Effect of alternating postures on cognitive performance for healthy people performing sedentary work

Prolonged sitting is a risk factor for several diseases and the prevalence of worksite-based interventions such as sit-to-stand workstations is increasing. Although their impact on sedentary behaviour has been regularly investigated, the effect of working in alternating body postures on cognitive performance is unclear. To address this uncertainty, 45 students participated in a two-arm, randomised controlled cross-over trial under laboratory conditions. Subjects executed validated cognitive tests (working speed, reaction time, concentration performance) either in sitting or alternating working postures on two separate days (ClinicalTrials.gov Identifier: NCT02863731). MANOVA results showed no significant difference in cognitive performance between trials executed in alternating, standing or sitting postures. Perceived workload did not differ between sitting and alternating days. Repeated measures ANOVA revealed significant learning effects regarding concentration performance and working speed for both days. These results suggest that working posture did not affect cognitive performance in the short term.

Practitioner Summary: Prior reports indicated health-related benefits based on alternated (sit/stand) body postures. Nevertheless, their effect on cognitive performance is unknown. This randomised controlled trial showed that working in alternating body postures did not influence reaction time, concentration performance, working speed or workload perception in the short term.     

Are hybrid sit–stand postures a good compromise between sitting and standing?

Potential alternatives for conventional sitting and standing postures are hybrid sit-stand postures (i.e. perching). The purposes of this study were (i) to identify where lumbopelvic and pelvic angles deviate from sitting and standing and (ii) to use these breakpoints to define three distinct postural phases: sitting, perching, and standing, in order to examine differences in muscle activations and ground reaction forces between phases. Twenty-four participants completed 19 1-min static trials, from sitting (90°) to standing (180°), sequentially in 5°trunk–thigh angle increments. The perching phase was determined to be 145–175° for males and 160–175° for females. For both sexes, knee extensor activity was lower in standing compared to perching or sitting (p < .01). Anterior–posterior forces were the highest in perching (p < .001), requiring ～15% of body-weight. Chair designs aimed at reducing the lower limb demands within 115–170° trunk–thigh angle may improve the feasibility of sustaining the perched posture.

Practitioner summary: Individuals who develop low back pain in sitting or standing may benefit from hybrid sit-stand postures (perching), yet kinematic and kinetic changes associated with these postures have not been investigated. Perching can improve lumbar posture at a cost of increased lower limb demands, suggesting potential avenues for chair design improvement.

Abbreviations: A/P: anterior-posterior; M/L: medial-lateral; LBP: low back pain; EMG: electromyography; TES: thoracic erector spinae; LES: lumbar erector spinae; VMO: vastus medialis obliquus; MVC: maximum voluntary contraction; ASIS: anterior superior iliac spine; PSIS: posterior superior iliac spine; BW: body weight; RMSE: root mean square error; SD: standard deviation; ROM: range of motion     

A comparison of trunk biomechanics,musculoskeletal discomfort and productivity during simulated sit-stand office work

Sedentary office work has been shown to cause low back discomfort and potentially cause injury. Prolonged standing work has been shown to cause discomfort. The implementation of a sit–stand paradigm is hypothesised to mitigate discomfort and prevent injury induced by prolonged exposure to each posture in isolation. This study explored the potential of sit–stand to reduce discomfort and prevent injury, without adversely affecting productivity. Twenty-four participants performed simulated office work in three different conditions: sitting, standing and sit–stand. Variables measured included: perceived discomfort, L4–L5 joint loading and typing/mousing productivity. Working in a sit–stand paradigm was found to have the potential to reduce discomfort when compared to working in a sitting or standing only configuration. Sit–stand was found to be associated with reduced lumbar flexion during sitting compared to sitting only. Increasing lumbar flexion during prolonged sitting is a known injury mechanism. Therefore, sit–stand exhibited a potentially beneficial response of reduced lumbar flexion that could have the potential to prevent injury. Sit–stand had no significant effect on productivity.

