A new scoring system for the Rapid Entire Body Assessment (REBA) based on fuzzy sets and Bayesian networks

Traditional methods for assessing the risk of work-related musculoskeletal disorders (WMSDs) have a low sensitivity to changes in input variables. Using them, it is possible to obtain the same risk score for totally different postures, and in some cases, the effectiveness of ergonomic interventions cannot be demonstrated. This study aimed to develop a new scoring system for REBA, FBnREBA, using fuzzy sets and the Bayesian network (BN) approach to cover the drawbacks of the traditional REBA. First, the risk factors of WMSDs were defined in terms of fuzzy membership sets. Next, a BN model was developed based on REBA. Fourteen different postures were assessed using FBnREBA, and the results were compared with those of the original REBA. Lastly, a case study was performed to demonstrate how the new scoring system can be used to rank various interventions based on their effectiveness. FBnREBA is a BN model with 26 nodes and is based completely on REBA, but its results differ from those of REBA for identical postures. A comparison of the results of FBnREBA with those of REBA indicated that FBnREBA is more sensitive to changes in WMSDs risk factors than REBA. A case study was conducted using FBnREBA, and the effectiveness of modifying each body segment was determined and ranked. FBnREBA is more sensitive to changes in input variables so that it is unlikely to obtain the same risk score for different body postures. The introduced methodology can be used to modify the scoring systems of other similar methods.     

Physical and mental workload interactions in a sterile processing department

Work in healthcare facilities has been categorized as a high-risk job for developing Work-Related Musculoskeletal Disorders (WMSDs). Little attention has been given to the Sterile Processing Department (SPD) employees who are exposed to both mentally and physically demanding conditions, factors that may impose an elevated risk in the development of WMSDs. Previous studies have shown that WMSDs can be a result of complex interactions between physical, psychosocial, biological, and individual characteristics. However, the evidence of specific associations is still inconclusive. The objective of this study was to determine if the perception of mental workload causes workers to adopt more risky body postures. The study was carried out in four phases: 1) identification of musculoskeletal disorders using customized Nordic questionnaires, 2) ergonomic assessment of SPD using REBA method, 3) mental workload assessment of SPD using NASA-TLX, and 4) interaction between physical (postural risk) and mental workload through the performance of a task at two different levels of workload conducted through a controlled experiment. The findings indicate that increases in REBA scores and NASA-TLX indices were associated with days and conditions with higher workloads. Results showed evidence that increments on mental workload are related to worsening postures, increasing the risk of developing musculoskeletal disorders. These results serve to raise awareness and warn employees about the need to pause and analyze the way they perform their duties under high levels of workload in an attempt to reduce WMSDs risk in healthcare sector employees.     

Ergonomic risk factors in glass artware industries and prevalence of musculoskeletal disorder

Glass artware manufacturing activities are highly repetitive, labor-intensive, and demand prolonged standing during the working shift. This leads to the development of musculoskeletal disorders (MSDs) symptoms among the workers. However, there is a scarce of study on the prevalence of MSDs symptoms and their associated risk factors among the glass artware workers. To address this research gap, this study aims to evaluate the prevalence of MSDs and working conditions among Indian glass artware workers. Discomfort data is collected using Cornell Musculoskeletal Discomfort Questionnaire and working posture data is collected through direct observations using Rapid Entire Body Assessment (REBA). Multiple logistic regression model is developed for each body region to study the relationship between the associated risk factors and MSDs symptoms with the help of collected data. The findings of this study are first, MSDs symptoms are highly prevalent and severe, particularly in the lower back, thigh, and foot. Second, the average REBA grand score is 7.22, which reveals the high-risk level of worker's posture while performing the task. Third, Job characteristics and individual factors are associated with MSD symptoms in multiple logistic regression models. The results highlight the prevalence and severity level of MSDs and illustrate the demand for ergonomic interventions to alleviate musculoskeletal symptoms among these working groups.Relevance to industryThis study draws attention to work-related and other associated risk factors, which would help the researchers and managers to understand the working environment of glass artware industry. These risk factors should be considered for designing and implementing ergonomic interventions to prevent and alleviate musculoskeletal discomfort among the glass artware workers.     

