This study investigated temporal changes in movement strategy and performance during fatiguing short-cycle work. Eighteen participants performed six 7-min work blocks with repetitive reaching movements at 0.5 Hz, each followed by a 5.5-min rest break for a total duration of 1 h. Electromyography (EMG) was collected continuously from the upper trapezius muscle, the temporal movement strategy and timing errors were obtained on a cycle-to-cycle basis, and perceived fatigue was rated before and after each work block. Clear signs of fatigue according to subjective ratings and EMG manifestations developed within each work block, as well as during the entire hour. For most participants, timing errors gradually increased, as did the waiting time at the near target. Changes in temporal movement strategy were negatively correlated with changes in the level and variability of EMG, suggesting that an adaptive temporal strategy offset the development of unstable motor solutions in this fatiguing, short-cycle work.Practitioner Summary: Sustained performance of operators is essential to maintain competitiveness. In this study of repetitive work, participants gradually changed their temporal movement strategy, for possibly alleviating the effects of fatigue. This suggests that in order to effectively counteract fatigue and sustain performance, industrial production should allow extensive spatial and temporal flexibility.
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Background: Development of more effective interventions for nonspecific chronic low back pain (LBP), requires a robust theoretical framework regarding mechanisms underlying the persistence of LBP. Altered movement patterns, possibly driven by pain-related cognitions, are assumed to drive pain persistence, but cogent evidence is missing. Aim: To assess variability and stability of lumbar movement patterns, during repetitive seated reaching, in people with and without LBP, and to investigate whether these movement characteristics are associated with painrelated cognitions. Methods: 60 participants were recruited, matched by age and sex (30 back-healthy and 30 with LBP). Mean age was 32.1 years (SD13.4). Mean Oswestry Disability Index-score in LBP-group was 15.7 (SD12.7). Pain-related cognitions were assessed by the ‘Pain Catastrophizing Scale’ (PCS), ‘Pain Anxiety Symptoms Scale’ (PASS) and the task-specific ‘Expected Back Strain’ scale(EBS). Participants performed a seated repetitive reaching movement (45 times), at self-selected speed. Lumbar movement patterns were assessed by an optical motion capture system recording positions of cluster markers, located on the spinous processes of S1 and T8. Movement patterns were characterized by the spatial variability (meanSD) of the lumbar Euler angles: flexion-extension, lateralbending, axial-rotation, temporal variability (CyclSD) and local dynamic stability (LDE). Differences in movement patterns, between people with and without LBP and with high and low levels of pain-related cognitions, were assessed with factorial MANOVA. Results: We found no main effect of LBP on variability and stability, but there was a significant interaction effect of group and EBS. In the LBP-group, participants with high levels of EBS, showed increased MeanSDlateral-bending (p = 0.004, η2 = 0.14), indicating a large effect. MeanSDaxial-rotation approached significance (p = 0.06). Significance: In people with LBP, spatial variability was predicted by the task-specific EBS, but not by the general measures of pain-related cognitions. These results suggest that a high level of EBS is a driver of increased spatial variability, in participants with LBP.
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To evaluate the 5-year course of physical work capacity of participants with early symptomatic osteoarthritis (OA) of the hip and/or the knee; to identify trajectories and explore the relationship between trajectories and covariates. Methods In a prospective cohort study, physical work capacity was measured at baseline, using a test protocol (functional capacity evaluation) consisting of work-related physical activities. Participants were invited to participate in 1, 2 and 5 year follow-up measurements. Multilevel analysis and latent classes analysis were performed, in models with test performances as dependent variables and age, sex, work status, self-reported function (Western Ontario McMasters Arthritis Scale-WOMAC), body mass index (BMI) and time as independent variables. Multiple imputation was used to control for the influence of missing data. Results At baseline and after 1, 2 and 5 years there were 96, 64, 61 and 35 participants. Mean (SD) age at baseline was 56 (4.9) years, 84% were females. There was no statistically significant change in test performances (lifting low and high, carrying, static overhead work, repetitive bending, repetitive rotations) between the 4 measurements. Male sex, younger age and better self-reported function were statistically significant (p < 0.05) determinants of higher performance on most of the tests; having a paid job, BMI and progression of time were not. Three trajectories were identified: 'weak giving way', 'stable and able', and 'strong with decline'. Discussion In subgroups of participants with early symptomatic OA, determined by age, sex and self-reported function, physical work capacity seems to be a stable characteristic over 5 years.
