The activation of mechanisms linking judgements of work design and management with musculoskeletal pain

The report of work-related musculoskeletal pain may be related to worker evaluations of the design and management of work through two mechanisms: one biomechanical and the other stress-related. This study of engineering workers (n = 204) explored the validity of these mechanisms using sequential logistic regression. Analyses suggested that workers' ratings of the adequacy of the design and management of their work were related to their report of work-related musculoskeletal pain. However, the mechanisms appeared to be activated in certain conditions. The reporting of pain in the upper body was both biomechanically- and stress-related, whereas that in the lower body was only biomechanically-related. It is argued that the mechanism activated appeared to be determined by the anatomical location of the pain, and probably the variance shared between the different aspects of work design and management, on the one hand, and the mechanical load of the job, on the other.     

Hard work at home: musculoskeletal pain among female homemakers

This study explores the relationship between housework and musculoskeletal symptoms among homemakers, adjusting for social, demographic and economic factors. A cross-sectional survey was carried out on 435 women from Nabaa, a low-income community in Lebanon. In total, 77% of women reported having musculoskeletal pain in the previous 12 months. Both psychosocial and physical factors showed significant associations with musculoskeletal symptoms. Related psychosocial factors included feelings of stress associated with homemaking and homemakers' number of children and self-rated health. The physical factors associated with musculoskeletal pain were feeling fatigued at the end of a housework day, working long hours and working in awkward postures or frequently engaging in repetitive hand movements. Ergonomic stressors were also associated with pain in the back and upper and lower extremities. Women from this community engage in a large number of hours of housework that, alongside other factors, were associated with high prevalence of musculoskeletal pain. PRACTITIONER SUMMARY: This study contributes to the literature by studying women's housework activities in association with musculoskeletal pain. The role of women in homemaking activities is explored together with physical exposures leading to reported symptoms. This study adds a perspective of a Middle Eastern context to the literature of women's musculoskeletal health.     

The influence of VDT work on musculoskeletal disorders

Relationships between visual display terminal (VDT) use and musculoskeletal problems were examined in a group of 353 office workers, using data from medical and workplace investigations as well as questionnaires. There were no general differences between VDT and non-VDT users as to the occurrence of muscle problems. Combinations of specific VDT work situations such as data entry work or work with a VDT for more than 20 h/week and the presence of some other factors were, however, associated with excess risks of certain muscle problems. The extraneous factors involved in the definitions of such risk groups were: use of bifocal or progressive glasses at a VDT; stomach-related stress reactions; limited rest break opportunity, repetitive movements; non-use of lower arm support; and possibly the vertical position of the keyboard; and presence of specular glare.     

Flexible workspace design and ergonomics training: impacts on the psychosocial work environment, musculoskeletal health, and work effectiveness among knowledge workers

A macroergonomics intervention consisting of flexible workspace design and ergonomics training was conducted to examine the effects on psychosocial work environment, musculoskeletal health, and work effectiveness in a computer-based office setting. Knowledge workers were assigned to one of four conditions: flexible workspace (n=121), ergonomics training (n=92), flexible workspace+ergonomics training (n=31), and a no-intervention control (n=45). Outcome measures were collected 2 months prior to the intervention and 3 and 6 months post-intervention. Overall, the study results indicated positive, significant effects on the outcome variables for the two intervention groups compared to the control group, including work-related musculoskeletal discomfort, job control, environmental satisfaction, sense of community, ergonomic climate, communication and collaboration, and business process efficiency (time and costs). However, attrition of workers in the ergonomics training condition precluded an evaluation of the effects of this intervention. This study suggests that a macroergonomics intervention is effective among knowledge workers in office settings.     

Evaluation and design of online cooperative feedback mechanisms for reputation management

This research evaluates and analyzes existing mechanisms of online reputation systems based on cooperative feedbacks of past transaction information. We find existing popular feedback systems do not provide sustained incentives for sellers to behave honestly over time. We propose a new design of reputation system based on exponential smoothing. This mechanism is shown to be more robust compared to the existing systems. We relax the assumption of a static product value and have implemented a two-level exponential smoothing policy to process and aggregate reputation information. The simulation results show that the policy can serve as a sustained incentive mechanism for the seller.     

