHealth (http://mhealth.jmir.org), 07.01.2021.)

Objectives: Objectively measured sedentary behavior (SB) on weekdays and weekends has been mainly assessed in white-collar workers, while data in blue-collar workers are sparse. Therefore, this study presented the difference in accelerometer-measured SB levels between weekdays and weekends, stratified by white- and blue-collar occupations., Methods: This study was a sub-analysis of accelerometer data from 73 workers (31 blue-collar and 42 white-collar) at a Japanese manufacturing plant. SB was defined as ≤1.5 metabolic equivalents estimated using an accelerometer, and compared between weekdays and weekends by using mixed models adjusted for confounders. The proportion of workers who sat for ≤8 h/day on weekdays and weekends were compared using McNemar's test., Results: In white-collar workers, SB time on weekdays was significantly longer than that on weekends (598 vs 479 min/day, P < .001). In blue-collar workers, there was no significant difference in SB time between weekdays and weekends (462 vs 485 min/day, P = .43). The proportion of workers who achieved the recommended SB levels (≤8 h) was only 4.8% for white-collar workers on weekdays and 54.8% on weekends (P = .04), while that of blue-collar workers was 45.2% and 58.1% respectively (P > .99)., Conclusions: White-collar workers were exposed to significantly longer SB time on weekdays than on weekends, which was not the case in blue-collar workers. It may be rather challenging for white-collar workers to limit their SB time to the level recommended by the latest guidelines for better health, especially on weekdays., (© 2021 The Authors. Journal of Occupational Health published by John Wiley & Sons Australia, Ltd on behalf of The Japan Society for Occupational Health.)

Device-based assessments are frequently used to measure physical activity (PA) but contextual measures are often lacking. There is a need for new methods, and one under-explored option is the use of wearable cameras. This study tested the use of wearable cameras in PA measurement by comparing intensity classifications from accelerometers with wearable camera data. Seventy-eight 18-30-year-olds wore an Actigraph GT9X link accelerometer and Autographer wearable camera for three consecutive days. An image coding schedule was designed to assess activity categories and activity sub-categories defined by the 2011 Compendium of Physical Activities (Compendium). Accelerometer hourly detailed files processed using the Montoye (2020) cut-points were linked to camera data using date and time stamps. Agreement was examined using equivalence testing, intraclass correlation coefficient (ICC) and Spearman's correlation coefficient (rho). Fifty-three participants contributing 636 person-hours were included. Reliability was moderate to good for sedentary behavior (rho = 0.77), light intensity activities (rho = 0.59) and moderate-to-vigorous physical activity (MVPA) (rho = 0.51). The estimates of sedentary behavior, light activity and MVPA from the two methods were similar, but not equivalent. Wearable cameras are a potential complementary tool for PA measurement, but practical challenges and limitations exist. While wearable cameras may not be feasible for use in large scale studies, they may be feasible in small scale studies where context is important.

To examine the longitudinal associations of objectively measured physical activity and modified organized sport participation with executive functions and psychological health in preschoolers. One hundred and eighty-five preschool children, mean age 4.2 ± 7.68; (years:months), 34% girls were followed for one year. Physical activity was measured using accelerometery, examining light, moderate, vigorous, moderate-to-vigorous, and total physical activity. Parents reported children's participation in modified organized sport. Direct assessment of children's executive functions (working memory, inhibition and shifting) and educator-reported psychosocial difficulties were also collected. Associations were examined using linear regression adjusting for covariates, baseline developmental outcomes and preschool clustering. Vigorous physical activity at baseline was positively associated with children's shifting performance (b = 0.245; 95% CI: 0.006, 0.485, p =.045) at follow-up, while the association for moderate-to-vigorous physical activity approached significance (b = 0.119; 95% CI: -0.001, 0.239, p =.051). Children not participating in modified organized sport at baseline demonstrated better inhibition scores 12-months later compared to sports participants (Mdiff 0.06; CI: 0.00, 0.13, p =.046). Increasing time spent in higher intensity physical activity among preschool children may be a viable target for supporting their later cognitive development, although there was no clear benefit of early participation in modified organized sport.