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Het Nieuwe Werken concept (HNW) kenmerkt zich onder andere door de grote mate van vrijheid voor medewerkers om tijd- en plaatsonafhankelijk te werken. Microsoft Nederland was in 2007 één van de eerste organisaties die dit concept vergaand doorvoerde. Zeven jaar na dato hebben wij onderzoek gedaan naar de mate waarin de vrijheid ten aanzien van werktijden het leef- en werkritme van de medewerkers heeft beïnvloed. Als eerste hebben we een klein kwantitatief onderzoek uitgevoerd om na te gaan in hoeverre medewerkers er nieuwe ritmes op nahielden. Daaruit bleek onder andere dat er op dit gebied geen grote veranderingen hebben plaatsgevonden. Naar aanleiding hiervan hebben we interviews gehouden om te achterhalen welke motieven er spelen bij het vasthouden aan traditionele werktijden. Uit het onderzoek bleek dat medewerkers weliswaar zeer tevreden zijn met de geboden vrijheid, maar dat verbindende factoren als familie, klanten en collega’s belangrijke factoren zijn bij het handhaven van een traditioneel leef- en werkritme.
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Particulate matter (PM) exposure, amongst others caused by emissions and industrial processes, is an important source of respiratory and cardiovascular diseases. There are situations in which blue-collar workers in roadwork companies are at risk. This study investigated perceptions of risk and mitigation of employees in roadwork (construction and maintenance) companies concerning PM, as well as their views on methods to empower safety behavior, by means of a mental models approach. We held semi-structured interviews with twenty-two employees (three safety specialists, seven site managers and twelve blue-collar workers) in three different roadwork companies. We found that most workers are aware of the existence of PM and reduction methods, but that their knowledge about PM itself appears to be fragmented and incomplete. Moreover, road workers do not protect themselves consistently against PM. To improve safety instructions, we recommend focusing on health effects, reduction methods and the rationale behind them, and keeping workers’ mental models into account. We also recommend a healthy dialogue about work-related risk within the company hierarchy, to alleviate both information-related and motivation-related safety issues. https://doi.org/10.1016/j.ssci.2019.06.043 LinkedIn: https://www.linkedin.com/in/john-bolte-0856134/
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Workers are an important factor in the implementation of a construction project. Applying ergonomic postures for workers in the projects is necessary to minimize the risk of work accidents and the risk of experiencing musculoskeletal disorders (MsDs). The use of lightweight brick for wall construction is relatively new and is in great demand by construction industries in Indonesia. During wall construction, workers do repetitive activities such as bending, kneeling, holding tools, or tilting the body. These activities potentially increase the risk of injury and musculoskeletal disorders. This study aims to assess the work posture of workers on the wall construction using lightweight brick and to analyze the high-risk activities. The wall construction work assessment included five stages of activities, (1) material transfer, (2) practical columns making and installation, (3) lightweight brick adhesive dough-making process, (4) lightweight bricks laying, and (5) lightweight brick plaster. The Rapid Upper Limb Assessment (RULA) method was used to evaluate the working posture. This method was developed to investigate the risk of abnormalities that workers will potentially experience. Based on the RULA employee assessment worksheet, the research results showed that 69% of workers have a high-risk level of work posture and 31% have low-risk levels of work posture. There are three activities with a high-risk level, namely, material transfer, lightweight brick laying, and lightweight brick plaster. At the same time, practical column making and installation work and lightweight brick adhesive dough-making processes are at a low-risk level. According to the RULA risk level, action is required to investigate and immediately improve activities with a high-risk level. If workers continue to work with the same posture, they will be at risk of developing musculoskeletal disorders related to the neck, trunk, and wrists in the near future. Correcting the worker’s posture can be done by improving work position, process, and workplace layout.