Checkout cashier work and counter design – Video movement analysis, musculoskeletal disorders and customer interaction

This study was conducted in order to analyse checkout cashiers’ movements at a checkout counter during interaction with customers and the prevalence of work-related stress and musculoskeletal disorders in checkout cashiers. In one shop, six cashiers were videotaped during the workday, and 50 cashiers from seven shops from the same chain of stores responded a questionnaire. Cashier activities and movements, customer interaction and counter design issues were analysed from the video data. Prevalence of work-related stress and musculoskeletal disorders was obtained from the questionnaire. It was found that 76% of all items were manually turned or angled. With a better adjustment of the scanner and a standardised positioning of the EAN-code, many of these movements could be avoided. Furthermore the prevalence of musculoskeletal disorders was quite high (68% for the neck). The questionnaire results showed that many cashiers experienced stress, giving a high percentage of cashiers in the “dedication under pressure” group. The behaviour of the customers was the major cause of stress. Other sources of stress arose from bad design or function of the computer system or other technical equipment.

Relevance to industry

In this study several problems regarding cashier work were identified and solutions, relevant to counter and package designers, shop managers and cashiers are suggested. Data obtained on cashier movements and prevalence of musculoskeletal disorders are given.     

The effect of forearm support on musculoskeletal discomfort during call centre work

Using a computer keyboard with the forearms unsupported has been proposed as a causal factor for neck/shoulder and arm/hand diagnoses. Recent laboratory and field studies have demonstrated that forearm support might be preferable to working in the traditional "floating" posture. The aim of this study was to determine whether providing forearm support when using a normal computer workstation would decrease musculoskeletal discomfort in intensive computer users in a call centre. A randomised controlled study (n = 59), of 6 weeks duration was conducted. Thirty participants (Group 1) were allocated to forearm support using the desk surface with the remainder (Group 2) acting as a control group. At 6 weeks, the control group was also set up with forearm support. Both groups were then monitored for another 6 weeks. Questionnaires were used at 1, 6 and 12 weeks to obtain information about discomfort, workstation setup, working posture and comfort. Nine participants (Group 1 n = 6, Group 2 n = 3) withdrew within a week of commencing forearm support either due to discomfort or difficulty in maintaining the posture. At 6 weeks, the group using forearm support generated significantly fewer reports of discomfort in the neck and back, although the difference between the groups was not statistically significant. At 12 weeks, there were fewer reports of neck, back and wrist discomfort when preintervention discomfort was compared with post intervention discomfort. These findings indicate that for the majority of users, forearm support may be preferable to the "floating" posture implicit in current guidelines for computer workstation setup.     

Low back pain in farmers: The association with agricultural work management,disability, and quality of life in Korean farmers

This study aimed to identify the associations among low back pain (LBP), LBP‐related disability, agricultural working condition management, and quality of life (QOL) in Korean farmers. Demographic information, agricultural work management, and outcomes of LBP were obtained by standardized questionnaires (Oswestry Disability Index [ODI] for disability and European Quality of Life‐5 Dimensions‐3‐Level version [EQ‐5D‐3L] for QOL). Presence of LBP was determined if the LBP had lasted longer than 1 week or had been more frequent than once a month, and presence of LBP‐related disability was determined if the ODI score was more than 12. Poor health checkups (OR [odds ratio] = 1.70–86, p < .05), were positively associated with LBP, and working at dawn (OR = 1.85–1.96, p < .05), was positively associated with LBP‐related disability after adjusting related demographic factors. EQ‐5D‐3L indexes were significantly lower in participants with LBP (0.83 ± 0.17 vs. 0.92 ± 0.06, p < .001) and disability (0.81 ± 0.18 vs. 0.93 ± 0.05, p < .001). This study showed that the presence of LBP was related to poor health checkups and that LBP‐related disability was related to a poor working time schedule. These results indicate poor QOL and suggest the need for coping strategies such as regular health checkups and a proper working time schedule.     

Profile of the musculoskeletal pain suffered by textile tufting workers handling thread cones according to work,age and employment duration

Abstract

This paper studies the relationship between some socio-professional characteristics of workers (e.g. age, actual work done, experience in the job, overall time on job market, height) carrying out thread-cone handling tasks and their musculoskeletal pain profiles. Interviews were carried out with foremen and workers, and task analysis was performed. Self-administered questionnaires on work-related pain were filled out by 114 machine operators and creelers in four carpet-manufacturing companies. Statistics on nine individual and 25 pain-symptom characteristics were compiled. For data treatment, two statistical methods complemented one another: the Factorial Analysis of Correspondence (FAC) and the Hierarchical Ascendant Classification (HAC). Four classes of workers showing large differences one to another regarding time of employment on the job market, age, seniority in the company, and job experience were portrayed. No remarkable differences were found between the classes in relation to the proportion of workers showing body pain symptoms; it is greater than 50% in all classes (12 months). Moreover, in all classes, for several workers, the first region of pain (out of three possible) was reported as one persisting over the weekend. The group of workers from 25 to 35 years of age appears to be the one most seriously affected by musculoskeletal pain.     