Farmworkers are exposed to physical risk factors including repetitive motions. Existing ergonomic assessment methods are primarily laboratory-based and, thus, inappropriate for use in the field. This study presents an approach to characterize the repetitive motions of the upper arms based on direct measurement using accelerometers. Repetition rates were derived from upper arm inclination data and with video recordings in the field. This method was used to investigate whether harvesting with mobile platforms (teams harvesting apples from the platform and the ground) increased the farmworkers' exposure to upper arm repetitive motions compared to traditional harvesting using ladders. The ladder workers had higher repetitive motions (13.7 cycles per minute) compared to the platform and ground workers (11.7 and 12.2 cycles per minutes). The higher repetitions in the ladder workers were likely due to their ability to work independently and the additional arm movements associated with ladder climbing and walking., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Despite recent popularity of wrist-worn accelerometers for assessing free-living physical behaviours, there is a lack of user-friendly methods to characterize physical activity from a wrist-worn ActiGraph accelerometer. Participants in this study completed a laboratory protocol and/or 3-8 hours of directly observed free-living (criterion measure of activity intensity) while wearing ActiGraph GT9X Link accelerometers on the right hip and non-dominant wrist. All laboratory data (n = 36) and 11 participants' free-living data were used to develop vector magnitude count cut-points (counts/min) for activity intensity for the wrist-worn accelerometer, and 12 participants' free-living data were used to cross-validate cut-point accuracy. The cut-points were: <2,860 counts/min (sedentary); 2,860-3,940 counts/min (light); and ≥3,941counts/min (moderate-to-vigorous (MVPA)). These cut-points had an accuracy of 70.8% for assessing free-living activity intensity, whereas Sasaki/Freedson cut-points for the hip accelerometer had an accuracy of 77.1%, and Hildebrand Euclidean Norm Minus One (ENMO) cut-points for the wrist accelerometer had an accuracy of 75.2%. While accuracy was higher for a hip-worn accelerometer and for ENMO wrist cut-points, the high wear compliance of wrist accelerometers shown in past work and the ease of use of count-based analysis methods may justify use of these developed cut-points until more accurate, equally usable methods can be developed.

Purpose: Survivors of breast cancer (BC) on the non-dominant side have more persistent deficits than those with cancer on the dominant limb. What is not known is whether those with BC use their involved upper limbs more, less, or at the same level as women without BC. Accelerometer use offers a quantifiable method to measure activity levels of upper limbs. The purpose of this study was to quantify the activity levels of the non-dominant involved limb among survivors of BC and compare these values to their dominant limb, as well as the non-dominant limb of a control group., Methods: Participants (n = 30) were women with unilateral BC on the non-dominant limb, diagnosed between 6 and 24 months prior to data collection, and a matched healthy group of women as controls. Participants completed the following questionnaires: medical and demographics, Brief Fatigue Inventory, Brief Pain Inventory - Short form, Disabilities of the Arm, Shoulder and Hand (DASH), and Beck Depression Index. Participants wore an accelerometer on each wrist during waking hours for 7 days. Arm activity was measured using vector magnitude activity counts extracted from the accelerometers., Results: There were no significant differences in total vector magnitude activity counts between groups for either limb. Within group dominant to non-dominant comparison was significantly different (p ≤ 0.001). No significant difference in pain was present but significant differences for fatigue (p = 0.002), depression (p = 0.004), and DASH scores (p = 0.035) were present., Conclusions: Women with non-dominant BC use their involved limb similar to healthy controls but less than their dominant limb.

Environmental and logistical difficulties associated with obtaining whole-body vibration measurements from mobile equipment during operation in underground coal mines have hampered attempts to assess the potential vibration exposures associated with the use of such equipment. An alternative measurement technique was used to gather data from mobile equipment during normal operation at three low-methane coal mines and to estimate the possible magnitude of benefit of three control measures. 188 long duration measurements were obtained from shuttle cars (N = 142, median measurement duration = 3.2 h); personnel transport (N = 24, median measurement duration = 2.4 h); and materials transport vehicles (N = 22, median measurement duration = 1.8 h). Whole-body vibration amplitudes either within or exceeding the ISO health guidance caution zone were consistently measured. In particular, shuttle cars demonstrated whole-body vibration amplitudes which frequently exceeded the health guidance caution zone. The potential effects of roadway maintenance, decreased vehicle speed, and shuttle car seat replacement were found to be practically meaningful., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This study compared farmworkers' exposure to non-neutral postures using a new mobile platform apple harvesting method and the traditional method using ladders. Twenty-four workers were recruited and assigned into three groups: ladder workers (n = 8) picking apples from full trees using a ladder, mobile platform workers (n = 8) picking apples from upper part of the trees while standing on a moving platform, and ground-based mobile platform workers (n = 8) picking apples from lower part of the trees which the mobile platform workers left out. Upper arm and back inclinations were continuously monitored during harvesting using tri-axial accelerometers over full work shifts (~8 h). Upper arm posture was characterized as the percentage of time that upper arm flexion and abduction exceeded 30°, 60°, and 90°. Back posture was characterized as the percentage of time that torso angles (sagittal flexion or lateral bending) exceeded 10°, 20°, and 30°. The 10th, 50th, and 90th postural percentiles were also calculated. The platform workers had lower exposures to upper arm flexion and abduction than the ground and ladder workers. There were no differences in torso angles between the ladder and mobile platform workers; however, the ground workers were exposed to more and greater percentages of time in torso flexions., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives The potential effects of physical activity and sedentary time on children's increasing neck and shoulder pain are unclear. The aim of this cross-sectional study was to evaluate the associations between objectively measured physical activity or sedentary time and neck and shoulder pain in children. Methods Children (n=905; 10-15 years old) filled in an electronic questionnaire during school hours on the frequency of their neck and shoulder pain. Daytime moderate to vigorous physical activity and sedentary time were measured objectively with an ActiGraph accelerometer. A multinomial logistic regression was applied to study the associations. The results were adjusted for age, gender, body mass index and bedtime. Results Neck and shoulder pain experienced at least once a week was reported by 26.1% of children. A higher proportion of boys (45.9%) than girls (24.2%) achieved at least 60 min of moderate to vigorous physical activity/day (p<0.001). Girls were more sedentary than boys (sedentary time 66.4 vs. 63.1%) (p<0.001). Higher moderate to vigorous physical activity time was associated with a lower probability of experiencing neck and shoulder pain among boys, but not among girls. No association was found between sedentary time and neck and shoulder pain. Conclusions A quarter of the girls and boys reported frequent neck and shoulder pain. Boys achieved more moderate to vigorous physical activity than girls and higher moderate to vigorous physical activity was associated with a lower probability of having neck and shoulder pain, but only in boys. Neck and shoulder pain is the most common musculoskeletal pain and its prevalence is increasing. Preventing childhood pain is important, as neck and shoulder pain causes restrictions in daily living and is persistent to adulthood. Our study showed, that boys with more moderate to vigorous physical activity, had less weekly neck and shoulder pain symptoms. The present results are an addition to the list of benefits of physical activity and are valuable to, for example, healthcare personnel and teachers, who guide and teach children and adolescents. Families can benefit from new knowledge when considering supportive parenting activities. Municipalities can use the new information to design services for children or families.