Practitioner Summary: This study has contributed foundational elements to guide usage recommendations for sit–stand workstations. The sit–stand paradigm can reduce discomfort; however, working in a sit–stand ratio of 15:5 min may not be the most effective ratio. More frequent posture switches may be necessary to realise the full benefit of sit–stand.     

Medium-term effects of a two-desk sit/stand workstation on cognitive performance and workload for healthy people performing sedentary work: a secondary analysis of a randomised controlled trial

Implementing sit/stand workstations in sedentary work environments is a common way to reduce sedentary time, but their medium-term effect on cognitive performance is unclear. To address this circumstance, eighteen office workers participated in a two-arm, randomised controlled cross-over trial (ClinicalTrials.gov Identifier: NCT02825303), either working at a traditional (sit) or an interventional (sit/stand) workplace for 23 weeks. Cognitive performance (working speed, reaction time, concentration performance, accuracy), workload and relevant covariates (salivary cortisol level, heart rate, physical activity, sitting time) were measured pre- and post-intervention under laboratory conditions. MANOVA and RMANOVA results did not show differences in performance parameters and workload, respectively, between sit/stand and traditional workplace users. Differences in text editing accuracy and cortisol levels for sit/stand workstation users indicate potential connectivity to cognitive parameters which should be further examined with large-scale studies. Practitioner summary: Medium-term effects of working at sit/stand workstations on cognitive performance and workload are unexplored. This randomised controlled trial suggests that cognitive performance and workload are unaffected for sit/stand workstation users after 23?weeks of use. However, accuracy appeared to improve and physiological stress appeared to be altered.

Abbreviations: BMI: body mass index; IPAQ: International physical activity questionnaire; MET: metabolic equivalent of task; MANOVA: multivariate ANOVA; NASA TLX: NASA task load index; RMANOVA: repeated measures ANOVA     

An investigation into four different sit–stand workstation use schedules

Twelve office workers participated in a study investigating effects of four sit/stand schedules (90-min sit/30-min stand, 80/40, 105/15, and 60/60) via several objective and subjective measures (muscle fatigue, foot swelling, spinal shrinkage, and self-reported discomfort). Results showed that there were no significant differences in shoulder and low back static muscle activities between sitting and standing. Muscle fatigue was developed during workday under all schedules. The longest standing schedule seemed to have a tendency of reducing muscle fatigue. None of the schedules helped or worsened foot swelling and spinal shrinkage. More active break-time activities seemed reducing muscle fatigue and foot swelling. While the self-reported bodily discomfort levels were generally low, the preferred schedules among the participants were varied, although the least standing schedule was the least preferred. We may conclude that effects of using sit–stand workstation to improve musculoskeletal health may be limited but promoting more active break-time activities can help.

Practitioner Summary: Sit–stand workstations are used to reduce work-related musculoskeletal disorders. This study shows that office workers prefer sit/stand durations in the range between 1:1 and 3:1. Longer standing may have the potential to reduce muscle fatigue. However, active break-time activities may be more effective in reducing muscle fatigue and foot swelling.     

A detailed description of the short-term musculoskeletal and cognitive effects of prolonged standing for office computer work

Due to concerns about excessive sedentary exposure for office workers, alternate work positions such as standing are being trialled. However, prolonged standing may have health and productivity impacts, which this study assessed. Twenty adult participants undertook two hours of laboratory-based standing computer work to investigate changes in discomfort and cognitive function, along with muscle fatigue, movement, lower limb swelling and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.47[1.36–1.59]). Sustained attention reaction time (β = 18.25[8.00–28.51]) deteriorated, while creative problem solving improved (β = 0.89[0.29–1.49]). There was no change in erector spinae, rectus femoris, biceps femoris or tibialis anterior muscle fatigue; low back angle changed towards less lordosis, pelvis movement increased, lower limb swelling increased and mental state decreased. Body discomfort was positively correlated with mental state. The observed changes suggest replacing office work sitting with standing should be done with caution.