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Introduction Negative pain-related cognitions are associated with persistence of low-back pain (LBP), but the mechanism underlying this association is not well understood. We propose that negative pain-related cognitions determine how threatening a motor task will be perceived, which in turn will affect how lumbar movements are performed, possibly with negative long-term effects on pain. Objective To assess the effect of postural threat on lumbar movement patterns in people with and without LBP, and to investigate whether this effect is associated with task-specific pain-related cognitions. Methods 30 back-healthy participants and 30 participants with LBP performed consecutive two trials of a seated repetitive reaching movement (45 times). During the first trial participants were threatened with mechanical perturbations, during the second trial participants were informed that the trial would be unperturbed. Movement patterns were characterized by temporal variability (CyclSD), local dynamic stability (LDE) and spatial variability (meanSD) of the relative lumbar Euler angles. Pain-related cognition was assessed with the task-specific ‘Expected Back Strain’-scale (EBS). A three-way mixed Manova was used to assess the effect of Threat, Group (LBP vs control) and EBS (above vs below median) on lumbar movement patterns. Results We found a main effect of threat on lumbar movement patterns. In the threat-condition, participants showed increased variability (MeanSDflexion-extension, p<0.000, η2 = 0.26; CyclSD, p = 0.003, η2 = 0.14) and decreased stability (LDE, p = 0.004, η2 = 0.14), indicating large effects of postural threat. Conclusion Postural threat increased variability and decreased stability of lumbar movements, regardless of group or EBS. These results suggest that perceived postural threat may underlie changes in motor behavior in patients with LBP. Since LBP is likely to impose such a threat, this could be a driver of changes in motor behavior in patients with LBP, as also supported by the higher spatial variability in the group with LBP and higher EBS in the reference condition.
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From the article: Abstract. This exploratory and conceptual article sets out to research what arguments and possibilities for experimentation in construction exists and if experimentation can contribute towards more innovative construction as a whole. Traditional, -western- construction is very conservative and regional, often following a traditional and linear design process, which focuses on front-loaded cost savings and repetitive efficiency, rather than securing market position through innovation. Thus becoming a hindrance for the development of the sector as a whole. Exploring the effects of using the, in other design-sectors commonly and successfully practiced, “four-phased iterative method” in architectural construction could be the start of transforming the conservative construction industry towards a more innovative construction industry. The goal of this research is to find whether the proposed strategy would indeed result in a higher learning curve and more innovation during the - architectural- process. Preliminary research indicates that there is argumentation for a more experimental approach to construction.
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This paper presents work aimed at improved organization and performance of production in housing renovation projects. The purpose is to explore and demonstrate the potential of lean work organization and industrialized product technology to improve workflow and productive time. The research included selected case studies that have been found to implement lean work organization and industrialized product technology in an experimental setting. Adjustments to the work organization and construction technology have been implemented on site. The effects of the adjustments have been measured and were reviewed with operatives and managers. The data have been collected and analyzed, in comparison to traditional settings. Two projects were studied. The first case implied am application of lean work organization in which labor was reorganized redistributing and balancing operations among operatives of different trades. In the second case industrialized solution for prefabricated installation of prefabricated roofs. In both cases the labor productivity increased substantially compared to traditional situations. Although the limited number of cases, both situations appeared to be representative for other housing projects. This has led to conclusions extrapolated from both cases applicable to other projects, and contribution to the knowledge to improve production in construction. Vrijhoef, R. (2016). “Effects of Lean Work Organization and Industrialization on Workflow and Productive Time in Housing Renovation Projects.” In: Proc. 24 th Ann. Conf. of the Int’l. Group for Lean Construction, Boston, MA, USA, sect.2 pp. 63–72. Available at: .
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CC-BY Applied Ergonomics, 2021, March https://www.journals.elsevier.com/applied-ergonomics Purpose: To analyze progression of changes in kinematics and work physiology during progressive lifting in healthy adults.Methods: Healthy participants were recruited. A standardized lifting test from the WorkWell Functional Capacity Evaluation (FCE) was administered, with five progressive lifting low series of five repetitions. The criteria of the WorkWell observation protocol were studied: changes in muscle use (EMG), heart rate (heart rate monitor), base of support, posture and movement pattern (motion capture system). Repeated measures ANOVA’s were used to analyze changes during progressive workloads.Results: 18 healthy young adults participated (8 men, 10 women; mean age 22 years). Mean maximum weight lifted was 66 (±3.2) and 44 (±7.4) kg for men and women, respectively. With progressive loads, statistically significant (p < 0.01) differences were observed: increase in secondary muscle use at moderate lifting, increase of heart rate, increase of base of support and movement pattern changes were observed; differences in posture were not significant.Conclusions: Changes in 4 out of 5 kinematic and work physiology parameters were objectively quantified using lab technology during progressive lifting in healthy adults. These changes appear in line with existing observation criteria.
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