Paddling upstream: a contextual analysis of implementation of a workplace ergonomic policy at a large newspaper

Efforts to implement workplace ergonomic programs aimed at reducing the burden of work-related musculoskeletal disorders (WMSD) have to address multiple physical and psychosocial aspects of work environments yet often contextual factors limit their success. We describe the processes involved in an ergonomic program to reduce neck and upper limb WMSDs at a large Canadian newspaper. Using qualitative data collection and analysis methods, we illustrate the impact of key contextual characteristics of: (1) the program (management commitment, union involvement, experience and skill of program leaders, and researcher involvement); (2) the organization (drive for productivity, management control, organizational culture); and (3) the broader social context (economic climate, nature of newspaper work, technology and nature of WMSD). We argue for increased attention to identification and response to the contextual factors affecting program implementation in order to more successfully address upstream determinants of WMSD.     

Ergonomic design visualization mapping- developing an assistive model for design activities

Ergonomic models and techniques are a fundamental issue in the design of comfortable and safe products and spaces. User studies, related to visualization tools are current issues in the ergonomics and design visualization literature. But researchers have begun to discover that user study is rarely straightforward, especially when drawing visualization data from interdisciplinary sources. The availability of a plethora of visualization techniques can make it difficult to determine the most appropriate technique to convey maximum possible understanding.The RT-MHV (“Real-time”– “Motion history volumes”) 3D computerized assessment model, developed by the authors, demonstrates a local risk evaluation of work-related musculoskeletal disorders (WMSDs), based on real-time and on motion history volumes. With the model, the visual display of the WMSD risk level for each body segment is defined by color-coding at points surrounding an avatar's segment, representing an actual user. The values associated with areas with an increased risk of WMSDs can be identified and iterated quickly, so as to determine the “optimal posture”. Designers can share this knowledge by recording the user's postural interactions, defined through the mapping of geometric comfort data and WMSD risk level categories.The challenge in the development process was to overcome existing “gaps” between ergonomics data and designer requirements. Further research on the RT-MHV model is recommended, principally for developing stand-alone CAD software. An aggregated statistical information database and complete body joints visualizations will be computerized in due course. 2D tabulation and statistical information relating to body joints will be made available on demand.     

Comparison of ergonomic risk assessment outputs from OWAS and REBA in forestry timber harvesting

Globally, work-related (musculoskeletal disorders (MSDs) are one of the most important health problems encountered by ergonomists. Forest work, especially logging harvesting, is traditionally recognized as one of the most difficult types of physical work and has distinct characteristics. Harvesting works in forestry are composed of the following work stages: logging, skidding, and loading. This study aimed to examine risk factors of MSDs associated with different work postures during harvesting under variable external conditions by comparing work stages using the Ovako Working posture Assessment System (OWAS) and Rapid Entire Body Assessment (REBA). A statistically significant difference was observed between the two methods. While the difference in risk to the musculoskeletal system was statistically significant in different work stages using REBA, logging and skidding were assigned to the same risk level using OWAS. Easy-to-use ergonomic hand tools should be developed that are suitable for working conditions and help reduce MSD risk in forestry workers.     

Assimilation and use of ergonomic knowledge by nonergonomists to improve jobs in two electrical product assembly plants

This article describes the results of an analysis of the assimilation of ergonomic knowledge by nonergonomists during participatory ergonomics projects whose aim is the prevention of work-related musculoskeletal disorders (WMSDs). In two plants producing electrical consumer products and telecommunications equipment, ergonomic groups were established and trained. The groups analyzed seven working situations resulting in 50 implemented proposals. A reduction in WMSD risk factors was observed. The analysis of the assimilation of ergonomic knowledge by the groups and their members was based on two sources: analysis of the groups' working sessions, and independent interviews of group members. The results show that group members master most phases of the formalized ergonomic analysis. The interviews revealed that several factors influence knowledge transfer: prior training and organizational status of the group members, the didactic method used, company culture, support by management, and attitudes of coworkers. © 1997 John Wiley & Sons, Inc.     