Practitioner Summary: Standing is being used to replace sitting by office workers; however, there are health risks associated with prolonged standing. In a laboratory study involving 2 h prolonged standing discomfort increased (all body areas), reaction time and mental state deteriorated while creative problem-solving improved. Prolonged standing should be undertaken with caution.     

Biomechanical investigation of prolonged driving in an ergonomically designed truck seat prototype

A postural evaluation during a prolonged driving task was conducted to determine the ergonomic validity of a new freely adjustable truck seat prototype. Twenty participants were recruited to perform two 2-h simulated driving sessions. Postures were assessed using motion capture, accelerometers and pressure pads. Subjective discomfort was also monitored in 15-min increments using ratings of perceived discomfort (RPD) and the Automotive Seating Discomfort Questionnaire. Participants had a more neutral spine posture during the first hour of the drive and reported lower RPDs while sitting in the prototype. Pairing the gluteal backrest panel with the adjustable seat pan helped reduce the average sitting pressure. The industry-standard truck seat may lead to the development of poor whole body posture, and the proposed ergonomic redesign of a new truck seat helped improve sitting posture and reduce perceived discomfort.

Practitioner Summary: A new freely adjustable truck seat prototype was compared to an Industry standard seat to assess hypothesised improvements to sitting posture and discomfort for long haul driving. It was found that the adjustable panels in the prototype helped promote spine posture, reduce sitting pressure and improved discomfort ratings.     

DISCRETE EVENT-DYNAMIC SYSTEMS FOR MODELING DYNAMIC VALUED NETS

The last few years have seen the development of Discrete Event-Dynamic Net Systems^1,2 as instruments for modeling complex systems. They are able to achieve the following objectives:

—formality of the modeling methodology

—ability to model static and dynamic aspects

—ability to pass between levels of differently rich structures by morphisms

—uniform representation of the communication process as

—an information process

—a decision process and

—a control process

—homogeneity of the representation and modeling methods

—ability to derive qualitative and quantitative statements.

The foundation is provided by a Discrete Event-Dynamic Net System which includes the axiomatic declaration of general Petri nets. In order to calculate the structural and dynamic aspects, so-called Petri net machines are developed. It is shown that this approach can even be used to treat the following aspects:

—use of time during the process

—increase of costs during the generation and transportation of information

—augmentation, evaluation and transformation of information objects.

Recursive formulas are derived and some examples calculated.     

Associations of office workers’ objectively assessed occupational sitting,standing and stepping time with musculoskeletal symptoms

We examined the association of musculoskeletal symptoms (MSS) with workplace sitting, standing and stepping time, as well as sitting and standing time accumulation (i.e. usual bout duration of these activities), measured objectively with the activPAL3 monitor. Using baseline data from the Stand Up Victoria trial (216 office workers, 14 workplaces), cross-sectional associations of occupational activities with self-reported MSS (low-back, upper and lower extremity symptoms in the last three months) were examined using probit regression, correcting for clustering and adjusting for confounders. Sitting bout duration was significantly (p < 0.05) associated, non-linearly, with MSS, such that those in the middle tertile displayed the highest prevalence of upper extremity symptoms. Other associations were non-significant but sometimes involved large differences in symptom prevalence (e.g. 38%) by activity. Though causation is unclear, these non-linear associations suggest that sitting and its alternatives (i.e. standing and stepping) interact with MSS and this should be considered when designing safe work systems.

Practitioner summary: We studied associations of objectively assessed occupational activities with musculoskeletal symptoms in office workers. Workers who accumulated longer sitting bouts reported fewer upper extremity symptoms. Total activity duration was not significantly associated with musculoskeletal symptoms. We underline the importance of considering total volumes and patterns of activity time in musculoskeletal research.     

