The validation of a novel activity monitor in the measurement of posture and motion during everyday activities

Association of 12-Year Trajectories of Sitting Time With Frailty in Middle-Aged Women

Prolonged sitting time is associated with several health outcomes; limited evidence indicates associations with frailty. Our aims in this study were to identify patterns of sitting time over 12 years in middle-aged (ages 50-55 years) women and examine associations of these patterns with frailty in older age. We examined 5,462 women born in 1946-1951 from the Australian Longitudinal Study on Women's Health who provided information on sociodemographic attributes, daily sitting time, and frailty in 2001 and then again every 3 years until 2013. Frailty was assessed using the FRAIL (fatigue, resistance, ambulation, illness, loss of weight) scale (0 = healthy; 1-2 = prefrail; 3-5 = frail), and group-based trajectory analyses identified trajectories of sitting time. We identified 5 sitting-time trajectories: low (26.9%), medium (43.1%; referent), increasing (6.9%), decreasing (18.1%), and high (4.8%). In adjusted models, the likelihoods of being frail were statistically higher for women in the increasing (odds ratio (OR) = 1.29, 95% confidence interval (CI): 1.03, 1.61) and high (OR = 1.42, 95% CI: 1.10, 1.84) trajectories. In contrast, women in the low trajectory group were less likely to be frail (OR = 0.86, 95% CI: 0.75, 0.98), and there was no difference in the likelihood of frailty in the decreasing trajectory group. Our study suggests that patterns of sitting time over 12 years in middle-aged women predict frailty in older age.

Associations of Physical Behaviours and Behavioural Reallocations with Markers of Metabolic Health: A Compositional Data Analysis

Standard statistical modelling has shown that the reallocation of sitting time to either standing or stepping may be beneficial for metabolic health. However, this overlooks the inherent dependency of time spent in all behaviours. The aim is to examine the associations between physical behaviours and markers of metabolic health (fasting glucose, fasting insulin, 2-h glucose, 2-h insulin, Homeostasis Model Assessment of Insulin Sensitivity (HOMA-IS), Matsuda Insulin Sensitivity Index (Matsuda-ISI) while quantifying the associations of reallocating time from one physical behaviour to another using compositional analysis. Objectively measured physical behaviour data were analysed (n = 435) using compositional analysis and compositional isotemporal substitutions to estimate the association of reallocating time from one behaviour to another in a population at high risk of type 2 diabetes mellitus (T2DM). Stepping time was associated with all markers of metabolic health relative to all other behaviours. Reallocating 30 min from sleep, sitting, or standing to stepping was associated with 5⁻6 fold lower 2-h glucose, 15⁻17 fold lower 2-h insulin, and higher insulin sensitivity (10⁻11 fold via HOMA-IS, 12⁻15 fold via Matsuda-ISI). Associations of reallocating time from any behaviour to stepping were maintained for 2-h glucose, 2-h insulin, and Matsuda-ISI after further adjusting for body mass index (BMI). Relocating time from stepping into sleep, sitting, or standing was associated with lower insulin sensitivity. Stepping time may be the most important behavioural composition when promoting improved metabolic health in adults at risk of T2DM.

What strategies do desk-based workers choose to reduce sitting time and how well do they work? Findings from a cluster randomised controlled trial

Background

Large amounts of sitting at work have been identified as an emerging occupational health risk, and findings from intervention trials have been reported. However, few such reports have examined participant-selected strategies and their relationships with behaviour change.

Methods

The Stand Up Victoria cluster-randomised controlled trial was a workplace-delivered intervention comprising organisational, environmental and individual level behaviour change strategies aimed at reducing sitting time in desk-based workers. Sit-stand workstations were provided, and participants (n = 134; intervention group only) were guided by health coaches to identify strategies for the ‘Stand Up’, ‘Sit Less’, and ‘Move More’ intervention targets, including how long they would stand using the workstation. Three-month workplace sitting and activity changes (activPAL3-assessed total sitting, prolonged sitting (i.e., sitting ≥30 min continuously) and purposeful walking) were evaluated in relation to the number (regression analysis) and types of strategies (decision-tree analysis).

Results

Over 80 different strategies were nominated by participants. Each additional strategy nominated for the ‘Stand Up’ intervention target (i.e. number of strategies) was associated with a reduction in prolonged sitting of 27.6 min/8-h workday (95% CI: -53.1, − 2.1, p = 0.034). Types of strategies were categorised into 13 distinct categories. Strategies that were task-based and phone-based were common across all three targets. The decision tree models did not select any specific strategy category as predicting changes in prolonged sitting (‘Stand Up’), however four strategy categories were identified as important for total sitting time (‘Sit Less’) and three strategy categories for purposeful walking (‘Moving More’). The uppermost nodes (foremost predictors) were nominating > 3 h/day of workstation standing (reducing total workplace sitting) and choosing a ‘Move More’ task-based strategy (purposeful walking).

Conclusions

Workers chose a wide range of strategies, with both strategy choice and strategy quantity appearing relevant to behavioural improvement. Findings support a tailored and pragmatic approach to encourage a change in sitting and activity in the workplace. Evaluating participant-selected strategies in the context of a successful intervention serves to highlight options that may prove feasible and effective in other desk-based workplace environments.

Trial registration

This trial was prospectively registered with the Australian New Zealand Clinical Trials register (ACTRN12611000742976) on 15 July 2011,

Electronic supplementary material

The online version of this article (10.1186/s12966-018-0731-z) contains supplementary material, which is available to authorized users.

The Role of Wearable Devices in Multiple Sclerosis

Multiple sclerosis (MS) is the most common neurological disorder in young adults. The prevalence of walking impairment in people with MS (pwMS) is estimated between 41% and 75%. To evaluate the walking capacity in pwMS, the patient reported outcomes (PROs) and performance-based tests (i.e., the 2-minute walk test, the 6-minute walk test, the Timed 25-Foot Walk Test, the Timed Up and Go Test, and the Six Spot Step Test) could be used. However, some studies point out that the results of both performance-based tests and objective measures (i.e., by accelerometer) could not reflect patient reports of walking performance and impact of MS on daily life. This review analyses different motion sensors embedded in smartphones and motion wearable device (MWD) that can be useful to measure free-living walking behavior, to evaluate falls, fatigue, sedentary lifestyle, exercise, and quality of sleep in everyday life of pwMS. Caveats and limitations of MWD such as variable accuracy, user adherence, power consumption and recharging, noise susceptibility, and data management are discussed as well.

Dimensions of sedentary behavior and objective cognitive functioning in breast cancer survivors

PURPOSE

To examine associations between dimensions of sedentary behavior and cognitive function in breast cancer survivors.

METHODS

Sedentary behavior variables were measured using thigh-worn activPALs, and included total daily sitting time, time in long sitting bouts, sit-to-stand transitions, and standing time. Cognitive function was assessed using the NIH Toolbox Cognitive Domain. Separate multivariable linear regression models were used to examine associations between sedentary behavior variables with the cognitive domain scores of attention, executive functioning, episodic memory, working memory, and information processing speed.

RESULTS

Thirty breast cancer survivors with a mean age of 62.2 (SD = 7.8) years who were 2.6 (SD = 1.1) years since diagnosis completed study assessments. In multivariable linear regression models, more time spent standing was associated with faster information processing (b: 5.78; p = 0.03), and more time spent in long sitting bouts was associated with worse executive function (b: -2.82; p = 0.02), after adjustment for covariates. No other sedentary behavior variables were statistically significantly associated with the cognitive domains examined in this study.

CONCLUSIONS

Two important sedentary constructs that are amenable to intervention, including time in prolonged sitting bouts and standing time, may be associated with cognitive function in breast cancer survivors. More research is needed to determine whether modifying these dimensions of sedentary behavior will improve cognitive function in women with a history of breast cancer, or prevent it from declining in breast cancer patients.

