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.     

Psychophysical Demands and Perceived Workload—An Ergonomics Standpoint for Lean Production in Assembly Cells

The adoption of a lean production model means a systematic implementation of various management methods and practices. Such a model presents the human element as a key factor in continuous improvement efforts, influencing workers’ job content and the quality of work. However, there are few evidences regarding research on quantitative assessment of the work demand, either psychological or physical, in a lean production environment. Therefore, this study aims to analyze from an ergonomics perspective the psychophysical demand and workers’ perceived workload within assembly cells undergoing a lean production implementation. The proposed method integrates complementary concepts of widely known techniques, enabling the consolidation of several assessment criteria into one particular index for both psychological and physical demands. Such a diagnostic method is illustrated in a case study from the automotive parts manufacturing sector, whose application is performed in three critical assembly cells selected by senior management. Our findings show systemic gaps between work demand and employees’ profile, indicating improvement opportunities in order to provide a better work environment.     

Nonlinear dynamical systems for theory and research in ergonomics

Abstract

Nonlinear dynamical systems (NDS) theory offers new constructs, methods and explanations for phenomena that have in turn produced new paradigms of thinking within several disciplines of the behavioural sciences. This article explores the recent developments of NDS as a paradigm in ergonomics. The exposition includes its basic axioms, the primary constructs from elementary dynamics and so-called complexity theory, an overview of its methods, and growing areas of application within ergonomics. The applications considered here include: psychophysics, iconic displays, control theory, cognitive workload and fatigue, occupational accidents, resilience of systems, team coordination and synchronisation in systems. Although these applications make use of different subsets of NDS constructs, several of them share the general principles of the complex adaptive system.

Practitioner Summary: Nonlinear dynamical systems theory reframes problems in ergonomics that involve complex systems as they change over time. The leading applications to date include psychophysics, control theory, cognitive workload and fatigue, biomechanics, occupational accidents, resilience of systems, team coordination and synchronisation of system components.     

Effectiveness of a participatory ergonomics intervention in improving communication and psychosocial exposures

A participatory ergonomics programme was implemented in an automotive parts manufacturing factory in which an ergonomics change team was formed, composed of members from management, the organized labour union and the research team. It was hypothesized that the participatory nature of this change process would result in enhanced worker perceptions of workplace communication dynamics, decision latitude and influence, which in conjunction with anticipated mechanical exposure reductions would lead to reduced worker pain severity. Utilizing a sister plant in the corporation as a referent group, a quasi-experimental design was employed with a longitudinal, repeat questionnaire approach to document pre-post intervention changes. Nine participatory activities (psychosocial interventions) were implemented as part of the process. Communication dynamics regarding ergonomics were significantly enhanced at the intervention plant compared to the referent plant. However, there were no significantly different changes in worker perceptions of decision latitude or influence between the two plants, nor did pain severity change. Possible explanations for these results include limited intervention intensity, context and co-intervention differences between the two plants, high plant turnover reducing the statistical power of the study and lack of sensitivity and specificity in the psychosocial measures used. Further research should include the development of psychosocial tools more specific to participatory ergonomic interventions and the assessment of the extent of change in psychosocial factors that might be associated with improvements in pain.     

Occupational ergonomics research and applied contextual design implementation for an industrial shop-floor workstation

The aim of this original research article is to identify the occurrence of work-related ergonomics risk factors, in order to implement context specific human centered design interventions in the injection molding shop-floor workstations of plastic furniture manufacturing factories within the framework of industrially developing countries. Questionnaire study, postural assessment tools, computer aided design, digital human modeling and simulation, and basic work study techniques were used. Plastic processing industry is highly fragmented, consisting of small, medium scale enterprises with tremendous growth potential. Occupational design ergonomics research in the injection molding plastic furniture manufacturing shop-floor workstations is very scarce in industrially developing countries. Shop-floor workers are affected by prevalent awkward working postures and consequent body part discomforts. Useful and easily implementable accessories/fixtures with convenient design features were conceptualized. Virtual ergonomics evaluation of the workstation with proposed accessories/fixtures showed significant reduction of awkward working postures. Physical prototypes of the proposed fixtures were constructed and real human trials were performed in the factories. Time study indicated reduction in operator cycle time when compared with time taken before design modifications. Research methodology, results and design solutions described from an ergonomics perspective would definitely serve as a helpful guide for existing as well as upcoming factories in the injection molded plastic furniture manufacturing industry of industrially developing countries and further similar research endeavors.     