The Proactive and Preventive Privacy (3P) Framework for IoT Privacy by Design

The Problem

Internet of Things (IoT) is providing new services and insights by sensing contextual data but there are growing concerns of privacy risks from users that need immediate attention.

The Reason

The IoT devices and smart services can capture Personally Identifiable Information (PII) without user knowledge or consent. The IoT technology has not reached the desired level of maturity to standardize security and privacy requirements.

The Solution

IoT Privacy by Design is a user-centric approach for enabling privacy with security and safety as a ‘win-win’ positive outcome of IoT offerings, irrespective of business domain. The Proactive and Preventive Privacy (3P) Framework proposed in this paper should be adopted by the IoT stakeholders for building trust and confidence in end users about IoT devices and smart services.     

Notifications Efficiency,Impact, and Interference in Second-Screen Scenarios

The growing use of second-screen devices stresses the importance of finding a balance between engagement, distraction, and disturbance of its users, while simultaneously watching television. In this framework, this article reports on a study designed to analyze the efficiency, impact, and interference of different notification strategies aiming to identify the best approach to be used when an alert is needed in second-screen scenarios.

A prototype able to deliver synchronized information related with TV content, with intervals of 10, 30 and 60 s, followed by individual or combined notifications (e.g., audio, visual, and haptic—on the tablet and visual—on the TV) was developed. A laboratory adapted to replicate a living room was set up and a test that involved watching three segments of a 20-min clip while using the prototype was carried with 30 participants, under a cognitive walk-through protocol.

Quantitative and qualitative results show that receiving notifications while watching TV is effective in alerting users about new information, despite its inherent cognitive disturbance for the TV viewing experience. It was also possible to highlight that in an HCI perspective, the most suitable strategy for integrating notifications (considering type and cadence) should be based on a combination of a visual notification (displayed only on the TV screen) along with a haptic notification (vibration on the tablet); spaced by an interval of at least 30 s.     

Home is where the head is: a distributed cognition account of personal health information management in the home among those with chronic illness

Managing chronic illness requires personal health information management (PHIM) to be performed by lay individuals. Paramount to understanding the PHIM process is understanding the sociotechnical system in which it frequently occurs: the home environment. We combined distributed cognition theory and the patient work system model to investigate how characteristics of the home interact with the cognitive work of PHIM. We used a 3D virtual reality CAVE that enabled participants who had been diagnosed with diabetes (N = 20) to describe how they would perform PHIM in the home context. We found that PHIM is distinctly cognitive work, and rarely performed ‘in the head’. Rather, features of the physical environment, tasks, people, and tools and technologies present, continuously shape and are shaped by the PHIM process. We suggest that approaches in which the individual (sans context) is considered the relevant unit of analysis overlook the pivotal role of the environment in shaping PHIM.

Practitioner Summary:

We examined how Personal Health Information Management (PHIM) is performed in the homes of diabetic patients. We found that approaches to studying cognition that focus on the individual, to the exclusion of their context, overlook the pivotal role of environmental, social, and technological features in shaping PHIM.     

THEORY OF CYBERNETIC AND INTELLIGENT MACHINE BASED ON LIE COMMUTATORS

Many attempts^{1, 7, 8, 35} have been made to overcome the limit imposed by the Turing Machine³⁴ to realise general mathematical functions and models of (physical) phenomena.

They center around the notion of computability.

In this paper we propose a new definition of computability which lays the foundations for a theory of cybernetic and intelligent machines in which the classical limits imposed by discrete algorithmic procedures are offset by the use of continuous operators on unlimited data. This data is supplied to the machine in a totally parallel mode, as a field or wave.

This theory of machines draws its concepts from category theory, Lie algebras, and general systems theory. It permits the incorporation of intelligent control into the design of the machine as a virtual element. The incorporated control can be realized in many (machine) configurations of which we give three:

a) a quantum mechanical realization appropriate to a possible understanding of the quantum computer and other models of the physical microworld,

b) a stochastic realization based on Kolmogorov-Gabor theory leading to a possible understanding of generalised models of the physical or thermodynamic macroworld, and lastly

c) a classical mechanical realization appropriate lo the study of a new class of robots.