Methodological considerations of investigating adherence to using offloading devices among people with diabetes

Foot ulcers are a diabetic complication associated with significant morbidity, mortality, and amputation risk. Offloading devices prevent and heal foot ulcers, but adherence to using these devices is low. The reasons for nonadherence are unclear, and study results are difficult to compare due to methodological heterogeneity. This paper explores aspects of investigating adherence to using offloading devices among people with diabetes and provides recommendations for future studies, focusing on study designs, definitions of adherence, measurement methods, and conceptual frameworks. Most studies use a cross-sectional observational study design, limiting the potential to establish the temporal sequence between predictors and adherence, rule out confounding factors, and establish causality. Studies defining adherence as the length of time the device is worn have often used self-report to measure adherence, which may be unreliable. Studies using activity monitors to measure adherence have defined adherence as the number of steps taken with the device, which excludes weight-bearing activities where no steps are taken. Conceptual frameworks are not made explicit in the current quantitative research. It is concluded that future studies should use a longitudinal design with observational studies to identify patient groups prone to nonadherence and factors that influence adherence and experimental studies to evaluate interventions to improve adherence, focusing on these patient groups and factors. Furthermore, adherence should be defined in terms of relative adherence to using offloading devices during all weight-bearing activities, and objective measurement of adherence (using accelerometers and temperature monitors) should be used whenever possible. Clearly defined conceptual frameworks should guide the choice of factors to include in the study and the analysis of their interactions. By implementing these recommendations, research could provide a stronger evidence base in the future, supporting interventions to increase adherence and thereby improve outcomes for people with diabetic foot complications.

Ecological Momentary Assessment Is a Feasible and Valid Methodological Tool to Measure Older Adults' Physical Activity and Sedentary Behavior

Ecological momentary assessment (EMA) has the potential to yield new insights into the prediction and modeling of physical activity (PA) and sedentary behavior (SB). The objective of this study was to determine the feasibility and validity of an EMA protocol to assess older adults' PA and SB. Feasibility was determined by examining factors associated with EMA survey compliance and if PA or SB were impacted by EMA survey compliance. Validity was determined by comparing EMA-reported PA and SB to objectively measured PA and SB at the EMA prompt. Over 10 days, older adults (n = 104; Age_range = 60-98 years) received 6 randomly prompted EMA questionnaires on a smartphone each day and wore an ActivPAL activity monitor to provide a device-based measure of PA and SB. Participants reported whether they were currently engaged in PA or SB. Older adults were compliant with the EMA and ActivPAL protocol on 92% of occasions. Differences in EMA compliance differed by weight status. Among overweight and obese older adults EMA compliance differed by sex (OR = 3.15, 95% CI: 1.43, 6.92) and day of week (OR = 1.79, 95% CI: 1.33, 2.41). Among normal weight older adults, EMA compliance differed by time of day (OR = 1.52, 95% CI: 1.02, 2.30). EMA compliance did not differ for device-based PA or SB in the 15 min before versus the 15 min after the EMA prompt, suggesting that these behaviors did not influence likelihood of responding and responding did not influence these behaviors (ps > 0.05). When PA was reported through EMA, participants engaged in less device-based PA in the 15 min after compared to the 15 min before the EMA prompt (p = 0.01), suggesting possible reactance or a disruption of PA. EMA-reported PA and SB were positively associated with higher device-based PA and SB in the ±15 min, respectively, supporting criterion validity (ps < 0.05). The assessment of older adults' PA and SB through EMA is feasible and valid, although there may be PA reactance to EMA prompting. Therefore, EMA represents a significant methodological tool that can aid in our understanding of the environmental, social, and psychological processes regulating older adults' PA and SB in the context of everyday life.

Best practice guidelines for the measurement of physical activity levels in stroke survivors: a secondary analysis of an observational study

The aim of this study was to investigate the phenomenon of activity (increased activity in response to monitor wear) and determine the minimum wear time of accelerometers when objectively measuring habitual physical activity levels of community dwelling stroke survivors. Exploratory, secondary analyses of cross-sectional data were carried out. Physical activity variables [sitting, standing and stepping time, step count, light physical activity and moderate-to-vigorous physical activity (MVPA)] were measured with two activity monitors for 7 days. Repeated-measures analysis of variance was used to assess reactivity. Minimum wear time was assessed using regression analyses and median absolute differences. Paired t-tests were used to assess differences between weekend and weekday activity levels. There was no evidence of reactivity. Minimum wear time was 3 days for all activity variables, with the exception of MVPA, for which 7 days of monitoring was required. There were no significant differences in weekend and weekday activity levels. To accurately measure activity levels of individuals with stroke, we recommend 3 days of monitoring for all activity variables, with the exception of MVPA, which requires 7 days.

Subjective and objective assessment of sedentary behavior among college employees

BACKGROUND

High levels of sedentary behavior are linked to increased mortality. In the United States, individuals spend 55-70% of their waking day being sedentary. Since most individuals spend large portions of their daily lives at work, quantifying the time engaged in sedentary behavior at work is emerging as an important health determinant. Studies profiling academic institutions, where a variety of personnel with diverse job descriptions are employed, are limited. Available studies focus mostly on subjective methods, with few using objective approaches. Therefore, the purpose of the current study was to assess sedentary behavior among all occupational groups of a college in the Northeastern United States utilizing both a subjective and an objective method.

METHODS

College employees (n = 367) completed the Occupational Sitting and Physical Activity Questionnaire (OSPAQ). A sub-sample of these employees (n = 127) subsequently wore an activPAL3 accelerometer 24 h per day for seven consecutive days. Outcome variables were time spent sitting, standing, stepping, and total number of steps. To assess fragmentation of sedentary behavior, the average duration of a sitting bout and sitting bouts/sitting hour were calculated. Differences between administrators, faculty, and staff, were analyzed using multivariate and univariate analyses of variance.

RESULTS

The OSPAQ results indicated that administrators spent more of their working day sedentary (73.2 ± 17.7%) than faculty members (58.5 ± 19.6%, p < 0.05). For the objective phase of the study, complete data were analyzed from 86 participants. During a waking day, administrators (64.0 ± 8.1%) were more sedentary than faculty (56.0 ± 7.9%, p < 0.05) and fragmented their sitting less than staff (3.7 ± 0.7 and 4.5 ± 7.9 bouts of sitting/sitting hour, respectively; p < 0.05). This pattern was also seen during working hours, with administrators (4.9 ± 2.1) taking fewer breaks per hour than staff (6.9 ± 3.0, p < 0.05).

CONCLUSIONS

Administrators are the most sedentary members of the campus community. However, overall, the level of sedentary behavior among employees was high. This study highlights the need for sedentary behavior interventions in the college/university environment.

Occupational Physical Activity Habits of UK Office Workers: Cross-Sectional Data from the Active Buildings Study

Habitual behaviours are learned responses that are triggered automatically by associated environmental cues. The unvarying nature of most workplace settings makes workplace physical activity a prime candidate for a habitual behaviour, yet the role of habit strength in occupational physical activity has not been investigated. Aims of the present study were to: (i) document occupational physical activity habit strength; and (ii) investigate associations between occupational activity habit strength and occupational physical activity levels. A sample of UK office-based workers (n = 116; 53% female, median age 40 years, SD 10.52) was fitted with activPAL accelerometers worn for 24 h on five consecutive days, providing an objective measure of occupational step counts, stepping time, sitting time, standing time and sit-to-stand transitions. A self-report index measured the automaticity of two occupational physical activities (“being active” (e.g., walking to printers and coffee machines) and “stair climbing”). Adjusted linear regression models investigated the association between occupational activity habit strength and objectively-measured occupational step counts, stepping time, sitting time, standing time and sit-to-stand transitions. Eighty-one per cent of the sample reported habits for “being active”, and 62% reported habits for “stair climbing”. In adjusted models, reported habit strength for “being active” were positively associated with average occupational sit-to-stand transitions per hour (B = 0.340, 95% CI: 0.053 to 0.627, p = 0.021). “Stair climbing” habit strength was unexpectedly negatively associated with average hourly stepping time (B = −0.01, 95% CI: −0.01 to −0.00, p = 0.006) and average hourly occupational step count (B = −38.34, 95% CI: −72.81 to −3.88, p = 0.030), which may reflect that people with stronger stair-climbing habits compensate by walking fewer steps overall. Results suggest that stair-climbing and office-based occupational activity can be habitual. Interventions might fruitfully promote habitual workplace activity, although, in light of potential compensation effects, such interventions should perhaps focus on promoting moderate-intensity activity.

Association of sitting time and breaks in sitting with muscle mass, strength, function, and inflammation in community-dwelling older adults

The mechanisms through which excessive sitting time impacts health are important to understand. This study found that each hour of sitting per day was not associated with physical function, although associations with poor body composition were observed. Reducing sitting time for improved weight management in older adults needs further exploration.

INTRODUCTION

To examine the association of sitting time and breaks in sitting time with muscle mass, strength, function, and inflammation in older Australians.