Investigative study and sensitivity analysis of Rapid Entire Body Assessment (REBA)

The paper aims primarily to study the sensitivity of Rapid entire body assessment (REBA) and identification of insensitive and sensitive posture zones. The investigative study, and sensitivity analysis of REBA offer deeper insights into the methodology used for the assessment of posture. Full factorial design is divided into parts using a forward approach to access the sensitivity. One parameter is varied keeping other parameters constant to understand its effect on the output score. Combinations of posture where no change was observed were identified. Posture scores were also noted involving sudden jumps. Regression analysis was performed to identify relative importance or weightage of the body and other variables in estimating the final REBA score. The justification of the REBA methodology available in the existing literature is very limited. This paper also demonstrates the need for understanding of REBA method among the researchers. With this paper, ergonomic practitioners can be made aware of insensitive and sensitive zones in posture assessment.OriginalityThis is the first paper that primarily aims to establish the sensitivity of REBA and identifying insensitive postures or problems in REBA assessment. Few research gaps are identified.     

Developing a comprehensive approach to risk management of musculoskeletal disorders in non-nursing health care sector employees

This study of selected jobs in the health care sector explored a range of physical and psychosocial factors to identify those that most strongly predicted work-related musculoskeletal disorders (WMSD) risk. A self-report survey was used to collect data on physical and psychosocial risk factors from employees in three health care organisations in Victoria, Australia. Multivariate analyses demonstrated the importance of both psychosocial and physical hazards in predicting WMSD risk and provides evidence for risk management of WMSDs to incorporate a more comprehensive and integrated approach. Use of a risk management toolkit is recommended to address WMSD risk in the workplace.     

Low back injury risks during construction with prefabricated (panelised) walls: effects of task and design factors

New technology designed to increase productivity in residential construction may exacerbate the risk of work-related musculoskeletal disorders (WMSDs) among residential construction workers. Of interest here are panelised (prefabricated) wall systems (or panels) and facilitating an ongoing effort to provide proactive control of ergonomic exposures and risks among workers using panels. This study, which included 24 participants, estimated WMSD risks using five methods during common panel erection tasks and the influences of panel mass (sheathed vs. unsheathed) and size (wall length). WMSD risks were fairly high overall; e.g. 34% and 77% of trials exceeded the 'action limits' for spinal compressive and shear forces, respectively. Heavier (sheathed) panels significantly increased risks, although the magnitude of this effect differed with panel size and between tasks. Higher levels of risk were found in tasks originating from ground vs. knuckle height. Several practical recommendations based on the results are discussed. STATEMENT OF RELEVANCE: Panelised wall systems have the potential to increase productivity in residential construction, but may result in increased worker injury risks. Results from this study can be used to generate future panel design and construction processes that can proactively address WMSD risks.     

Ergonomic postural assessment using a new open-source human pose estimation technology (OpenPose)

Observational ergonomic postural assessment methods have been commonly used to evaluate the risks of musculoskeletal disorders. Researchers have proposed semi-automatic methods using Kinect, known for limitations with body occlusions and non-frontal tracking. Meanwhile, new human pose estimation methods have been actively developed, and a popular open-source technology is OpenPose. This study aims to propose the OpenPose-based system for computing joint angles and RULA/REBA scores and validate against the reference motion capture system, and compare its performance to the Kinect-based system. Recordings of 10 participants performing 12 experimental tasks under different conditions: with/without body occlusions and tracked from frontal/non-frontal views were analyzed. OpenPose showed good performance under all task conditions, whereas Kinect performed significantly worse than OpenPose especially at cases with body occlusions or non-frontal tracking. The findings suggested that OpenPose could be a promising technology to measure joint angles and conduct semi-automatic ergonomic postural assessments in the real workspace where the conditions are often non-ideal.     