Effectiveness of a participatory ergonomics intervention in improving communication and psychosocial exposures

A participatory ergonomics programme was implemented in an automotive parts manufacturing factory in which an ergonomics change team was formed, composed of members from management, the organized labour union and the research team. It was hypothesized that the participatory nature of this change process would result in enhanced worker perceptions of workplace communication dynamics, decision latitude and influence, which in conjunction with anticipated mechanical exposure reductions would lead to reduced worker pain severity. Utilizing a sister plant in the corporation as a referent group, a quasi-experimental design was employed with a longitudinal, repeat questionnaire approach to document pre-post intervention changes. Nine participatory activities (psychosocial interventions) were implemented as part of the process. Communication dynamics regarding ergonomics were significantly enhanced at the intervention plant compared to the referent plant. However, there were no significantly different changes in worker perceptions of decision latitude or influence between the two plants, nor did pain severity change. Possible explanations for these results include limited intervention intensity, context and co-intervention differences between the two plants, high plant turnover reducing the statistical power of the study and lack of sensitivity and specificity in the psychosocial measures used. Further research should include the development of psychosocial tools more specific to participatory ergonomic interventions and the assessment of the extent of change in psychosocial factors that might be associated with improvements in pain.     

The relationship between physical workload and quality within line-based assembly

Reducing costs and improvement of product quality are considered important to ensure productivity within a company. Quality deviations during production processes and ergonomics have previously shown to be associated. This study explored the relationship between physical workload and real (found during production processes) and potential (need of extra time and assistance to complete tasks) quality deviations in a line-based assembly plant. The physical workload on and the work rotation between 52 workstations were assessed. As the outcome, real and potential quality deviations were studied during 10 weeks. Results show that workstations with higher physical workload had significantly more real deviations compared to lower workload stations. Static work posture had significantly more potential deviations. Rotation between high and low workload was related to fewer quality deviations compared to rotation between only high workload stations. In conclusion, physical ergonomics seems to be related to real and potential quality deviation within line-based assembly.

Practitioner Summary: To ensure good productivity in manufacturing industries, it is important to reduce costs and improve product quality. This study shows that high physical workload is associated with quality deviations and need of extra time and assistance to complete tasks within line-based assembly, which can be financially expensive for a company.     

Mental workload and cognitive task automaticity: an evaluation of subjective and time estimation metrics

Abstract

The evaluation of mental workload is becoming increasingly important in system design and analysis. The present study examined the structure and assessment of mental workload in performing decision and monitoring tasks by focusing on two mental workload measurements: subjective assessment and time estimation. The task required the assignment of a series of incoming customers to the shortest of three parallel service lines displayed on a computer monitor. The subject was either in charge of the customer assignment (manual mode) or was monitoring an automated system performing the same task (automatic mode). In both cases, the subjects were required to detect the non-optimal assignments that they or the computer had made. Time pressure was manipulated by the experimenter to create fast and slow conditions. The results revealed a multi-dimensional structure of mental workload and a multi-step process of subjective workload assessment. The results also indicated that subjective workload was more influenced by the subject's participatory mode than by the factor of task speed. The time estimation intervals produced while performing the decision and monitoring tasks had significantly greater length and larger variability than those produced while either performing no other tasks or performing a well practised customer assignment task. This result seemed to indicate that time estimation was sensitive to the presence of perceptual/cognitive demands, but not to response related activities to which behavioural automaticity has developed.     

Automotive HMI design and participatory user involvement: review and perspectives

Abstract

Automotive human–machine interface (HMI) design is facing new challenges due to the technological advances of the last decades. The design process has to be adapted in order to address human factors and road safety challenges. It is now widely accepted that user involvement in the HMI design process is valuable. However, the current form of user involvement in industry remains at the stages of concept assessment and usability tests. Moreover, the literature in other fields (e.g. information systems) promotes a broader user involvement with participatory design (i.e. the user is fully involved in the development process). This article reviews the established benefits of participatory design and reveals perspectives for automotive HMI quality improvement in a cognitive ergonomic framework.

Practitioner Summary: Automotive HMI quality determines, in part, drivers’ ability to perform primary driving tasks while using in-vehicle devices. User involvement in the design process is a key point to contribute to HMI quality. This article reports the potential benefits of a broad involvement from drivers to meet automotive HMI design challenges.     