METHODS

Data from the thigh-worn activPAL3™ monitor (7-day continuous wear) was used to derive time spent sitting (hours) and total number of sit-stand transitions per day. Body composition (dual energy X-ray absorptiometry), lower-body muscle strength, function (timed up-and-go [TUG], 4-m gait speed, four square step test, 30-second sit-to-stand), and serum inflammatory markers (interleukin-[IL-6], IL-8, IL-10, tumor necrosis factor-alpha [TNF-α], and adiponectin) were measured. Multiple regression analyses, adjusted for age, sex, ethnicity, education, employment status, marital status, number of prescription medications, smoking status, vitamin D, and stepping time, were used to assess the associations.

RESULTS

Data from 123 community-dwelling older adults (aged 65-84 years, 63% female) were used. Total daily sitting time was associated with lower percentage lean mass (β [95%CI], - 1.70% [- 2.30, - 1.10]) and higher total body fat mass (2.92 kg [1.94, 3.30]). More frequent breaks in sitting time were associated with a 45% reduced risk of having pre-sarcopenia (OR = 0.55; 95% CI 0.34, 0.91; model 1), defined as appendicular lean mass divided by BMI. No significant associations were observed for sitting time or breaks in sitting with measures of muscle strength, function, or inflammation.

CONCLUSION

In older community-dwelling adults, greater sitting time was associated with a lower percentage lean mass, while more frequent breaks in sitting time were associated with lower odds of having pre-sarcopenia. This suggests that reducing sedentary time and introducing frequent breaks in sedentary time may be beneficial for improving body composition in healthy older adults.

Associations between the Objectively Measured Office Environment and Workplace Step Count and Sitting Time: Cross-Sectional Analyses from the Active Buildings Study

Office-based workers spend a large proportion of the day sitting and tend to have low overall activity levels. Despite some evidence that features of the external physical environment are associated with physical activity, little is known about the influence of the spatial layout of the internal environment on movement, and the majority of data use self-report. This study investigated associations between objectively-measured sitting time and activity levels and the spatial layout of office floors in a sample of UK office-based workers. Participants wore activPAL accelerometers for at least three consecutive workdays. Primary outcomes were steps and proportion of sitting time per working hour. Primary exposures were office spatial layout, which was objectively-measured by deriving key spatial variables: ‘distance from each workstation to key office destinations’, ‘distance from participant’s workstation to all other workstations’, ‘visibility of co-workers’, and workstation ‘closeness’. 131 participants from 10 organisations were included. Fifty-four per cent were female, 81% were white, and the majority had a managerial or professional role (72%) in their organisation. The average proportion of the working hour spent sitting was 0.7 (SD 0.15); participants took on average 444 (SD 210) steps per working hour. Models adjusted for confounders revealed significant negative associations between step count and distance from each workstation to all other office destinations (e.g., B = −4.66, 95% CI: −8.12, −1.12, p < 0.01) and nearest office destinations (e.g., B = −6.45, 95% CI: −11.88, −0.41, p < 0.05) and visibility of workstations when standing (B = −2.35, 95% CI: −3.53, −1.18, p < 0.001). The magnitude of these associations was small. There were no associations between spatial variables and sitting time per work hour. Contrary to our hypothesis, the further participants were from office destinations the less they walked, suggesting that changing the relative distance between workstations and other destinations on the same floor may not be the most fruitful target for promoting walking and reducing sitting in the workplace. However, reported effect sizes were very small and based on cross-sectional analyses. The approaches developed in this study could be applied to other office buildings to establish whether a specific office typology may yield more promising results.

Putative mechanisms Underlying Myocardial infarction onset and Emotions (PUME): a randomised controlled study protocol

INTRODUCTION

The experience of negative emotions (eg, anger, anxiety and sadness) is associated with an increased short-term risk of incident cardiovascular disease (CVD) events, independent of traditional CVD risk factors. Impairment in endothelial function is one possible biological mechanism which may explain the association between negative emotions and incident CVD events. This laboratory-based, single-blind, randomised controlled experimental study aims to investigate the impact of induced negative emotions including anger, anxiety and sadness on endothelial function.

METHODS AND ANALYSIS

In a between-subjects design, 280 healthy participants are randomised to one of four experimental negative emotion inductions: anger, anxiety, sadness or a neutral condition. Endothelium-dependent vasodilation, circulating levels of endothelial cell-derived microparticles and bone marrow-derived endothelial progenitor cells, and indices of nitric oxide inhibition are assessed before and 3, 40, 70 and 100 min after negative emotion induction. Finally, in a subsample of 84 participants, the potential moderating effects of cardiorespiratory fitness and habitual physical activity on the adverse effects of an acute negative emotion on endothelial function are investigated.

ETHICS AND DISSEMINATION

This study is conducted in compliance with the Helsinki Declaration and the Columbia University Medical Center Institutional Review Board. The results of the study will be disseminated at several research conferences and as published articles in peer reviewed journals. The study will be implemented and reported in line with the SPIRIT statement.

TRIAL REGISTRATION NUMBER

NCT01909895; Pre-results.

Defining Accelerometer Nonwear Time to Maximize Detection of Sedentary Time in Youth

PURPOSE

The present study examined various accelerometer nonwear definitions and their impact on detection of sedentary time using different ActiGraph models, filters, and axes.

METHODS

In total, 61 youth (34 children and 27 adolescents; aged 5-17 y) wore a 7164 and GT3X+ ActiGraph on a hip-worn belt during a 90-minute structured sedentary activity. Data from GT3X+ were downloaded using the Normal filter (N) and low-frequency extension (LFE), and vertical axis (V) and vector magnitude (VM) counts were examined. Nine nonwear definitions were applied to the 7164 model (V), GT3X+LFE (V and VM), and GT3X+N (V and VM), and sedentary estimates were computed.

RESULTS

The GT3X+LFE-VM was most sensitive to movement and could accurately detect observed sedentary time with the shortest nonwear definition of 20 minutes of consecutive "0" counts for children and 40 minutes for adolescents. The GT3X+N-V was least sensitive to movement and required longer definitions to detect observed sedentary time (40 min for children and 90 min for adolescents). VM definitions were 10 minutes shorter than V definitions. LFE definitions were 40 minutes shorter than N definitions in adolescents.

CONCLUSION

Different nonwear definitions are needed for children and adolescents and for different model-filter-axis types. Authors need to consider nonwear definitions when comparing prevalence rates of sedentary behavior across studies.

Reliability, minimal detectable change and responsiveness to change: Indicators to select the best method to measure sedentary behaviour in older adults in different study designs

Introduction

Prolonged sedentary behaviour (SB) is associated with poor health. It is unclear which SB measure is most appropriate for interventions and population surveillance to measure and interpret change in behaviour in older adults. The aims of this study: to examine the relative and absolute reliability, Minimal Detectable Change (MDC) and responsiveness to change of subjective and objective methods of measuring SB in older adults and give recommendations of use for different study designs.

Methods

SB of 18 older adults (aged 71 (IQR 7) years) was assessed using a systematic set of six subjective tools, derived from the TAxonomy of Self report Sedentary behaviour Tools (TASST), and one objective tool (activPAL3c), over 14 days. Relative reliability (Intra Class Correlation coefficients-ICC), absolute reliability (SEM), MDC, and the relative responsiveness (Cohen’s d effect size (ES) and Guyatt’s Responsiveness coefficient (GR)) were calculated for each of the different tools and ranked for different study designs.

Results

ICC ranged from 0.414 to 0.946, SEM from 36.03 to 137.01 min, MDC from 1.66 to 8.42 hours, ES from 0.017 to 0.259 and GR from 0.024 to 0.485. Objective average day per week measurement ranked as most responsive in a clinical practice setting, whereas a one day measurement ranked highest in quasi-experimental, longitudinal and controlled trial study designs. TV viewing–Previous Week Recall (PWR) ranked as most responsive subjective measure in all study designs.

Conclusions

The reliability, Minimal Detectable Change and responsiveness to change of subjective and objective methods of measuring SB is context dependent. Although TV viewing-PWR is the more reliable and responsive subjective method in most situations, it may have limitations as a reliable measure of total SB. Results of this study can be used to guide choice of tools for detecting change in sedentary behaviour in older adults in the contexts of population surveillance, intervention evaluation and individual care.