Low back injury risks during construction with prefabricated (panelised) walls: effects of task and design factors

New technology designed to increase productivity in residential construction may exacerbate the risk of work-related musculoskeletal disorders (WMSDs) among residential construction workers. Of interest here are panelised (prefabricated) wall systems (or panels) and facilitating an ongoing effort to provide proactive control of ergonomic exposures and risks among workers using panels. This study, which included 24 participants, estimated WMSD risks using five methods during common panel erection tasks and the influences of panel mass (sheathed vs. unsheathed) and size (wall length). WMSD risks were fairly high overall; e.g. 34% and 77% of trials exceeded the ‘action limits’ for spinal compressive and shear forces, respectively. Heavier (sheathed) panels significantly increased risks, although the magnitude of this effect differed with panel size and between tasks. Higher levels of risk were found in tasks originating from ground vs. knuckle height. Several practical recommendations based on the results are discussed.

Statement of Relevance:Panelised wall systems have the potential to increase productivity in residential construction, but may result in increased worker injury risks. Results from this study can be used to generate future panel design and construction processes that can proactively address WMSD risks.     

Ergonomic assessment based on monocular RGB camera in elderly care by a new multi-person 3D pose estimation technique (ROMP)

Nursing staff members are at high risk of work-related musculoskeletal disorders (WMSDs), which not only threaten their health but also impact the quality of elderly care. Ergonomic posture risk assessment (EPRA) is usually employed to identify potential WMSD risks such as extreme posture and repetitive movements. A monocular RGB camera has been used for the EPRA in recent years due to its short time requirements and low cost. However, most work scenarios do not involve multi-person situations.Therefore, based on the latest 3D pose estimation algorithm—Monocular, One-stage Regression of Multiple 3D People (ROMP)—this study proposes a method that uses one monocular RGB camera to conduct the EPRA in multi-person and occluded scenarios. The accuracy of our method was calculated through 12 care tasks involving multi-person and occlusion, using the Noitom motion capture (MoCap) system.The results show that our method performed well, with an average accuracy of 83.8% and 90.7%, respectively, using two EPRA scoring tools, RULA and OWAS. The mean absolute error (MAE) of each joint angle was 9.4°. Thus, ROMP seems to be a potential method for conducting the EPRA in nursing workspaces with unsatisfactory conditions using a single monocular RGB camera.     

A multilayered ergonomic intervention program on reducing musculoskeletal disorders in an industrial complex: A dynamic participatory approach

Work-related musculoskeletal disorders (WMSDs) are closely identified with common complaints in different workplaces. This study aimed to implement an intervention program through which ergonomic measures were dynamically localized in industry. An interventional study, including three basic layers, namely, training workshops, participatory ergonomics (PE), and workstation redesign was fulfilled in an Iranian steel manufacturing complex from 2017 to 2020. A steering committee (SC) was formed following several meetings held for clarification of the project to the management team. The SC members then attended four organized workshops managed by an ergonomics specialist. Afterwards, the basics of ergonomics were transferred to action groups. After developing ergonomic assessment tools, the ergonomic problems were prioritized and numerous positive changes were made by the action groups. The findings of the tailored checklists revealed a load of WMSDs risk factors. All the three layers of the program were implemented as initiated. Ergonomics training workshops were then held and significant differences were observed between the participants' pre/posttest mean scores in all workshops (p < 0.001). Moreover, PE measures were exercised at all levels of the organization inducing enthusiastic motivation of the workforce to consider ergonomic requirements in the workplace. Consequently, the workers' innovative ideas and the managerial support yielded diverse workstation redesigns due to a growth in either the workers' ergonomics awareness or participatory culture grounding. A multilayered ergonomic intervention was implemented in this study. In conclusion, a multifaceted long-term follow-up intervention program could be applied to enhance workers’ health status and to raise system productivity.     