Objective: To explore associations between physical activity and peak oxygen uptake (VO2peak), age, sex, and Hoffer classification in young wheelchair-users with spina bifida., Design: Exploratory study., Subjects: Fifty-three dutch children (age 5-19 years) with spina bifida who use a manual wheelchair., Methods: For the dependent variable physical activity, data from 2 physical activity monitors were analysed: VitaMove data for 34 participants and Actiheart data for 36 participants. Time sedentary, time physically active, and time in moderate to vigorous physical activity were analysed. The Wheelchair Shuttle Test was used to measure VO2peak. Univariate and multivariate regression analyses were performed. Independent variables were VO2peak, age, sex, and Hoffer classification., Results: Time sedentary and time physically active during a school day were influenced by age (β=0.326/β=-0.320) and Hoffer classification (β=0.409/β=-0.534) and during a weekend day by Hoffer classification (β=0.617/β=-0.428). Time in moderate to vigorous physical activity was influenced by Hoffer classification (β=-0.527) during a school day and by age (β=-0.600) during a weekend day., Conclusion: Older age and the inability to walk negatively influence physical activity. Sex and VO2peak were not associated with physical activity. These results imply that increasing cardiorespiratory fitness alone will not improve physical activity in young wheelchair-users with spina bifida.

By exploring multiple characteristics of physical activity and sedentary behavior (SB), different physical activity profiles could be obtained, which may be beneficial for health and targeted physical activity interventions. The aim of this study was to identify distinct physical activity profiles based on accelerometer-derived activity characteristics and to determine whether these profiles are associated with all-cause mortality. Eight hundred fifty-one participants (56% women, mean age: 53 years) provided objectively assessed physical activity data using an ActiGraph accelerometer and were followed for 15 years. Physical activity profiles were determined using latent profile analyses of 14 derived activity variables, resulting in that three profiles were identified: "Low Active" (n = 147), "Average Active" (n = 397), and "High Active" (n = 307). "Low Active" was characterized by participants with low absolute, relative, and limited variation of time spent in physical activity, and high time spent in SB. "Average Active" had the most balanced movement behavior with values close to the mean for all activity variables. "High Active" was characterized by participants with high absolute, relative, and great variation of time spent in physical activity. Overall, a potentially non-linear pattern between multiple activity variables and all-cause mortality was found as "Low Active" was significantly (P < .05) positively associated with all-cause mortality, and no difference in mortality risk was found between "High Active" and "Average Active." Our data suggest that day-to-day variation in SB is not associated with all-cause mortality. The important message is to keep the overall time spent in SB low and replace this behavior with physical activity., (© 2020 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Perceived racial discrimination is linked to unhealthy behaviors and stress-related morbidities. A compelling body of research indicates that perceived racial discrimination may contribute to health disparities among African Americans (AAs). The purposes of this study were to describe the study protocol including data collection procedures and study measures and to evaluate the feasibility and acceptability of intensive biobehavioral data collection using ecological momentary assessment (EMA), salivary biomarkers, and accelerometers over 7 days among middle-aged AAs with a goal of understanding the relationships between perceived racial discrimination and biobehavioral responses to stress. Twelve AA men and women participated in the feasibility/acceptability study. They completed surveys, anthropometrics, and received in-person training in EMA and saliva sample collection at baseline. Participants were asked to respond to the random prompt text message-based EMA five times a day, wear an accelerometer daily for 7 days, and to self-collect saliva samples four times a day for 4 consecutive days. The EMA surveys included perceived racial discrimination, affective states, lifestyle behaviors, and social and physical contexts. The mean EMA response rate was 82.8%. All participants collected saliva samples four times a day for 4 consecutive days. About 83% of participants wore the accelerometer on the hip 6 out of 7 days. Despite the perception that the intensive nature of assessments would result in high participant burden, the acceptability of the study procedures was uniformly favorable., (© 2020 Wiley Periodicals LLC.)