Data correction for seven activity trackers based on regression models

Using an activity tracker for measuring activity-related parameters, e.g. steps and energy expenditure (EE), can be very helpful in assisting a person's fitness improvement. Unlike the measuring of number of steps, an accurate EE estimation requires additional personal information as well as accurate velocity of movement, which is hard to achieve due to inaccuracy of sensors. In this paper, we have evaluated regression-based models to improve the precision for both steps and EE estimation. For this purpose, data of seven activity trackers and two reference devices was collected from 20 young adult volunteers wearing all devices at once in three different tests, namely 60-minute office work, 6-hour overall activity and 60-minute walking. Reference data is used to create regression models for each device and relative percentage errors of adjusted values are then statistically compared to that of original values. The effectiveness of regression models are determined based on the result of a statistical test. During a walking period, EE measurement was improved in all devices. The step measurement was also improved in five of them. The results show that improvement of EE estimation is possible only with low-cost implementation of fitting model over the collected data e.g. in the app or in corresponding service back-end.

Validation of the VitaBit Sit-Stand Tracker: Detecting Sitting, Standing, and Activity Patterns

Sedentary behavior (SB) has detrimental consequences and cannot be compensated for through moderate-to-vigorous physical activity (PA). In order to understand and mitigate SB, tools for measuring and monitoring SB are essential. While current direct-to-customer wearables focus on PA, the VitaBit validated in this study was developed to focus on SB. It was tested in a laboratory and in a free-living condition, comparing it to direct observation and to a current best-practice device, the ActiGraph, on a minute-by-minute basis. In the laboratory, the VitaBit yielded specificity and negative predictive rates (NPR) of above 91.2% for sitting and standing, while sensitivity and precision ranged from 74.6% to 85.7%. For walking, all performance values exceeded 97.3%. In the free-living condition, the device revealed performance of over 72.6% for sitting with the ActiGraph as criterion. While sensitivity and precision for standing and walking ranged from 48.2% to 68.7%, specificity and NPR exceeded 83.9%. According to the laboratory findings, high performance for sitting, standing, and walking makes the VitaBit eligible for SB monitoring. As the results are not transferrable to daily life activities, a direct observation study in a free-living setting is recommended.

Research Strategies for Nutritional and Physical Activity Epidemiology and Cancer Prevention

Very large international and ethnic differences in cancer rates exist, are minimally explained by genetic factors, and show the huge potential for cancer prevention. A substantial portion of the differences in cancer rates can be explained by modifiable factors, and many important relationships have been documented between diet, physical activity, and obesity, and incidence of important cancers. Other related factors, such as the microbiome and the metabolome, are emerging as important intermediary components in cancer prevention. It is possible with the incorporation of newer technologies and studies including long follow-up and evaluation of effects across the life cycle, additional convincing results will be produced. However, several challenges exist for cancer researchers; for example, measurement of diet and physical activity, and lack of standardization of samples for microbiome collection, and validation of metabolomic studies. The United States National Cancer Institute convened the Research Strategies for Nutritional and Physical Activity Epidemiology and Cancer Prevention Workshop on June 28-29, 2016, in Rockville, Maryland, during which the experts addressed the state of the science and areas of emphasis. This current paper reflects the state of the science and priorities for future research. Cancer Epidemiol Biomarkers Prev; 27(3); 233-44. ©2017 AACR.

Prediction of sustained harmonic walking in the free-living environment using raw accelerometry data

OBJECTIVE

Using raw, sub-second-level accelerometry data, we propose and validate a method for identifying and characterizing walking in the free-living environment. We focus on sustained harmonic walking (SHW), which we define as walking for at least 10 s with low variability of step frequency.

APPROACH

We utilize the harmonic nature of SHW and quantify the local periodicity of the tri-axial raw accelerometry data. We also estimate the fundamental frequency of the observed signals and link it to the instantaneous walking (step-to-step) frequency (IWF). Next, we report the total time spent in SHW, number and durations of SHW bouts, time of the day when SHW occurred, and IWF for 49 healthy, elderly individuals.

MAIN RESULTS

The sensitivity of the proposed classification method was found to be 97%, while specificity ranged between 87% and 97% and the prediction accuracy ranged between 94% and 97%. We report the total time in SHW between 140 and 10 min d^-1 distributed between 340 and 50 bouts. We estimate the average IWF to be 1.7 steps-per-second.

SIGNIFICANCE

We propose a simple approach for the detection of SHW and estimation of IWF, based on Fourier decomposition.

Systematic comparative validation of self-report measures of sedentary time against an objective measure of postural sitting (activPAL)

BACKGROUND

Sedentary behaviour is a public health concern that requires surveillance and epidemiological research. For such large scale studies, self-report tools are a pragmatic measurement solution. A large number of self-report tools are currently in use, but few have been validated against an objective measure of sedentary time and there is no comparative information between tools to guide choice or to enable comparison between studies. The aim of this study was to provide a systematic comparison, generalisable to all tools, of the validity of self-report measures of sedentary time against a gold standard sedentary time objective monitor.

METHODS

Cross sectional data from three cohorts (N = 700) were used in this validation study. Eighteen self-report measures of sedentary time, based on the TAxonomy of Self-report SB Tools (TASST) framework, were compared against an objective measure of postural sitting (activPAL) to provide information, generalizable to all existing tools, on agreement and precision using Bland-Altman statistics, on criterion validity using Pearson correlation, and on data loss.

RESULTS

All self-report measures showed poor accuracy compared with the objective measure of sedentary time, with very wide limits of agreement and poor precision (random error > 2.5 h). Most tools under-reported total sedentary time and demonstrated low correlations with objective data. The type of assessment used by the tool, whether direct, proxy, or a composite measure, influenced the measurement characteristics. Proxy measures (TV time) and single item direct measures using a visual analogue scale to assess the proportion of the day spent sitting, showed the best combination of precision and data loss. The recall period (e.g. previous week) had little influence on measurement characteristics.

CONCLUSION

Self-report measures of sedentary time result in large bias, poor precision and low correlation with an objective measure of sedentary time. Choice of tool depends on the research context, design and question. Choice can be guided by this systematic comparative validation and, in the case of population surveillance, it recommends to use a visual analog scale and a 7 day recall period. Comparison between studies and improving population estimates of average sedentary time, is possible with the comparative correction factors provided.

A systematic literature review of reviews on techniques for physical activity measurement in adults: a DEDIPAC study

The links between increased participation in Physical Activity (PA) and improvements in health are well established. As this body of evidence has grown, so too has the search for measures of PA with high levels of methodological effectiveness (i.e. validity, reliability and responsiveness to change). The aim of this “review of reviews” was to provide a comprehensive overview of the methodological effectiveness of currently employed measures of PA, to aid researchers in their selection of an appropriate tool. A total of 63 review articles were included in this review, and the original articles cited by these reviews were included in order to extract detailed information on methodological effectiveness.

Self-report measures of PA have been most frequently examined for methodological effectiveness, with highly variable findings identified across a broad range of behaviours. The evidence-base for the methodological effectiveness of objective monitors, particularly accelerometers/activity monitors, is increasing, with lower levels of variability observed for validity and reliability when compared to subjective measures. Unfortunately, responsiveness to change across all measures and behaviours remains under-researched, with limited information available.

Other criteria beyond methodological effectiveness often influence tool selection, including cost and feasibility. However, researchers must be aware of the methodological effectiveness of any measure selected for use when examining PA. Although no “perfect” tool for the examination of PA in adults exists, it is suggested that researchers aim to incorporate appropriate objective measures, specific to the behaviours of interests, when examining PA in free-living environments.

Physical performance following acute high-risk abdominal surgery: a prospective cohort study

BACKGROUND

Acute high-risk abdominal (AHA) surgery is associated with high mortality, multiple postoperative complications and prolonged hospital stay. Further development of strategies for enhanced recovery programs following AHA surgery is needed. The aim of this study was to describe physical performance and barriers to independent mobilization among patients who received AHA surgery (postoperative days [POD] 1-7).

METHODS

Patients undergoing AHA surgery were consecutively enrolled from a university hospital in Denmark. In the first postoperative week, all patients were evaluated daily with regards to physical performance, using the Cumulated Ambulation Score (CAS; 0-6 points) to assess basic mobility and the activPAL monitor to assess the 24-hour physical activity level. We recorded barriers to independent mobilization.