Kinematics differences between obese and non-obese workers during vertical handling tasks

Obesity is highly prevalent in the workforce but little is known about its effects on musculoskeletal disorders risk factors, such as the posture adopted during work activity. Vertical Handling Tasks (VHT), including manual lifting and lowering loads, are quite frequent in industrial settings and are considered to be a major cause of Work-Related Musculoskeletal Disorders (WMSD). Therefore, the main objective of this study is to compare and analyse the strategies and postures adopted during VHT between obese and non-obese subjects. A kinematics study with the VICON® system was conducted within a convenience sample of 8 non-obese (4 women and 4 men) and 8 obese (4 women and 4 men) volunteers participants. Different occupational conditions were tested over 8 trials of VHT. When developing VHT, the obese group presents kinematics significant differences (p < 0.05), compared with non-obese, namely: a decrease in the duration of the tasks, an increase in the horizontal distance between the load and the body worker, and an increase of the trunk sagittal flexion. This study demonstrates that obese individuals are exposed to a higher level of WMSD risk, during VHT performance.Relevance to industryThe findings are relevant to ergonomic workstations/job design for obese workers. This study defends that obesity can be a WMSD risk factor during VHT frequently found in industry, pointing to the need of companies to include this factor during ergonomic interventions on workstations and to adopt obesity prevention measures.     

Risk assessments of work-related musculoskeletal disorders among the TFT-LCD manufacturing operators

The thin film transistor liquid crystal display (TFT-LCD) industry is one of the major industries in Taiwan, yet few studies addressed its work-related musculoskeletal disorders (WMSDs). Thus, this study aims to evaluate the risk of WMSDs among the operators of a TFT-LCD manufacturing company in Taiwan by using the subjective questionnaire and ergonomic assessment tools. First, the NMQ survey was conducted among 393 operators, accounting for 94% of all operators in the TFT-LCD plant. The results showed that the prevalence of WMSDs was 31.8%. Among the various body parts, the highest prevalence of WMSDs was found in neck and shoulders (20.4%), while upper limbs were with the lowest prevalence (9.2%). Besides, the prevalence of WMSDs tends to be affected by both work factors and operator factors. Those who were more experienced, working in day shift and involved in the Array process tend to have a higher prevalence of WMSDs. Further, female and domestic operators reported a higher prevalence of WMSDs than male and foreign operators. Moreover, the jobs of 50 employees were analyzed using ergonomic assessment tools including OSHA MSDs, BRIEF, OWAS, 3D SSPP, and NIOSH lifting equation. The findings indicated that inadequate working height, restricted working space, awkward postures, overweight load, and high repetition were the major risk factors of WMSDs. Thus, countermeasures such as redesigning the workstations and material handling carts, proactive training of manual material handling, and providing safety clearance are recommended to enhance the occupational health and safety of the TFT-LCD operators.     

A generic algorithm for computing optimal ergonomic postures during working in an industrial environment

The present study tries to decrease the risk of work-related musculoskeletal disorders for industry workers by proposing a generic algorithm that recommends an optimal ergonomic posture for accomplishing tasks in an industrial environment. In the case of a dangerous ergonomic pose, the optimization algorithm starts by heuristically changing it to a more ergonomic one. Each recommended posture's feasibility is tested with an inverse kinematic method that can predict the worker's behavior for accomplishing a task. This iterative optimization procedure continues until the optimal ergonomic pose for the worker is achieved. The algorithm's validity is tested in thirteen cases, people with different gender (50 percent male, 50 percent female) aged between 20 and 35, and different height and body morphologies. According to studies, there is a connection between musculoskeletal disorders and the wrong posture for accomplishing tasks in industries. We suggest an optimization algorithm that can indicate the worker the optimal ergonomic pose by considering task constraints in real-time.     