Objective: The degree of sedation or agitation in critically ill patients is typically assessed with the Richmond Agitation and Sedation Scale (RASS). However, this approach is intermittent and subject to unrecognised variation between assessments. High frequency accelerometry may assist in achieving a quantitative and continuous assessment of sedation while heralding imminent agitation., Design: We undertook a prospective, observational pilot study., Setting: An adult tertiary intensive care unit in Melbourne, Australia., Participants: 20 patients with an admission diagnosis of trauma., Main Outcome Measures: Accelerometers were applied to patients' wrists and used to continuously record patient movement. Video data of patient behaviour were simultaneously collected, and observers blinded to accelerometry data were adjudicated the RASS score every 30 seconds. Exploratory analyses were undertaken., Results: Patients were enrolled for a median duration of 9.7 hours (interquartile range [IQR], 0-22.8) and a total of 160 hours. These patients had a median RASS score of 0 (IQR, -4 to 0). A 2-minute moving window of amplitude variance was seen to reflect contemporaneous fluctuations in motor activity and was proportional to the RASS score. Furthermore, the moving window of amplitude variance was observed to spike immediately before ≥ 2 point increases in the RASS score., Conclusions: We describe a novel approach to the analysis of wrist accelerometry data in critically ill patients. This technique not only appears to provide novel and continuous information about the depth of sedation or degree of agitation, it is also notable in its aptitude to anticipate impending transitions to higher RASS values.

Built environments have been cited as important facilitators of activity and research using geographic information systems (GIS) has emerged as a novel approach in exploring environmental determinants. The Active Children Through Individual Vouchers Evaluation Project used GIS to conduct a cross-sectional analysis of how teenager's (aged 13-14) environments impacted on their amount of activity and influences fitness. The ACTIVE Project recruited 270 participants aged 13-14 (year 9) from 7 secondary schools in south Wales, UK. Demographic data and objective measures of accelerometery and fitness were collected from each participant between September and December 2016. Objective data was mapped in a GIS alongside datasets relating to activity provision, active travel routes, public transport stops, main roads and natural resources. This study shows that fitness and physical activity are not correlated. Teenagers who had higher levels of activity also had higher levels of sedentary time/inactivity. Teenagers showed higher amounts of moderate-to-vigorous physical activity if their homes were closer to public transport. However, they were also more active if their schools were further away from public transport and natural resources. Teenagers were fitter if schools were closer to natural resources. Sedentary behaviour, fitness and activity do not cluster in the same teenagers. Policymakers/planning committees need to consider this when designing teenage friendly environments. Access to public transport, active travel, green space and activities that teenagers want, and need could make a significant difference to teenage health., Competing Interests: All authors declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

Background: Levels of physical activity change throughout the year. However, little is known to what extent activity levels can vary, based on accelerometer determined sedentary and physically-active time. The aim of this longitudinal study was to examine older adults' activity changes from a non-snowfall season to a subsequent snowfall season, with consideration of the co-dependence of domains of time use., Methods: Participants were 355 older Japanese adults (53.1% women, aged 65-84 years) living in a rural area of heavy snowfall who had valid accelerometer (Active style Pro HJA-750C) data during non-snowfall and snowfall seasons. Activity was classified as sedentary behavior (SB), light-intensity PA (LPA), and moderate-to-vigorous PA (MVPA). Compositional changes from the non-snowfall to the snowfall season were analyzed using Aitchison's perturbation method. The ratios of each component in the composition, such as [SBsnow/SBnon-snow, LPAsnow/LPAnon-snow, MVPAsnow/MVPAnon-snow] for seasonal changes, were calculated and were then divided by the sum of these ratios., Results: In men, the percentages of time spent in each activity during the non-snowfall/snowfall seasons were 53.9/64.6 for SB; 40.8/31.6 for LPA; and 5.3/3.8 for MVPA; these corresponded to mean seasonal compositional changes (∆SB, ∆LPA, ∆MVPA) of 0.445, 0.287, and 0.268 respectively. In women, the percentages of time spent in each activity during the non-snowfall/snowfall seasons were 47.9/55.5 for SB; 47.9/41.0 for LPA; and 4.2/3.5 for MVPA; these corresponded to mean seasonal compositional changes (∆SB, ∆LPA, ∆MVPA) of 0.409, 0.302, and 0.289 respectively. The degree of seasonal change was greatest in men., Conclusions: In older adults, activity behaviors were changed unfavorably during snowfall season, particularly so for men. The degree of seasonal change was greatest for SB. Development of strategies to keep rural older adults active during the snowfall season may be needed for maintaining a consistently-active lifestyle for their health.