Particular applications at a fundamental level are cited in geometry, mathematics, biology, acoustics, aeronautics, quantum mechanics, general relativity and. Markov chains. The proposed theory therefore opens a new way towards understanding the processes that underlie intelligence.     

A THEORETICAL STUDY ON ADAPTIVE QUALITY CONTROL SYSTEMS

This paper is a study of an adaptive quality control system from a viewpoint of quality goal. The main purpose is to introduce a conceptual framework for setting up quality goals which are in accordance with the external environment and internal capacity of quality control systems. We apply a mathematical general systems approach.

The results of our paper are summarized as follows:

1)As important decision-making in adaptive QCS, the decision-making for estimalion of fitness and examination of attainability are proposed and formalized mathematically.

2)A refinement process is formalized in which models are revised according to the changes of market.

3)Basic steps for setting quality goals are obtained which are based on the above formalization.     

A comfort assessment of existing cervical orthoses

Purpose: Identify location and intensity of discomfort experienced by healthy participants wearing cervical orthoses.

Method: Convenience sample of 34 healthy participants wore Stro II, Philadelphia, Headmaster, and AspenVista^® cervical orthoses for four-hour periods. Participants reported discomfort level (scale 0–6) and location.

Results: Participants reported mean discomfort for all orthoses over the four-hour test between ‘a little discomfort’ and ‘very uncomfortable’ (mean discomfort score = 1.64, SD = 1.50). Seven participants prematurely stopped tests due to pain and six reported maximum discomfort scores. Significant linear increase in discomfort with duration of wear was found for all orthoses. Significantly less discomfort was reported with Stro II than Headmaster and Philadelphia. Age correlated with greater perceived discomfort. Orthoses differed in the location discomfort was experienced.

Conclusion: Existing cervical orthoses cause discomfort influenced by design and duration of wear with orthoses’ design the more significant factor. This work informed the design of a new orthosis and future orthoses developments.

Practitioner Summary: The purpose of this study was to gain greater knowledge about the discomfort caused by wearing of existing neck orthoses in order to inform the design and development of a new neck orthosis. This study gathers empirical data from a surrogate population and concludes that orthosis design is more influential than the duration of wear.     

Distress and worry as mediators in the relationship between psychosocial risks and upper body musculoskeletal complaints in highly automated manufacturing

As a result of changes in manufacturing including an upward trend in automation and the advent of the fourth industrial revolution, the requirement for supervisory monitoring and consequently, cognitive demand has increased in automated manufacturing. The incidence of musculoskeletal disorders has also increased in the manufacturing sector. A model was developed based on survey data to test if distress and worry mediate the relationship between psychosocial factors (job control, cognitive demand, social isolation and skill discretion), stress states and symptoms of upper body musculoskeletal disorders in highly automated manufacturing companies (n = 235). These constructs facilitated the development of a statistically significant model (RMSEA 0.057, TLI 0.924, CFI 0.935). Cognitive demand was shown to be related to higher distress in employees, and distress to a higher incidence of self-reported shoulder and lower back symptoms. The mediation model incorporating stress states (distress, worry) as mediators is a novel approach in linking psychosocial risks to musculoskeletal disorders.

Practitioners’ Summary

With little requirement for physical work in many modern automated manufacturing workplaces, there is often minimal management focus on Work-Related Musculoskeletal Disorders (WRMSDs) as important occupational health problems. Our model provides evidence that psychosocial factors are important risk factors in symptoms of WRMSD and should be managed.     

Push Notifications in Diet Apps: Influencing Engagement Times and Tasks

Background: Smartphones have reached levels of popularity and penetration where they are now suitable for use in population health interventions. A key feature of smartphones is push notification or in app messaging service, which can be used to alert users to messages or instructions pertaining to an installed app. Little evidence exists as to the persuasive power of these messages.