RESULTS

Fifty patients undergoing AHA surgery (mean age 61.4 ± 17.2 years) were included. Seven patients died within the first postoperative week, and 15 of 43 (35%) patients were still not independently mobilized (CAS < 6) on POD-7, which was associated with pulmonary complications developing (53% v. 14% in those with CAS = 6, p = 0.012). The patients lay or sat for a median of 23.4 hours daily during the first week after AHA surgery, and the main barriers to independent mobilization were fatigue and abdominal pain.

CONCLUSION

Patients who receive AHA surgery have very limited physical performance in the first postoperative week. Barriers to independent mobilization are primarily fatigue and abdominal pain. Further studies investigating strategies for early mobilization and barriers to mobilization in the immediate postoperative period after AHA surgery are needed.

A randomised feasibility study to investigate the impact of education and the addition of prompts on the sedentary behaviour of office workers

Background

Office workers have been identified as being at risk of accumulating high amounts of sedentary time in prolonged events during work hours, which has been associated with increased risk of a number of long-term health conditions.

There is some evidence that providing advice to stand at regular intervals during the working day, and using computer-based prompts, can reduce sedentary behaviour in office workers. However, evidence of effectiveness, feasibility and acceptability for these types of intervention is currently limited.

Methods

A 2-arm, parallel group, cluster-randomised feasibility trial to assess the acceptability of prompts to break up sedentary behaviour was conducted with office workers in a commercial bank (n = 21). Participants were assigned to an education only group (EG) or prompt and education group (PG). Both groups received education on reducing and breaking up sitting at work, and the PG also received hourly prompts, delivered by Microsoft Outlook over 10 weeks, reminding them to stand. Objective measurements of sedentary behaviour were made using activPAL monitors worn at three time points: baseline, in the last 2 weeks of the intervention period and 12 weeks after the intervention. Focus groups were conducted to explore the acceptability of the intervention and the motivations and barriers to changing sedentary behaviour.

Results

Randomly generated, customised prompts, delivered by Microsoft Outlook, with messages about breaking up sitting, proved to be a feasible and acceptable way of delivering prompts to office workers. Participants in both groups reduced their sitting, but changes were not maintained at follow-up. The education session seemed to increase outcome expectations of the benefits of changing sedentary behaviour and promote self-regulation of behaviour in some participants. However, low self-efficacy and a desire to conform to cultural norms were barriers to changing behaviour.

Conclusions

Prompts delivered by Microsoft Outlook were a feasible, low-cost way of prompting office workers to break up their sedentary behaviour, although further research is needed to determine whether this has an additional impact on sedentary behaviour, to education alone. The role of cultural norms, and promoting self-efficacy, should be considered in the design of future interventions.

Trial registration

This study was registered retrospectively as a clinical trial on ClinicalTrials.gov (ID no. NCT02609282) on 23 March 2015.

Classification and characterization of postural transitions using instrumented shoes

The frequency and quality of sit-to-stand and stand-to-sit postural transitions decrease with age and are highly relevant for fall risk assessment. Accurate classification and characterization of these transitions in daily life of older adults are therefore needed. In this study, we propose to use instrumented shoes for postural transition classification as well as transition duration estimation from insole force signals. In the first part, data were collected with 10 older adults and 10 young participants performing transitions in the laboratory while wearing the instrumented shoes, without arm assistance. A wavelet approach was used to transform the insole force data, and candidate events were selected for transition duration estimation. Transition durations were then validated against a model based on force plate reference. Vertical force estimation was also compared to force plate measurement. In the second part, postural transitions were classified in daily life using the instrumented shoes and validated against a highly accurate wearable system. Transition duration was estimated with an error ranging from 10 to 20% while the error for vertical force estimation was 7%. Postural transition classification was achieved with excellent sensitivity and precision exceeding 90%. In conclusion, the instrumented shoes are suitable for classifying and characterizing postural transitions in daily life conditions of healthy older adults. Graphical abstract "Experimental setup showing instrumented shoes, reference force plate, as well as IMUs used for postural transition classification and duration estimation comparison".

Objectively Measured Physical Activity and Sedentary Behavior in Successful Weight Loss Maintainers

OBJECTIVE

The objective of this study was to compare patterns of objectively measured moderate-to-vigorous physical activity (MVPA, ≥ 3.00 metabolic equivalents [METs]), light-intensity physical activity (LPA, 1.50-2.99 METs), and sedentary behavior (SB, < 1.50 METs) in successful weight loss maintainers (WLMs), normal weight controls (NC), and controls with overweight/obesity (OC).

METHODS

Participants (18-65 y) were recruited in three groups: WLM (maintaining ≥ 13.6-kg weight loss for ≥ 1 year, n = 30), NC (BMI matched to current BMI of WLM, n = 33), and OC (BMI matched to pre-weight loss BMI of WLM, n = 27). All participants wore the activPAL for 1 week.

RESULTS

Compared with OC and NC, WLM spent more awake time in total MVPA (WLM: 9.6 ± 3.9%, NC: 7.1 ± 2.1%, OC: 5.9 ± 2.0%; P < 0.01) and more time in sustained (≥ 10 min) bouts of MVPA (WLM: 39 ± 33, NC: 17 ± 14, OC: 9 ± 11 min/d; P < 0.01). Compared with OC, WLM and NC spent more awake time in LPA (WLM: 29.6 ± 7.9%, NC: 29.1 ± 8.3%, OC: 24.8 ± 6.7%; P = 0.04) and less awake time sedentary (WLM: 60.8 ± 9.3%, NC: 63.8 ± 9.5%, OC: 69.3 ± 7.5%; P < 0.01).

CONCLUSIONS

Results provide additional data supporting the important role of MVPA in weight loss maintenance and suggest notable differences in LPA and SB between normal weight individuals and those with overweight/obesity. Increasing LPA and/or decreasing SB may be additional potential targets for weight management interventions.

Assessment of Physical Activity of Hospitalised Older Adults: A Systematic Review

BACKGROUND

The assessment of physical activity levels of hospitalised older people requires accurate and reliable measures. Physical activities that older people in hospital commonly engage in include exercises and walking. Measurement of physical activity levels of older inpatients is essential to evaluate the impact of interventions to improve physical activity levels and to determine associations between physical activity in hospital and other health-related outcome measures.

OBJECTIVE

To determine which measures are used to measure physical activity of older people in hospital, and to describe their properties and applications.

METHOD

A systematic review of four databases: Medline, Embase, CINAHL and AMED was conducted for papers published from 1996 to 2016. Inclusion criteria were participants aged ≥ 65 years and studies which included measures of physical activity in the acute medical inpatient setting. Studies which specifically assessed the activity levels of surgical patients or patients with neurological conditions such as stroke or brain injury were excluded. All study designs were included in the review.

RESULTS

18 studies were included from 127 articles selected for full review. 15 studies used objective measures to measure the physical activity of older inpatients: 11 studies used accelerometers and four used direct systematic observations. Seven accelerometers were identified including the StepWatch Activity Monitor, activPAL, GENEActiv, Kenz Lifecorder EX, Actiwatch-L, Tractivity and AugmenTech Inc. Pittsburgh accelerometer. Three studies used a subjective measure (interviews with nurses and patients) to classify patients into low, intermediate and high mobility groups. The StepWatch Activity Monitor was reported to be most accurate at step-counting in patients with slow gait speed or altered gait. The activPAL was reported to be highly accurate at classifying postures.

CONCLUSION

Physical activity levels of older inpatients can be measured using accelerometers. The accuracy of the accelerometers varies between devices and population-specific validation studies are needed to determine their suitability in measuring physical activity levels of hospitalised older people. Subjective measures are less accurate but can be a practical way of measuring physical activity in a larger group of patients.

Transforming growth factor beta (TGF-β) in adolescent chronic fatigue syndrome

BACKGROUND

Chronic fatigue syndrome (CFS) is a prevalent and disabling condition among adolescent. The disease mechanisms are unknown. Previous studies have suggested elevated plasma levels of several cytokines, but a recent meta-analysis of 38 articles found that of 77 different cytokines measured in plasma, transforming growth factor beta (TGF-β) was the only one that was elevated in patients compared to controls in a sufficient number of articles. In the present study we therefore compared the plasma levels of the three TGF-β isoforms in adolescent CFS patients and healthy controls. In addition, the study explored associations between TGF-β levels, neuroendocrine markers, clinical markers and differentially expressed genes within the CFS group.