Reducing whole-body vibration and musculoskeletal injury with a new car seat design

A new car seat design, which allows the back part of the seat (BPS) to lower down while a protruded cushion supports the lumbar spine, was quantitatively tested to determine its effectiveness and potentials in reducing whole-body vibration (WBV) and musculoskeletal disorders in automobile drivers. Nine subjects were tested to drive with the seat in: 1) the conventional seating arrangement (Normal posture); and 2) the new seating design (without BPS (WO-BPS) posture). By reducing contact between the seat and the ischial tuberosities (ITs), the new seating design reduced both contact pressure and amplitude of vibrations transmitted through the body. Root-mean-squared values for acceleration along the z-axis at the lumbar spine and ITs significantly decreased 31.6% (p < 0.01) and 19.8% (p < 0.05), respectively, by using the WO-BPS posture. At the same time, vibration dose values significantly decreased along the z-axis of the lumbar spine and ITs by 43.0% (p < 0.05) and 34.5% (p < 0.01). This reduction in WBV allows more sustained driving than permitted by conventional seating devices, by several hours, before sustaining unacceptable WBV levels. Such seating devices, implemented in large trucks and other high-vibration vehicles, may reduce the risk of WBV-related musculoskeletal disorders among drivers.     

Reducing whole-body vibration and musculoskeletal injury with a new car seat design

A new car seat design, which allows the back part of the seat (BPS) to lower down while a protruded cushion supports the lumbar spine, was quantitatively tested to determine its effectiveness and potentials in reducing whole-body vibration (WBV) and musculoskeletal disorders in automobile drivers. Nine subjects were tested to drive with the seat in: 1) the conventional seating arrangement (Normal posture); and 2) the new seating design (without BPS (WO-BPS) posture). By reducing contact between the seat and the ischial tuberosities (ITs), the new seating design reduced both contact pressure and amplitude of vibrations transmitted through the body. Root-mean-squared values for acceleration along the z-axis at the lumbar spine and ITs significantly decreased 31.6% (p < 0.01) and 19.8% (p < 0.05), respectively, by using the WO-BPS posture. At the same time, vibration dose values significantly decreased along the z-axis of the lumbar spine and ITs by 43.0% (p < 0.05) and 34.5% (p < 0.01). This reduction in WBV allows more sustained driving than permitted by conventional seating devices, by several hours, before sustaining unacceptable WBV levels. Such seating devices, implemented in large trucks and other high-vibration vehicles, may reduce the risk of WBV-related musculoskeletal disorders among drivers.     

Low back pain and other work-related musculoskeletal problems among physiotherapists

This technical note reports the findings of a self-administered questionnaire regarding low back pain (LBP) and other musculoskeletal problems completed by 113 physiotherapists (15% of the active physiotherapists in the Republic of Slovenia). The study revealed that the overall incidence among the sample population of physiotherapists is 73.7% and the most prominent factor appears to be the age of the respondents. The only triggering factor for LBP within the physiotherapy profession appears to be handling of dependent patients.     

Structural design of planar mechanisms with dyads

In this paper, the structural synthesis of planar mechanisms with one, two and three dyads is studied. First a new classification of dyads is introduced and then a new way of constructing mechanisms is explained. The scheme provides a consistent coding scheme for planar mechanisms. The advantage of the classification of a system lies in its simplicity. The solution of the whole system can then be obtained by composing partial solutions. This approach will eliminate the need of storing complete mechanism information in a large database.     

Perceived physical stress at work and musculoskeletal discomfort in X-ray technologists

A structured questionnaire/interview was designed to explore demographic, personal, occupational and occupational health factors as well as recreational physical activities which can affect X-ray technologists' musculoskeletal symptoms. This questionnaire was piloted for clarity and validity. Subsequently, a random sample of 20 volunteer participants (18 female, 2 male) from two University hospitals were administered the questionnaire in the presence of the investigators to ensure that questions were correctly understood. The data obtained were analysed for magnitude, duration and frequency of activities and for severity, duration and recurrence of morbidity. The X-ray technologists in the sample were found to be a young group of professionals ranging from between 20 - 54 years of age. Eighty-nine per cent of the technologists were physically active and 44% indulged in physical recreational activities. Despite the young age and active life style, the X-ray technologists had significant and diverse musculoskeletal problems; 83% of technologists had backache and 39% of the female technologists had neck pain and 28% shoulder pain. The majority of technologists had suffered multiple episodes of pain. Fifty per cent of the female sample and both male volunteers suffered from upper extremity pain.     