Background: When tested in a controlled clinic environment, individuals with neuromuscular-related symptoms may complete motor tasks within normal predicted ranges. However, measuring activity at home may better reflect typical motor performance. The accuracy of accelerometry measurements in individuals with congenital muscular dystrophy (CMD) is unknown. We aimed to compare accelerometry and manual step counts and assess free-living physical activity intensity in individuals with CMD using accelerometry., Methods: Ambulatory pediatric CMD participants (n = 9) performed the 6-minute walk test in clinic while wearing ActiGraph GT3X accelerometer devices. During the test, manual step counting was conducted to assess concurrent validity of the ActiGraph step count in this population using Bland-Altman analysis. In addition, activity intensity of 6 pediatric CMD participants was monitored at home with accelerometer devices for an average of 7 days. Cut-point values previously validated for neuromuscular disorders were used for data analysis., Results: Bland-Altman and intraclass correlation analyses showed no concurrent validity between manual and ActiGraph-recorded step counts. Fewer steps were recorded by ActiGraph step counts compared with manual step counts (411 ± 74 vs 699 ± 43, respectively; P = .004). Although improved, results were in the same direction with the application of low-frequency extension filters (587 ± 40 vs 699 ± 43, P = .03). ActiGraph step-count data did not correlate with manual step count (Spearman ρ = 0.32, P = .41; with low-frequency extension: Spearman ρ = 0.45, P = .22). Seven-day physical activity monitoring showed that participants spent more than 80% of their time in the sedentary activity level., Conclusions: In a controlled clinic setting, step count was significantly lower by ActiGraph GT3X than by manual step counting, possibly because of the abnormal gait in this population. Additional studies using triaxial assessment are needed to validate accelerometry measurement of activity intensity in individuals with CMD. Accelerometry outcomes may provide valuable measures and complement the 6-minute walk test in the assessment of treatment efficacy in CMD.

Background: The current international physical activity guidelines for health recommend children to engage in at least 60 minutes of moderate-to-vigorous physical activity (MVPA) daily. Yet, accurate prevalence estimates of physical activity levels of children are unavailable in many African countries due to the dearth of accelerometer-measured physical activity data. The aim of this study was to describe the prevalence and examine the socio-demographic correlates of accelerometer-measured physical activity among school-going children in Kampala city, Uganda., Methods: A cross-sectional study design was used to recruit a sample of 10-12 years old school-going children (n = 256) from 7 primary schools (3 public schools and 4 private schools) in Kampala city, Uganda. Sedentary time, light-intensity physical activity (LPA), moderate-intensity physical activity (MPA) and vigorous-intensity physical activity (VPA) were measured by accelerometers (ActiGraph GT3X+ [Pensacola, Florida, USA]) over a seven-day period. Socio-demographic factors were assessed by a parent/guardian questionnaire. Weight status was generated from objectively measured height and weight and computed as body mass index (BMI). Multi-level logistic regressions identified socio-demographic factors that were associated with meeting physical activity guidelines., Results: Children's sedentary time was 9.8±2.1 hours/day and MVPA was 56±25.7 minutes/day. Only 36.3% of the children (38.9% boys, 34.3% girls) met the physical activity guidelines. Boys, thin/normal weight and public school children had significantly higher mean daily MVPA levels. Socio-demographic factors associated with odds of meeting physical activity guidelines were younger age (OR = 0.68; 95% CI = 0.55-0.84), thin/normal weight status (OR = 4.08; 95% CI = 1.42-11.76), and socioeconomic status (SES) indicators such as lower maternal level of education (OR = 2.43; 95% CI = 1.84-3.21) and no family car (OR = 0.31; 95% CI = 0.17-0.55)., Conclusion: Children spent a substantial amount of time sedentary and in LPA and less time in MVPA. Few children met the physical activity guidelines. Lower weight status, lower maternal education level and no family car were associated with meeting physical activity guidelines. Effective interventions and policies to increase physical activity among school-going children in Kampala, are urgently needed., Competing Interests: The authors have declared that no competing interest exists.

Objectives: To examine the relationship between time spent in light physical activity (LPA) and in moderate to vigorous physical activity (MVPA) and the pattern of accumulation on the risk for major mobility disability (MMD) in a large multicenter study of physical activity (PA) and aging, the Lifestyle Interventions and Independence for Elders (LIFE) study., Design: Data were collected from individuals randomized to a PA intervention as part of the LIFE study, an eight-center single-blind randomized clinical trial conducted between February 2010 and December 2013., Setting: Lifestyle Interventions and Independence for Elders Study PARTICIPANTS: Older adult participants (78.4 years; N = 507) at risk for MMD., Intervention: All older adults included in these analyses were randomized to a structured PA intervention that included two center-based plus three to four home-based exercise sessions per week with a primary goal of walking for 150 minutes weekly. Participants attended the intervention for 2.5 years on average., Measurements: MMD was defined as the inability to complete a 400-m walk within 15 minutes and without assistance. Physical function was assessed via the Short Physical Performance Battery (SPPB). Actigraph accelerometers were used to quantify amount and variability in LPA and MVPA., Results: In an adjusted Cox proportional hazards regression, we identified a significant interaction (P = .017) between SPPB score and LPA amount and variability such that more LPA was associated with a reduced risk for MMD among those with higher initial function, as was lower variability (eg, via distributing LPA across the day). The SPPB × MVPA interaction was significant (P = .04), such that more MVPA was associated with lower MMD risk among those with lower function. Finally, greater MVPA variability was associated with lower risk for MMD., Conclusion: A prescription of PA for older adults should account for key factors such as physical function and emphasize both amount and pattern of accumulation of PA from across the intensity continuum. J Am Geriatr Soc 68:1476-1483, 2020., (© 2020 The American Geriatrics Society.)