Micro- and macroergonomic changes in mental workload and medication safety following the implementation of new health IT

Health information technology (IT) is a promising way to achieve safer medication management in the delivery of healthcare. However, human factors/ergonomics dictates that in order to make the complex, cognitive work of healthcare delivery safer, health IT must properly support human cognition. This means, for example, that new health IT must reduce, not increase, workload during safety-critical tasks. The present study was the first to quantitatively assess the short- and long-term impact of bar coded medication administration (BCMA) IT on nurses' mental workload as well as on perceived medication safety. One-hundred seventy registered nurses across 3 dissimilar clinical units at an academic, freestanding pediatric hospital in the Midwest US participated in surveys administered before, 3 months after, and 12 months after the hospital implemented BCMA. Nurses rated their external mental workload (interruptions, divided attention, being rushed) and internal mental workload (concentration, mental effort) during medication administration tasks as well as the likelihood of each of three medication safety events: medication administration errors, medication errors on the clinical unit, and clinical unit-level adverse drug events. Clinical unit differences were assessed. Findings generally confirmed the hypothesis that external but not internal mental workload was associated with the perceived likelihood of a medication safety event. Comparisons of mental workload from pre- to post-BCMA revealed statistically significant changes in the critical care unit only. Medication safety appeared to improve over the long term in the hematology/oncology unit only. In the critical care and medical/surgical units, medication safety exhibited short-term improvements that were eliminated over time. Changes in mental workload and medication safety, two classically microergonomic constructs, were deeply embedded in macroergonomic phenomena. These included the fit between the BCMA system and the nature of nursing work, the process of BCMA implementation, and BCMA interactions with concurrent changes occurring in the hospital. Findings raise questions about achieving sustainable performance improvement with health IT as well as the balance between micro- and macroergonomic approaches to studying technology change.Relevance to industryDesigners must consider how technology changes cognitive work, including mental workload. Hospitals and other implementers of technology must ensure that new technology fits its users, their tasks, and the context of use, which may entail tailoring implementation, for example, to specific clinical units. Evaluators must look over time to assess both changes in cognitive work and implementation issues. Healthcare practitioners must also recognize that new technology means a complex transformation to an already complex sociotechnical system, which calls for a macroergonomic approach to design and analysis.     

Fitting methods to paradigms: are ergonomics methods fit for systems thinking?

Abstract

The issues being tackled within ergonomics problem spaces are shifting. Although existing paradigms appear relevant for modern day systems, it is worth questioning whether our methods are. This paper asks whether the complexities of systems thinking, a currently ubiquitous ergonomics paradigm, are outpacing the capabilities of our methodological toolkit. This is achieved through examining the contemporary ergonomics problem space and the extent to which ergonomics methods can meet the challenges posed. Specifically, five key areas within the ergonomics paradigm of systems thinking are focused on: normal performance as a cause of accidents, accident prediction, system migration, systems concepts and ergonomics in design. The methods available for pursuing each line of inquiry are discussed, along with their ability to respond to key requirements. In doing so, a series of new methodological requirements and capabilities are identified. It is argued that further methodological development is required to provide researchers and practitioners with appropriate tools to explore both contemporary and future problems.

Practitioner Summary: Ergonomics methods are the cornerstone of our discipline. This paper examines whether our current methodological toolkit is fit for purpose given the changing nature of ergonomics problems. The findings provide key research and practice requirements for methodological development.     

A manufacturing-oriented model for evaluating the satisfaction of workers – Evidence from Turkey

Job satisfaction, in terms of worker's satisfaction, is one of the intensively studied areas in human resource and management. However, there is little information available on how ergonomics and the manufacturing environment affect job satisfaction. This study analyzes the extent of the relationship between job satisfaction and work and workplace related conditions. A conceptual model is proposed to evaluate job satisfaction that considers 34 elements in four categories: manufacturing systems, facility design, safety and ergonomics, and human resources and management. A survey of 169 blue-collar workers working in the automotive industry was conducted to investigate the applicability of the model. A comprehensive exploratory factor analysis was used to determine inter-related elements, their underlying factors and their effects on job satisfaction. The analysis revealed 6 factors with 18 related elements. From a multi linear regression analysis, we develop a job satisfaction model built on factors of human resource policies, safety, ergonomics, air quality, thermal comfort and disturbing equipment. The results reveal that ergonomics plays the most important role in workers' satisfaction for the respondent Turkish automotive workers. In contrast, human resource policies seem not play a critical role in job satisfaction because of higher standards in automotive industry compared to other industries in Turkey.     

Integrating ergonomics and engineering in the technical design process

Leyland DAF and the University of Nottingham collaborated in establishing an ergonomics team to support the truck design and development process in the company. The project was planned within the framework of a Teaching Company Scheme funded jointly by Leyland DAF and the UK government. This framework provided a training environment in which the team, which was formed of young professional ergonomists and engineers, could quickly acquire the specialist skills needed for work in the automotive industry in addition to gaining practical experience in applying ergonomics, and the programme was structured to promote the integration of ergonomics and engineering considerations within the technical design process. The experience gained in this project has shown the benefits of such an approach to implementing ergonomics in product design, and provided an insight into the ways in which ergonomists and designers can communicate more effectively in a manufacturing organization.     