METHODS

CFS patients aged 12-18 years (n = 120) were recruited nation-wide to a single referral center as part of the NorCAPITAL project (ClinicalTrials ID: NCT01040429). A broad case definition of CFS was applied, requiring 3 months of unexplained, disabling chronic/relapsing fatigue of new onset, whereas no accompanying symptoms were necessary. Healthy controls (n = 68) were recruited from local schools. The three isoforms of TGF-β (TGF-β1, TGF-β2, TGF-β3) were assayed using multiplex technology. Neuroendocrine markers encompassed plasma and urine levels of catecholamines and cortisol, as well as heart rate variability indices. Clinical markers consisted of questionnaire scores for symptoms of post-exertional malaise, inflammation, fatigue, depression and trait anxiety, as well as activity recordings. Whole blood gene expression was assessed by RNA sequencing in a subgroup of patients (n = 29) and controls (n = 18).

RESULTS

Plasma levels of all three isoforms of TGF-β were equal in the CFS patients and the healthy controls. Subgrouping according to the Fukuda and Canada 2003 criteria of CFS did not reveal differential results. Within the CFS group, all isoforms of TGF-β were associated with plasma cortisol, urine norepinephrine and urine epinephrine, and this association pattern was related to fatigue score. Also, TGF-β3 was related to expression of the B cell annotated genes TNFRSF13C and CXCR5.

CONCLUSIONS

Plasma levels of all TGF-β isoforms were not altered in adolescent CFS. However, the TGF-β isoforms were associated with neuroendocrine markers, an association related to fatigue score. Furthermore, TGF-β3 might partly mediate an association between plasma cortisol and B cell gene expression. Trial registration Clinical Trials NCT01040429.

Physical performance following acute high-risk abdominal surgery: a prospective cohort study

BACKGROUND

Acute high-risk abdominal (AHA) surgery is associated with high mortality, multiple postoperative complications and prolonged hospital stay. Further development of strategies for enhanced recovery programs following AHA surgery is needed. The aim of this study was to describe physical performance and barriers to independent mobilization among patients who received AHA surgery (postoperative days [POD] 1-7).

METHODS

Patients undergoing AHA surgery were consecutively enrolled from a university hospital in Denmark. In the first postoperative week, all patients were evaluated daily with regards to physical performance, using the Cumulated Ambulation Score (CAS; 0-6 points) to assess basic mobility and the activPAL monitor to assess the 24-hour physical activity level. We recorded barriers to independent mobilization.

RESULTS

Fifty patients undergoing AHA surgery (mean age 61.4 ± 17.2 years) were included. Seven patients died within the first postoperative week, and 15 of 43 (35%) patients were still not independently mobilized (CAS < 6) on POD-7, which was associated with pulmonary complications developing (53% v. 14% in those with CAS = 6, p = 0.012). The patients lay or sat for a median of 23.4 hours daily during the first week after AHA surgery, and the main barriers to independent mobilization were fatigue and abdominal pain.

CONCLUSION

Patients who receive AHA surgery have very limited physical performance in the first postoperative week. Barriers to independent mobilization are primarily fatigue and abdominal pain. Further studies investigating strategies for early mobilization and barriers to mobilization in the immediate postoperative period after AHA surgery are needed.

Comparison of subjective and objective measures of office workers' sedentary time

Sedentary behavior is an independent and prominent risk factor for chronic disease. Occupational sitting is likely to be the largest determinant of overall daily sitting time. Gathering accurate data on sedentary behaviors is essential to determine prevalence and effectiveness of interventions to reduce sedentary time. The purpose of this research was to determine whether self-reported sedentary time assessed by the Paffenbarger Physical Activity Questionnaire (PPAQ) and the Occupational Sitting and Physical Activity Questionnaire (OSPAQ) was related to objectively assessed sedentary time by the activPAL3 activity monitor. In the spring of 2015, 44 women employed full-time at Slippery Rock University participated in this study. Participants were predominantly Caucasian (95%), middle-aged (48 ± 10 years), and had an average BMI of 30.5 ± 8.2. A positive, weak correlation was found in sedentary time between the PPAQ (14.65 ± 2.77 h) and the activPAL3 (17.71 ± 1.46 h) over a 24 hour day (r = 0.253; p = 0.098; n = 44). Thirty-nine of the 44 participants significantly underestimated their sedentary time as compared to the activPAL3 (3.06 ± 2.76 h; p = 0.001). A positive, weak correlation was also found in sedentary time between the OSPAQ (5.96 ± 1.11 h) and the activPAL3 (5.69 ± 1.06 h) during the 8.5 hour work day (r = 0.100; p = 0.518; n = 44). Future studies examining sedentary behaviors should use caution when only considering the use of subjective recall surveys. This is especially true when self-reported behaviors are used to inform health promotion programs and create universal recommendations aimed to reduce sedentary time.

COPD online-rehabilitation versus conventional COPD rehabilitation - rationale and design for a multicenter randomized controlled trial study protocol (CORe trial)

BACKGROUND

Rehabilitation of patients with chronic obstructive pulmonary disease (COPD) is a key treatment in COPD. However, despite the existing evidence and a strong recommendation from lung associations worldwide, 50% of patients with COPD decline to participate in COPD rehabilitation program and 30-50% drop-out before completion. The main reasons are severe symptoms, inflexible accessibility and necessity for transportation. Currently there are no well-established and evident rehabilitation alternatives. Supervised online screen rehabilitation could be a useful approach to increase accessibility and compliance. The aim of this multicenter RCT study is to compare the potential benefits of a 10-week online COPD rehabilitation program (CORe) with conventional outpatient COPD rehabilitation (CCRe).

METHODS

This study is a randomized assessor- and statistician blinded superiority multicenter trial with two parallel groups, employing 1:1 allocation to the intervention and the comparison group.On the basis of a sample size calculation, 134 patients with severe or very severe COPD and eligible to conventional hospital based outpatient COPD rehabilitation will be included and randomized from eight different hospitals. The CORe intervention group receives group supervised resistance- and endurance training and patient education, 60 min, three times/week for 10 weeks at home via online-screen. The CCRe comparison group receives group based supervised resistance- and endurance training and patient education, 90 min, two times/week for 10 weeks (two hospitals) or 12 weeks (six hospitals) in groups at the local hospital. The primary outcome is change in the 6-min walking distance after 10/12 weeks; the secondary outcomes are changes in 30 s sit-to-stand chair test, physical activity level, symptoms, anxiety and depression symptoms, disease specific and generic quality of life. Primary endpoint is 10/12 weeks from baseline, while secondary endpoints are 22, 36, 62 weeks from baseline assessments.

DISCUSSION

The study will likely contribute to knowledge regarding COPD tele-rehabilitation and to which extent it is more feasible and thereby more efficient than conventional COPD rehabilitation in patients with severe and very severe COPD.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT02667171 . Registration data: January 28th 2016.

Exploring repositioning movements in sitting with 'at risk' groups using accelerometry and interface pressure mapping technologies

BACKGROUND

Despite high quality guidelines underpinning pressure ulcer care (NPUAP/EPUAP/PPPIA, 2014), pressure ulceration still poses a significant financial impact on health care services in treatment and staff costs as well as having a profound effect on the health and quality of life of individuals experiencing them. Repositioning is a key preventative technique recommended by occupational therapists and other health care professionals. The frequency and quality of repositioning movements performed by individuals, however, can be difficult to determine. This paper explores the use of technology in monitoring repositioning movements in sitting.

OBJECTIVE

To explore the outputs of technologies such as interface pressure mapping systems and accelerometers in enabling the therapist to accurately monitor seated behaviour and enhance practice through targeted interventions to prevent sitting acquired pressure ulceration.

METHOD

Reviewing the findings of two recent research studies with 'at risk' cohorts (spinal cord injury; elderly orthopaedic), using accelerometry and seated interface pressures, this paper will highlight how useful this technology is in clinical practice to monitor weight shifts and repositioning behaviours.

RESULT

Both studies illustrated that the majority of individuals did not adhere to the frequency or magnitude of movements currently recommended to redistribute seating interface pressures. When repositioning was performed it was ineffective in reducing seated pressures.

CONCLUSION

In an era of personalised medicine, technology has an important role to play in providing the service user, caregivers and healthcare staff with important biofeedback information about seated behaviours, particularly those that minimise the risk of developing sitting acquired pressure ulcers. This information can augment occupational therapists' clinical decision-making in maximising active pressure ulcer prevention.