Analysis and design of parallel mechanisms with flexure joints

Flexure joints are frequently used in precision-motion stages and microrobotic mechanisms due to their monolithic construction. The joint compliance, however, can affect the static and dynamic performance of the overall mechanism. In this paper, we consider the analysis and design of general platform-type parallel mechanisms containing flexure joints. Based on static performance measures such as task-space stiffness and manipulability, and constraints such as joint stress, mechanism size, and workspace volume, we pose the design problem as a multiobjective optimization. We first calculate the Pareto frontier, which can then be used to select the desired design parameters based on secondary criteria, such as performance sensitivity and dynamic characteristics. To facilitate design iteration, we apply the pseudo rigid-body approach with a lumped approximation of the flexure joints. A planar mechanism is used to illustrate the analysis and design techniques.     

Understanding the link between psychosocial work stressors and work-related musculoskeletal complaints

It is well established that psychosocial work stressors relate to employees' work-related musculoskeletal disorder (WRMSD) symptoms. Using a model investigating psychological strain as a mediator between work stressors and WRMSD complaints, this study demonstrated that high levels role conflict, low job control, and low safety-specific leadership are associated with increased employee strain. Strain, in turn, was related to higher levels of WRMSD symptoms of the wrist/hand, shoulders, and lower back. Partial mediation of some relationships was also found, suggesting that additional meditational mechanisms for the relationships between stressors and musculoskeletal symptoms are plausible. This work supports the notion that psychosocial stressors in the work environment have important links to employee health, especially WRMSDs.     

Perceived physical stress at work and musculoskeletal discomfort in X-ray technologists

A structured questionnaire/interview was designed to explore demographic, personal, occupational and occupational health factors as well as recreational physical activities which can affect X-ray technologists' musculoskeletal symptoms. This questionnaire was piloted for clarity and validity. Subsequently, a random sample of 20 volunteer participants (18 female, 2 male) from two University hospitals were administered the questionnaire in the presence of the investigators to ensure that questions were correctly understood. The data obtained were analysed for magnitude, duration and frequency of activities and for severity, duration and recurrence of morbidity. The X-ray technologists in the sample were found to be a young group of professionals ranging from between 20?–?54 years of age. Eighty-nine per cent of the technologists were physically active and 44% indulged in physical recreational activities. Despite the young age and active life style, the X-ray technologists had significant and diverse musculoskeletal problems; 83% of technologists had backache and 39% of the female technologists had neck pain and 28% shoulder pain. The majority of technologists had suffered multiple episodes of pain. Fifty per cent of the female sample and both male volunteers suffered from upper extremity pain.     

Light as a positive situational cue at work: Satisfaction with light relates to judgements of other's warmth and competence

Abstract

Workplace illumination is known to impact mood, performance and decision-making. Based on the idea that positive feelings associated with light might influence social judgements in workplaces, we propose that satisfaction with light as a specific affective response to light would lead to positive judgements of other individuals. In a laboratory experiment (N?=?164), participants assessed their satisfaction with light and rated other person’s faces on warmth and competence. Results showed that satisfaction with light positively influenced judgement of others. We replicated the positive relation between satisfaction with light and social judgements in a field study with employees (N?=?176). These findings highlight the importance of satisfaction with light for social judgement in workplaces. We discuss theoretical contributions and practical implications concerning the design of settings involving the evaluation of other individuals.

Practitioner Summary: The design of work settings where the evaluation of others takes place is an important topic. A laboratory experiment and a field study demonstrate that satisfaction with workplace illumination influences judgements of others. The results provide interesting possibilities for the design of work settings that involve the evaluation of others.

Abbreviations: ANOVA: Analysis of Variance; ANSI: American National Standards Institute; C: celsius; CI: confidence interval; Cm: centimeter; EN 12464 Lighting of indoor workplaces, English version; IESNA-RP: illuminating engineering society of North America, Recommended Practice; ISO: International Organization for Standardization; K: kelvin; Lx: lux; Min: minutes; PANAS: positive affect and negative affect scale; Ra: colour rendering index; SD: standard deviation; SE: standard error; WMA: World Medical Association     

Similarities between work related musculoskeletal disorders and slips,trips and falls

Most occupational risks manifest themselves through movements performed at work, for example musculoskeletal disorders, slips, trips and falls. Research focusing on such risks often differentiates diseases from accidents. All these risks prove to be diffuse, widespread, emergent and devoid of an external harmful hazard, when analysed through their common vector, i.e. through the movements manifesting them. These characteristics have a strong impact on risk perception and on approaches necessary to ensure sustainable prevention. A participative search for local solutions to preventing these risks, integrating shared risk representation and several analysis levels, would seem helpful. A balance between defended and resilience-based conceptions of health and safety should be established. Research should also be extended to enhance in-depth understanding of controls impacting worker movements when performing a task, while safeguarding health and safety.