A privacy-preserving and unobtrusive sitting posture recognition system via pressure array sensor and infrared array sensor for office workers

Sitting posture recognition is essential in preventing work-related musculoskeletal disorders (WMSDs). WMSDs are of huge concern for office workers whose working process is averagely 81.8% sedentary. Prevailing studies have utilized cameras, wearables, and pressure sensors to recognize sitting postures. The cameras and wearables can achieve accurate recognition results, while personal privacy concerns and inconvenience for long-term use impede their adoption. Meanwhile, the pressure sensors are privacy-preserving and convenient. However, they cannot accurately recognize the sitting posture with different states of the trunk, head, upper extremity, and lower extremity. Considering the pros and cons of those approaches, this study proposes a novel privacy-preserving and unobtrusive sitting posture recognition system, which combines a pressure array sensor with another privacy-preserving sensing technology, i.e., an infrared array (IRA) sensor. Moreover, a deep learning-based sitting posture recognition algorithm is developed, which adopts a feature-level fusion strategy and does not require a complex handcrafted feature extraction process. Based on the ergonomics studies, ten daily sitting postures with the states of different body parts are selected. This system achieved an overall 90.6% accuracy using the leave-subject-out validation approach based on the self-collected dataset from 21 subjects. It has a great potential for privacy-preserving and unobtrusive related applications for sitting posture management.     

Assessing exposure to risk factors for work-related musculoskeletal disorders using Quick Exposure Check (QEC) in taxi drivers

Work-related musculoskeletal disorders (WMSDs) are a common health problem throughout the world. This study aimed to examine the risk factors that are involved in the development of WMSDs in taxi drivers. In total 382 taxi drivers were observed using Quick Exposure Check (QEC) observational tool, which allows practitioners and workers to assess four key areas of the body. Results of the QEC scores were found to be very high for the shoulder/arm, wrist/hand and neck, whereas the scores for the back were found to be high for static use and moderate for moving. The results also showed that the occupational risk factors for WMSDs were associated with restricted postures, repetitive movements, vibration, work related stress. Essential ergonomic interventions are needed to eliminate risk of exposures to WMSDs in taxi drivers.Relevance to industryThe study results have relevance for ergonomists, health and safety practitioners as well as the drivers themselves, and helpful for estimating the main physical risk factors for WMDSs before choosing a method prior to an ergonomic intervention in industry.     

Prevalence of work-related musculoskeletal symptoms among grocery workers

Work-related musculoskeletal disorders (WMSDs) affect all sectors of the working population, and grocery workers have especially high rates. Although the incidence of WMSDs among any worker population can be estimated from workers' compensation claims, musculoskeletal symptom surveys can be used as a proxy estimate of WMSDs. The purposes of this cross-sectional study were to describe the prevalence of work-related musculoskeletal symptoms in grocery store employees from many different departments, and to determine the association between exposure to physical risk factors and presence of symptoms. Study participants (N = 254) were grocery store workers from five different stores in a medium sized grocery chain. Participants completed a self-administered survey consisting of demographic information and job history; the modified Nordic Questionnaire (MNQ); and physical component (PCS) and mental component (MCS) summary measures of the SF-36v2^®. Rodgers Muscle Fatigue Analysis (Rodgers) was used to assess exposure to physical risk factors in the most difficult tasks in certain store departments. Prevalence of musculoskeletal symptoms was estimated for each body region and for various subgroups, and multivariable logistic regression analysis was used to identify independent predictors of presence of musculoskeletal symptoms. Approximately 78% of grocery store workers reported work-related musculoskeletal symptoms in at least one body region, with most workers complaining of low back and feet symptoms. The high prevalence of foot symptoms has not been previously reported for this population. Approximately 11% of employees missed work because of symptoms and 25% sought medical care for symptoms. There were no differences among Rodgers rating groups for proportions reporting symptoms. SF-36v2^® scores were inconsequential predictors for musculoskeletal symptoms. Gender and age were both significant predictors of symptoms, and age predicted healthcare utilization. These findings are relevant to the grocery industry in order to target WMSD preventive interventions to specific body regions for high-risk activities within a grocery store position.