Comparability of activity monitors used in Asian and Western-country studies for assessing free-living sedentary behaviour

This study aims to compare the outputs of the waist-worn Active style Pro HJA-350IT (ASP; used in studies with Asian populations), the waist-worn ActiGragh™GT3X+ using the normal filter (GT3X+) and the thigh-worn activPAL3 (AP) in assessing adults' sedentary behaviour (total sedentary time, number of breaks) under free-living conditions. Fifty healthy workers wore the three monitors simultaneously during their waking hours on two days, including a work day and a non-work day. Valid data were at least 10 hours of wearing time, and the differences between monitors on the sedentary outputs using the AP as criterion measurement were analyzed by ANOVA. The number of participants who had complete valid data for work day and non-work day was 47 and 44, respectively. Total sedentary time and breaks estimated by the AP were respectively 466.5 ± 146.8 min and 64.3 ± 24.9 times on the work day and 497.7 ± 138.3 min and 44.6 ± 15.4 times on the non-work day. In total sedentary time, the ASP estimated 29.7 min (95%CI = 7.9 to 51.5) significantly shorter than the AP on the work day but showed no significant difference against the AP on the non-work day. The GT3X+ estimated 80.1 min (54.6 to 105.6) and 52.3 (26.4 to 78.2) significantly longer than the AP on the work day and the non-work day, respectively. For the number of breaks from sedentary time, on both days, the ASP and the GT3X+ estimated significantly more than the AP: 14.1 to 15.8 times (6.3 to 22.5) for the ASP and 27.7 to 28.8 times (21.8 to 34.8) for the GT3X+. Compared to the AP as the criterion, the ASP can underestimate total sedentary time and the GT3X+ can overestimate it, and more so at the lower levels of sedentary time. For breaks from sedentary time, compared to the AP, both the GT3X+ the ASP can overestimate.

Breaking Up Sitting with Light-Intensity Physical Activity: Implications for Shift-Workers

Prolonged sitting, restricted sleep, and circadian disruption are all independent risk factors for non-communicable diseases. Previous research has demonstrated that breaking up sitting with light-intensity physical activity has clear benefits for the health of day workers, but these findings may not apply in the presence of sleep restriction and/or circadian disruption-both of which are commonly experienced by shift-workers. Specifically, sleep restriction, and circadian disruption result in acute physiological changes that may offset the benefits of breaking up sitting. This commentary will explore the potential benefits of breaking up sitting for health, work performance, and subsequent sleep in shift-workers. Future areas of research designed to understand the mechanisms by which prolonged sitting and shift work impact worker health and safety and to support the design of effective occupational health and safety interventions are proposed.

Feasibility of a real-time self-monitoring device for sitting less and moving more: a randomised controlled trial

OBJECTIVES

Time spent inactive and sedentary are both associated with poor health. Self-monitoring of walking, using pedometers for real-time feedback, is effective at increasing physical activity. This study evaluated the feasibility of a new pocket-worn sedentary time and physical activity real-time self-monitoring device (SitFIT).

METHODS

Forty sedentary men were equally randomised into two intervention groups. For 4 weeks, one group received a SitFIT providing feedback on steps and time spent sedentary (lying/sitting); the other group received a SitFIT providing feedback on steps and time spent upright (standing/stepping). Change in sedentary time, standing time, stepping time and step count was assessed using activPAL monitors at baseline, 4-week follow-up (T1) and 12-week (T2) follow-up. Semistructured interviews were conducted after 4 and 12 weeks.

RESULTS

The SitFIT was reported as acceptable and usable and seen as a motivating tool to reduce sedentary time by both groups. On average, participants reduced their sedentary time by 7.8 minutes/day (95% CI -55.4 to 39.7) (T1) and by 8.2 minutes/day (95% CI -60.1 to 44.3) (T2). They increased standing time by 23.2 minutes/day (95% CI 4.0 to 42.5) (T1) and 16.2 minutes/day (95% CI -13.9 to 46.2) (T2). Stepping time was increased by 8.5 minutes/day (95% CI 0.9 to 16.0) (T1) and 9.0 minutes/day (95% CI 0.5 to 17.5) (T2). There were no between-group differences at either follow-up time points.

CONCLUSION

The SitFIT was perceived as a useful tool for self-monitoring of sedentary time. It has potential as a real-time self-monitoring device to reduce sedentary and increase upright time.

Patterns of sedentary time and ambulatory physical activity in a Danish population of girls and women with Rett syndrome

BACKGROUND

Rett syndrome (RTT) is a rare neurodevelopmental disorder leading to multiple disabilities and high dependency on caregivers. This study aimed to: (1) describe the patterns of sedentary time and daily steps and (2) identify the association of individual and environmental characteristics with sedentary time.

METHODS

All Danish females with RTT older than 5 years of age and with a MECP2 mutation were invited to participate. The activPAL and StepWatch Activity Monitor (SAM) were worn by participants for at least four days. Sedentary time and step counts were plotted by time to examine daily activity patterns. Associations between sedentary time and individual and environmental covariates were assessed with linear regression models.

RESULTS

The median (interquartile range) age of participants was 22.0 (14.3-36.5) years. On average 83.3% (standard deviation 13.9%) of waking hours were spent in sedentary behaviours (n = 48) and the median (interquartile range) daily step count was 5128 (2829-7704) (n = 28). Females older than 33.5 years, and those unable to walk independently were more sedentary.

CONCLUSIONS

This study demonstrated high levels of sedentary time and low daily step counts in a Danish population of females with RTT. Advancing age and lower walking skills were associated with higher levels of sedentary time. Implications for Rehabilitation Sedentary lifestyles in individuals with disabilities have a negative impact on health and quality of life. High levels of sedentary time and low daily step counts were demonstrated in a Danish population of females with Rett syndrome. Advancing age and inability to walk independently were strongly associated with higher levels of sedentary time in females with Rett syndrome. Understanding patterns of sedentary behaviour and physical activity can aid health care professionals in developing health-promoting physical activity interventions.

[Evaluation of Worker's Living Activity-time Questionnaire (JNIOSH-WLAQ) primarily to assess workers' sedentary behavior]

OBJECTIVES

The National Institute of Occupational Safety and Health, Japan (JNIOSH) developed a new Worker's Living Activity-time Questionnaire (JNIOSH-WLAQ) which primarily evaluates workers' sedentary behavior. The purpose of this study was to investigate the test-retest reliability and criterion validity of the WLAQ.

METHODS

One hundred and thirty eight workers completed the WLAQ twice in one week. During the week, they wore a thigh-worn inclinometer (activPAL) and maintained a daily log as criteria measurements. The WLAQ measures working time, commuting time, daily rest period (DRP), sleeping time, and time spent sitting within the four typical domains of a worker's life: (a) working time, (b) commuting time, (c) non-working time on a workday, and (d) non-workday. We calculated intraclass correlation coefficients (ICC) as a reliability value and Spearman's ρ as a validity value. Bland-Altman plots were used to assess any bias.

RESULTS

The analysis of WLAQ indicated favorable ICCs (0.72-0.98) for all living activity-times. The WLAQ had "strong" ρ values for working time (0.80) and DRP (0.83), a "very strong" ρ value for commuting time (0.96), and "moderate" ρ values for sleeping time during a workday (0.69) and a non-workday (0.53). As for the sitting time, the WLAQ had "moderate" ρ values for working time (0.67) and non-working time on a workday (0.59), a "strong" ρ value for commuting time (0.82), and a "low" ρ value for a non-workday (0.40). Bland-Altman plots showed a significant fixed bias for sitting time during working time and significant fixed and proportional biases for sitting time on a non-workday.

CONCLUSIONS

The study showed that the WLAQ has acceptable measurement features, which makes this questionnaire a reliable resource for future epidemiological surveys.

Comparison of Sedentary Estimates between activPAL and Hip- and Wrist-Worn ActiGraph

PURPOSE

Sedentary behavior is an emerging independent health risk factor. The accuracy of measuring sedentary time using accelerometers may depend on the wear location. This study in older adults evaluated the accuracy of various hip- and wrist-worn ActiGraph accelerometer cutoff points to define sedentary time using the activPAL as the reference method.