Purpose: Stroke-related changes in foot structure and function affect balance and mobility and quantifying foot function following stroke could offer clinically useful information to inform rehabilitation. The aim of this work was to explore the feasibility of undertaking plantar pressure assessment during barefoot walking in people with stroke, and evaluate the repeatability of the assessment protocol and regional footprint analysis as a measure of dynamic foot characteristics., Materials & Methods: Plantar pressure analysis was undertaken using a pressure platform (Tekscan HR Mat) on two test sessions, approximately two weeks apart (mean = 15.64 ± 11.64 days). Peak plantar pressure (kPa) and contact area (cm 2 ) for foot regions were extracted and repeatability analysis undertaken. Descriptive evaluation of field notes and experiences of the participants was undertaken to inform the feasibility of the data collection protocol., Results: Twenty-one participants (61.8 ± 9.2 years; 11 male, 10 female; 8 right-sided, 13 left-sided stroke) were recruited and 18 returned for retesting. Full data capture was achieved from 14 participants. Peak pressure and contact area demonstrated moderate to good repeatability for at the toes (ICC 0.76 and 0.58 respectively) and good to excellent repeatability for the other foot regions (ICC ≥ 0.82)., Conclusion: The protocol adopted in this study was feasible and yielded good to excellent repeatability for the foot regions, except the toes. The challenges with data collection in our study cohort could help inform future studies adopting similar protocols. This work also has relevance for use of pressure technology in clinical practice for assessing and monitoring foot function following stroke.

Objective: The objective of this study was to evaluate the responsiveness of the single item measure (SIM) to detect change in PA when compared to hip-worn accelerometry. A secondary aim was to provide further data on validity of the measure at a single time point., Methods: Validity of the SIM to determine the number of days of ≥30 minutes of accelerometer-derived moderate-to-vigorous physical activity (MVPA) was assessed in 120 participants (78% female, 19% male, 3% other; age: 46 ± 11 years). Analysis of change was based on change in the number of days that participants completed ≥30 minutes of MVPA determined by the SIM and accelerometry over two 7-day periods in 90 participants (age: 47±11 years). Accelerometer data were analysed as total minutes of MVPA per day (MVPA-total) and as sustained bouts of 10 minutes or more of MVPA (MVPA-bouts). Validity of the SIM to detect change in MVPA, using accelerometer data as the reference measurement, was examined through Spearman's correlation and agreement in classification of change between SIM and accelerometry. Responsiveness to change was assessed by standardised response means and Cohen's d., Results: Standardised response means for PA change were moderate for the SIM (0.77), MVPA-total (0.57) and MVPA-bouts (0.79). The correlation for change in number of days ≥30 minutes MVPA between the SIM and accelerometry were small to moderate (MVPA-total: r = 0.36 and MVP-bouts: r = 0.40). The SIM displayed moderate accuracy (60%-63%), using accelerometer data as the reference measurement, in detecting increases in days ≥30 minutes of MVPA., Conclusion: The SIM is a potentially useful assessment tool for evaluating change in MVPA, particularly when device-based measures or longer self-report measures are not feasible., Competing Interests: The authors have read the journal's policies and the authors of this article have the following competing interests: One of the co-authors, AW, is a staff member of the funding body (VicHealth), and as such the funder had a role in the preparation of the manuscript. There are no patents, products in development or marketed products to declare.This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: The impact of light-intensity physical activity (LPA) in preventing cancer mortality has been questioned. To address this concern, the present meta-analysis aimed to quantify the association between objectively-measured LPA and risk of cancer mortality., Methods: We conducted a systematic literature search in PubMed and Scopus to January 2020. Prospective cohort studies reporting the association between objectively-measured LPA using activity monitors (e.g., accelerometers) and risk of cancer mortality in the general population were included. The summary hazard ratios (HR) per 30 min/day of LPA and 95% confidence intervals (CI) were obtained using a random-effects model. Dose-response analysis was used to plot their relationship., Results: Five prospective cohort studies were included, in which the definition of LPA based on accelerometer readings was mainly set within 100 to 2,100 counts/min. The summary HR for cancer mortality per 30 min/day of LPA was 0.86 (95% CI, 0.79-0.95; I 2 < 1%), and the association between LPA and risk reduction in cancer mortality was linearly shaped ( P nonlinearity = 0.72). LPA exhibited a comparable magnitude of risk reduction in cancer mortality of moderate-to-vigorous physical activity regardless of equal time-length (0.87 per 30 min/day vs. 0.94 per 30 min/day, P interaction = 0.46) or equal amount (0.74 vs. 0.94 per 150 metabolic equivalents-min/day, P interaction = 0.11). Furthermore, replacing sedentary time by LPA of 30 min/day decreased the risk of cancer mortality by 9%., Conclusions: Objectively-measured LPA conferred benefits in decreasing the risk of cancer mortality., Impact: LPA should be considered in physical activity guidelines to decrease the risk of cancer mortality., (©2020 American Association for Cancer Research.)