Method: We conducted a 24-week live user evaluation of push notifications used in a behavior-based mobile app for a meal replacement program to understand the role of push notifications in persuading users to engage with self-monitoring tasks.

Results: User perception of the prompts were verified through questionnaires, which in conjunction with the interaction logs show that users were tolerant of multiple daily prompts. The decline in compliance to the tasks set, however, shows that while the participants did not object to receiving prompts, they were less likely to respond to them as the study progressed.

Conclusions: Push notifications and user tasks are appropriate mechanisms to engage users with mobile technology in the short term.     

Evaluation of Three Tablet Computers at Two Levels of Ambient Illumination

Background: Tablet computers are increasingly widespread in this digital era. During tablet computer use, two important factors are display quality and ambient illumination. The purpose of this experiment was to understand the effects of the display quality of tablet computers (a Sony, a Samsung, and an iPad) and ambient illumination levels (200 lx, 500 lx) on visual fatigue, comfort perception, and task performance.

Methods: Thirty-five university students (17 males and 18 females) were recruited for this experiment. They performed six 40-min trials of playing computer games in all experimental conditions. Visual fatigue, comfort perception, and task performance were collected at the end of each trial.

Results and Discussion: There were no interactions between display model and ambient illumination. Display model had a significant effect on visual fatigue and visual performance, and the best display quality caused less visual fatigue during long periods of viewing. We found no significant effect between 200 lx and 500 lx of ambient illumination on visual fatigue or visual performance; therefore, further research should be conducted to determine what levels of ambient illumination, both high and low, can affect visual fatigue and task performance.     

Inter-rater reliability of an observation-based ergonomics assessment checklist for office workers

Objectives: To establish the inter-rater reliability of an observation-based ergonomics assessment checklist for computer workers. Methods: A 37-item (38-item if a laptop was part of the workstation) comprehensive observational ergonomics assessment checklist comparable to government guidelines and up to date with empirical evidence was developed. Two trained practitioners assessed full-time office workers performing their usual computer-based work and evaluated the suitability of workstations used. Practitioners assessed each participant consecutively. The order of assessors was randomised, and the second assessor was blinded to the findings of the first. Unadjusted kappa coefficients between the raters were obtained for the overall checklist and subsections that were formed from question-items relevant to specific workstation equipment. Results: Twenty-seven office workers were recruited. The inter-rater reliability between two trained practitioners achieved moderate to good reliability for all except one checklist component. Conclusions: This checklist has mostly moderate to good reliability between two trained practitioners.

Practitioner Summary: This reliable ergonomics assessment checklist for computer workers was designed using accessible government guidelines and supplemented with up-to-date evidence. Employers in Queensland (Australia) can fulfil legislative requirements by using this reliable checklist to identify and subsequently address potential risk factors for work-related injury to provide a safe working environment.     

The Observer-Generated Information Process: Composite Stages,Cooperative “Logical” Structure,and Self-Organization

Conventional information science generally considers an information process, but traditionally uses the probability measure for random events, and Shannon’s entropy measure as an uncertainty function of the states. The cutting process on separated states decreases quantity information concealed in the states correlation, holding hidden process information.

Up to now, “information process” has not had a scientifically conclusive definition nor its implicit structure.

The presenting information process performs logical operations with discrete information units (Bits) to achieve a goal, integrating the discrete mutually connected sequence of symbols and the extracting process’ hidden information in the structure of an information Observer. The probing time-space observation develops the unit of space-time geometry-memorizing logic.

The defined information process starts generating observations of a random process via the logic of probing impulses, sequentially cutting the process entropy measure and creating the discrete information units whose integration enfolds the information geometrical structure of an Observer. Found composite stages of the information process and the synthesized optimal process trajectory minimize observation time in an artificially designed information Observer with intellectual searching logic. The analytical modeling, computer simulations, and experimental applications validate the results.