METHODS

Data from 62 adults (mean age, 78.4 yr) of the Aging Research Evaluating Accelerometry study were used. Participants simultaneously wore an activPAL accelerometer on the thigh and ActiGraph accelerometers on the hip, dominant, and nondominant wrist for 7 d in a free-living environment. Using the activPAL as the reference criteria, we compared classification of sedentary time to hip-worn and wrist-worn ActiGraph accelerometers over a range of cutoff points for both 60-s and 15-s epochs.

RESULTS

The optimal cutoff point for the hip vertical axis was <22 counts per minute with an area under the curve (AUC) of 0.85; the optimal hip vector magnitude cutoff point was <174 counts per minute with an AUC of 0.89. For the dominant wrist, the optimal vector magnitude cutoff point to define sedentary time was <2303 counts per minute (AUC, 0.86) and for the nondominant wrist <1853 counts per minute (AUC, 0.86). The optimal 15-s cutoff points resulted in lower agreements compared with activPAL.

CONCLUSIONS

Hip- and wrist-worn ActiGraph data may be used to define sedentary time with a moderate to high accuracy when compared with activPAL. The observed optimal cutoff point for hip vertical axis <22 counts per minute is substantially lower than the standard <100 counts per minute. It is unknown how these optimal cutoff points perform in different populations. Results on an individual basis should therefore be interpreted with caution.

Sit to stand activity during stroke rehabilitation

Objectives The sit to stand (STS) movement is key to independence and commonly affected by stroke. Repetitive practice is likely to improve STS ability during rehabilitation, however current practice levels are unknown. The objective of this study was simply to count the number of STS movements performed during the rehabilitation period of stroke patients using a physical activity monitor (PAM) and test whether being observed altered outcome. Methods Participants were medically stable patients referred for rehabilitation following stroke. Participants were randomly allocated to either wear or not wear the PAM for 14 days. STS ability and general mobility were recorded before and after. Results Sixty-one patients was recruited; aged 68.4 ± 13.15 years, weight 77.12 ± 22.73 Kg, Height 1.67 ± 0.1 m, within 9 ± 9 days of their stroke and an NIHSS score of 6.4 ± 3.3. The monitored group (n = 38) performed 25.00 ± 17.24 daily STS movements. Those requiring assistance achieved 14.29 ± 16.10 per day while those independent in the movement achieved 34.10 ± 12.44. There was an overall improvement in mobility (p = 0.002) but not STS performance (p = 0.053) neither outcome was affected by group allocation (p = 0.158). Cognition and mobility at baseline explained around 50% of daily STS variability. Discussion Low levels of STS activity were recorded during the rehabilitation period of stroke patient. The mean daily STS activity was lower than reports for frail older people receiving rehabilitation, and substantially below levels recorded by community living older adults. STS repetitions may represent general physical activity and these low levels support previous reports of sedentary behavior during rehabilitation.

Sedentary Behaviors and Biomarkers Among Breast Cancer Survivors

BACKGROUND

Sedentary behavior is associated with increased risk of poor outcomes in breast cancer survivors, but underlying mechanisms are not well understood. This pilot study explored associations between different aspects of sedentary behaviors (sitting, prolonged sitting, sit-to-stand transitions, and standing) and breast cancer risk-related biomarkers in breast cancer survivors (n = 30).

METHODS

Sedentary behavior variables were objectively measured with thigh-worn activPALs. Breast cancer risk-related biomarkers assessed were C-reactive protein (CRP), insulin, and homeostatic model assessment of insulin resistance (HOMA-IR) and were measured in fasting plasma samples. Linear regression models were used to investigate associations between sedentary behavior variables and biomarkers (log CRP, insulin, and HOMA-IR).

RESULTS

Sit-to-stand transitions were significantly associated with insulin resistance biomarkers (P < .05). Specifically, each 10 additional sit-to-stand transitions per day was associated with a lower fasting insulin concentration (β = -5.52; 95% CI, -9.79 to -1.24) and a lower HOMA-IR value (β = -0.22; 95% CI, -0.42 to -0.03). Sit-to-stand transitions were not significantly associated with CRP concentration (P = .08). Total sitting time, long sitting bouts, and standing time were not significantly associated with CRP, insulin, or HOMA-IR (P > .05).

CONCLUSIONS

Sit-to-stand transitions may be an intervention target for reducing insulin resistance in breast cancer survivors, which may have favorable downstream effects on cancer prognosis.

Accuracy of Posture Allocation Algorithms for Thigh- and Waist-Worn Accelerometers

PURPOSE

The objective of this study is to compare the accuracy of the activPAL and ActiGraph GT3X+ (waist and thigh) proprietary postural allocation algorithms and an open-source postural allocation algorithm applied to GENEActiv (thigh) and ActiGraph GT3X+ (thigh) data.

METHODS

Thirty-four adults (≥18 yr) wore the activPAL3, GENEActiv, and ActiGraph GT3X+ on the right thigh and an ActiGraph on the right hip while performing four lying, seven sitting, and five upright activities in the laboratory. Lying and sitting tasks incorporated a range of leg angles (e.g., lying with legs bent and sitting with legs crossed). Each activity was performed for 5 min while being directly observed. The percentage of the time the posture was correctly classified was calculated.

RESULTS

Participants consisted of 14 males and 20 females (mean age, 27.2 ± 5.9 yr; mean body mass index, 23.8 ± 3.7 kg·m). All postural allocation algorithms applied to monitors worn on the thigh correctly classified ≥93% of the time lying, ≥91% of the time sitting, and ≥93% of the time upright. The ActiGraph waist proprietary algorithm correctly classified 72% of the time lying, 58% of the time sitting, and 74% of the time upright. Both the activPAL and ActiGraph thigh proprietary algorithms misclassified sitting on a chair with legs stretched out (58% and 5% classified incorrectly, respectively). The ActiGraph thigh proprietary and open-source algorithm applied to the thigh-worn ActiGraph misclassified participants lying on their back with their legs bent 27% and 9% of the time, respectively.

CONCLUSION

All postural allocation algorithms when applied to devices worn on the thigh were highly accurate in identifying lying, sitting, and upright postures. Given the poor accuracy of the waist algorithm for detecting sitting, caution should be taken if inferring sitting time from a waist-worn device.

Altered right anterior insular connectivity and loss of associated functions in adolescent chronic fatigue syndrome

Impairments in cognition, pain intolerance, and physical inactivity characterize adolescent chronic fatigue syndrome (CFS), yet little is known about its neurobiology. The right dorsal anterior insular (dAI) connectivity of the salience network provides a motivational context to stimuli. In this study, we examined regional functional connectivity (FC) patterns of the right dAI in adolescent CFS patients and healthy participants. Eighteen adolescent patients with CFS and 18 aged-matched healthy adolescent control participants underwent resting-state functional magnetic resonance imaging. The right dAI region of interest was examined in a seed-to-voxel resting-state FC analysis using SPM and CONN toolbox. Relative to healthy adolescents, CFS patients demonstrated reduced FC of the right dAI to the right posterior parietal cortex (PPC) node of the central executive network. The decreased FC of the right dAI–PPC might indicate impaired cognitive control development in adolescent CFS. Immature FC of the right dAI–PPC in patients also lacked associations with three known functional domains: cognition, pain and physical activity, which were observed in the healthy group. These results suggest a distinct biological signature of adolescent CFS and might represent a fundamental role of the dAI in motivated behavior.

Objectively Measured Daily Physical Activity and Postural Changes as Related to Positive and Negative Affect Using Ambulatory Monitoring Assessments

OBJECTIVE

The aim of the study was to determine whether objectively measured daily physical activity and posture of sitting, standing, and sit-to-stand transitions are associated with daily assessments of affect.

METHODS

Participants (N = 51, 49% female) wore ActivPal accelerometers for 24 h/d for seven consecutive days. Time spent sitting, standing, and being physically active and sit-to-stand transitions were derived for each day. Participants also completed a mood inventory each evening. Multilevel models examined within- and between-person associations of daily physical activity with positive and negative affect, adjusting for age, sex, body mass index, education, and sleep duration.

RESULTS

Within-person associations showed that a 1-hour increase in daily physical activity was associated with a decrease in negative affect over the same day (B = -0.11, 95% confidence interval [CI], -0.21 to -0.01). Between-person associations indicated a borderline significant association between higher average daily physical activity levels and higher positive affect (B = 1.85, 95% CI = -0.25 to 3.94). There were no between- or within-person associations between sitting, standing, and sit-to-stand transitions with affect.

CONCLUSIONS

Promoting physical activity may be a potential intervention strategy to acutely suppress negative affective states.