Introduction: Sensor-based assessment of challenging behaviors in dementia may be useful to support caregivers. Here, we investigated accelerometry as tool for identification and prediction of challenging behaviors., Methods: We set up a complex data recording study in two nursing homes with 17 persons in advanced stages of dementia. Study included four-week observation of behaviors. In parallel, subjects wore sensors 24 h/7 d. Participants underwent neuropsychological assessment including MiniMental State Examination and Cohen-Mansfield Agitation Inventory., Results: We calculated the accelerometric motion score (AMS) from accelerometers. The AMS was associated with several types of agitated behaviors and could predict subject's Cohen-Mansfield Agitation Inventory values. Beyond the mechanistic association between AMS and behavior on the group level, the AMS provided an added value for prediction of behaviors on an individual level., Discussion: We confirm that accelerometry can provide relevant information about challenging behaviors. We extended previous studies by differentiating various types of agitated behaviors and applying long-term measurements in a real-world setting., (© 2019 The Authors. Alzheimer's & Dementia published by Wiley Periodicals, Inc. on behalf of Alzheimer's Association.)

Background: Identifying modifiable risk factors is essential to reduce the prevalence adolescent depression. Self-report data suggest that physical activity and sedentary behaviour might be associated with depressive symptoms in adolescents. We examined associations between depressive symptoms and objectively measured physical activity and sedentary behaviour in adolescents., Methods: From a population-based cohort of adolescents whose mothers were invited to participate in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, we included participants with at least one accelerometer recording and a Clinical Interview Schedule-Revised (CIS-R) depression score at age 17·8 years (reported as age 18 years hereafter). Amounts of time spent in sedentary behaviour and physical activity (light or moderate-to-vigorous) were measured with accelerometers at around 12 years, 14 years, and 16 years of age. Total physical activity was also recorded as count per minute (CPM), with raw accelerometer counts averaged over 60 s epochs. Associations between the physical activity and sedentary behaviour variables and depression (CIS-R) scores at age 18 years were analysed with regression and group-based trajectory modelling., Findings: 4257 adolescents from the 14 901 enrolled in the ALSPAC study had a CIS-R depression score at age 18 years. Longitudinal analyses included 2486 participants at age 12 years, 1938 at age 14 years, and 1220 at age 16 years. Total follow-up time was 6 years. Total physical activity decreased between 12 years and 16 years of age, driven by decreasing durations of light activity (mean 325·66 min/day [SD 58·09] at 12 years; 244·94 min/day [55·08] at 16 years) and increasing sedentary behaviour (430·99 min/day [65·80]; 523·02 min/day [65·25]). Higher depression scores at 18 years were associated with a 60 min/day increase in sedentary behaviour at 12 years (incidence rate ratio [IRR] 1·111 [95% CI 1·051-1·176]), 14 years (1·080 [1·012-1·152]), and 16 years of age (1·107 [1·015-1·208]). Depression scores at 18 years were lower for every additional 60 min/day of light activity at 12 years (0·904 [0·850-0·961]), 14 years (0·922 [0·857-0·992]), and 16 years of age (0·889 [0·809-0·974]). Group-based trajectory modelling across 12-16 years of age identified three latent subgroups of sedentary behaviour and activity levels. Depression scores were higher in those with persistently high (IRR 1·282 [95% CI 1·061-1·548]) and persistently average (1·249 [1·078-1·446]) sedentary behaviour compared with those with persistently low sedentary behaviour, and were lower in those with persistently high levels of light activity (0·804 [0·652-0·990]) compared with those with persistently low levels of light activity. Moderate-to-vigorous physical activity (per 15 min/day increase) at age 12 years (0·910 [0·857-0·966]) and total physical activity (per 100 CPM increase) at ages 12 years (0·941 [0·910-0·972]) and 14 years (0·965 [0·932-0·999]), were negatively associated with depressive symptoms., Interpretation: Sedentary behaviour displaces light activity throughout adolescence, and is associated with a greater risk of depressive symptoms at 18 years of age. Increasing light activity and decreasing sedentary behaviour during adolescence could be an important target for public health interventions aimed at reducing the prevalence of depression., Funding: Details of funding are provided in the Acknowledgments., (Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Objective: To describe the sleep time window (STW), total sleep time (TST), and sleep percent [SP = (TST/STW) × 100] by accelerometry in a population-based young adult cohort in Brazil., Methods: Cross-sectional analysis with a 22-year sample (N = 2462). Sleep variables were measured using an accelerometer. The devices were worn on the non-dominant wrist for approximately seven days. A raw data analysis using the GGIR package was performed. The following sleep variables were extracted: TST, STW, and SP. Linear regression was used to adjust averages. All analyses were stratified according to sex. A comparison between weekday and weekend averages was also conducted., Results: The means of TST, STW, and SP for men were 5.9 h, 7.1 h, and 83.1%, respectively. For women, the means of TST, STW, and SP were 6.4 h, 7.6 h, and 84.6%, respectively. Women presented a higher means of all outcomes compared to men (p < 0.001). After adjusting for both sexes, white skin color and not working or studying were associated with higher TST. Individuals not working or studying presented higher means of STW and lower sleep SP. Women with children who were less than two years of age presented lower values of three evaluated outcomes. Regarding behavior and health condition variables, obesity was associated with lower STW only for men. Physical activity was associated with higher SP and risk drinking with lower TST and STW only for women., Conclusion: Differences between sexes were observed in TST, STW, and SP. In all outcomes women presented a higher means. Socioeconomic variables were associated with both sexes, but having children and behavior/health conditions differed between sexes., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Accelerometer cut points are an important consideration for distinguishing the intensity of activity into categories such as moderate and vigorous. It is well-established in the literature that these cut points depend on a variety of factors, including age group, device, and wear location. The Actigraph GT9X is a newer model accelerometer that is used for physical activity research, but existing cut points for this device are limited since it is a newer device. Furthermore, there is not existing data on cut points for the GT9X at the ankle or foot locations, which offers some potential benefit for activities that do not involve arm and/or core motion. A total of N = 44 adults completed a four-stage treadmill protocol while wearing Actigraph GT9X sensors at four different locations: foot, ankle, wrist, and hip. Metabolic Equivalent of Task (MET) levels assessed by indirect calorimetry along with Receiver Operating Characteristic (ROC) curves were used to establish cut points for moderate and vigorous intensity for each wear location of the GT9X. Area under the ROC curves indicated high discrimination accuracy for each case.

Background: Parents are central to healthy development in early childhood. Study objectives were to examine the associations between parent and child sedentary behaviour and physical activity in a large representative sample of Canadian 3-5-year-olds, and to determine if associations differed between sons and daughters and mothers and fathers., Data and Methods: Participants were 1,116 children aged 3-5 years and one of their biological parents from cycles 2-5 (2009-2017) of the repeated cross-sectional Canadian Health Measures Survey. Sedentary time, light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) were objectively-measured in both parents and children with Actical accelerometers. Average minutes/day for all valid days, valid weekdays, and valid weekend days (n=935) were calculated. Screen time of both parents and children was parent-reported, and average hours/day were calculated. Pearson correlations and linear regression models with interaction terms were conducted., Results: In the overall sample, all of the parental physical activity and sedentary behaviours were significantly correlated with children's behaviours (r=0.08-0.20). No significant parental or child sex interactions were observed in linear regression models so models were not stratified by parent or child sex. Significant associations with small effect sizes were observed between all of the parental behaviours and children's behaviours. For accelerometer data this was consistent for total days, weekdays, and weekend days., Discussion: Parental sedentary behaviour and physical activity may be intervention targets in early childhood. This appears consistent regardless of the sex of the parent or child. Given the small effect sizes observed, additional intervention targets should also be considered.

Background: Lumbar spinal disease causes disabilities in performing daily activities. Operative treatments are aimed at pain relief and rapid return to routine activity. Patient-based outcome measures are used to evaluate pathologies and therapeutic effects associated with lumbar spinal disease. Nevertheless, it remains unknown as to how much such treatment improves activity levels. The purpose of the current study was to measure changes in activity levels before and after lumbar spinal surgery using a wearable activity tracker and to analyze the differences between results and patient-based outcomes., Methods: Sixty patients who underwent lumbar surgery were studied. The physical activity of participants was objectively evaluated using a wearable Micro-Motion logger system (Actigraph). We measured the amount of activity before and at 1, 3, 6, and 12 months after the surgery to evaluate postoperative changes. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, Oswestry Disability Index, Roland-Morris Disability Questionnaire and visual analog scale were used to assess patient-based outcomes of pain and activities of daily living-related scores; we analyzed the relationships between scores and actual activity levels., Results: The amount of actual activity decreased significantly 1 month after the surgery compared to that during the preoperative period, which then improved after 3 months postoperatively (p < 0.01). Furthermore, there was a significant improvement 6 months after the surgery compared to that during the preoperative period (p < 0.05). The changes in activity for each period were strongly correlated, regardless of the period. In contrast, a significant improvement was observed at 1 month after the surgery in almost all items of the patient-based questionnaires (p < 0.05)., Conclusions: The objective activity tracker demonstrated that lumbar surgery results in the amount of activity decreasing 1 month just after surgery followed by gradual postoperative recovery within 3 months. By contrast, patient-based outcomes showed improvement in 1 month that was significantly different from the change in actual activity, indicating a gap between patient-oriented clinical scores and their actual activities.