Design and implementation of a participatory ergonomics program for machine sewing tasks

A participatory ergonomics program was designed and implemented to control and reduce workers' compensation costs within an automobile products manufacturing company. Pareto analysis identified a substantial number of musculoskeletal disorders (MSD) associated with manual, machine sewing of canvas automobile accessory products. This case study will discuss the elements of the participatory ergonomics program, describe its implementation, highlight intervention measures, and present program results. Specifically, during the period of 1993 to 1996, the participatory ergonomics program played a significant part in reducing the number of MSD claims by approximately 85%, and contributed to an overall reduction in workers' compensation incurred loss costs by approximately 42%.     

A comparative analysis of participatory ergonomics programs in U.S. and Japan manufacturing plants

The use of a participative approach to ergonomics is growing in countries throughout the world. This paper compares and contrasts Participatory Ergonomics programs in two U.S. and two Japanese manufacturing plants. All four programs focused on the redesign of repetitive manufacturing jobs to reduce physical stress on workers. In all four cases, this traditional ergonomics concern was addressed in a non-traditional way-involving broad participation of many manufacturing functions who worked together as an ergonomics team and direct input from operators whose jobs were redesigned.

The participatory ergonomics programs were successful in making significant numbers of job changes in both countries. A comparison of the ergonomics programs across countries revealed some significant differences in structure and process. An overarching difference was in how participation was managed. In the Japan cases, participation was a carefully controlled process by which upper management and staff specialists worked through first-line supervisors to get input from workers meeting in quality (or safety) circles. In the U.S., multi-functional and multi-level task forces (including union and worker representatives) were formed and operators were invited to meetings to give input. The U.S. plants gave the task force a great deal of autonomy and virtually all decisions were group decisions. The differences suggest that effective participatory ergonomics programs can take many forms. The best program for any particular plants in differing countries depends on their own unique history, structure, and culture.     

A defeasible reasoning framework for human mental workload representation and assessment

Human mental workload (MWL) has gained importance in the last few decades as an important design concept. It is a multifaceted complex construct mainly applied in cognitive sciences and has been defined in many different ways. Although measuring MWL has potential advantages in interaction and interface design, its formalisation as an operational and computational construct has not sufficiently been addressed. This research contributes to the body of knowledge by providing an extensible framework built upon defeasible reasoning, and implemented with argumentation theory (AT), in which MWL can be better defined, measured, analysed, explained and applied in different human–computer interactive contexts. User studies have demonstrated how a particular instance of this framework outperformed state-of-the-art subjective MWL assessment techniques in terms of sensitivity, diagnosticity and validity. This in turn encourages further application of defeasible AT for enhancing the representation of MWL and improving the quality of its assessment.     

Automatic assembly path planning for wiring harness installations

The automotive industry of today is becoming more focused on electrified and hybrid solutions, where both conventional combustion engines and battery supplied electrical engines need to fit in an already densely packed vehicle. Many quality problems are related do flexible parts. In particular, the assembly of electric cables and wiring harnesses is difficult due to its concealed routing, multiple branching points, weights and the flexibility in the material. To avoid late detection of assembly problems, the assembly aspect must be considered early during conceptual design and production preparation with respect to both feasibility and ergonomics. Development of automatic path planning methods in virtual manufacturing tools supporting deformable parts is therefore highly motivated.     

Cultural influences on the measurement of subjective mental workload

Cognitive ergonomics is well entrenched in North American and most European work environments, where systems and products are designed with the capabilities and limitations of the user in mind. A prominent technique for analysing task demands is subjective mental workload measurement. Subjective ratings of mental workload have been shown—in North American and European populations—to be reliable and sensitive to changes in mental workload. However, there is reason to think that cultural differences may affect subjective ratings. This study compared the performance and subjective mental workload ratings of Indonesian (n = 87) and Dutch (n = 88) students in the context of a hybrid memory/visual search task. Performance was comparable for the two groups, but the sensitivity of the subjective workload measures was better in the Dutch than in the Indonesian group. The results are interpreted in light of social axioms and cultural values.

Statement of Relevance: Now more than ever ergonomists must think beyond national borders in improving work processes. Globalisation requires that cultural differences be taken into account in developing and applying ergonomic techniques. This paper presents empirical work showing that cultural differences seriously impact the sensitivity of mental workload measures.     

Workload-based multi-task scheduling in cloud manufacturing

Cloud manufacturing is an emerging service-oriented business model that integrates distributed manufacturing resources, transforms them into manufacturing services, and manages the services centrally. Cloud manufacturing allows multiple users to request services at the same time by submitting their requirement tasks to a cloud manufacturing platform. The centralized management and operation of manufacturing services enable cloud manufacturing to deal with multiple manufacturing tasks in parallel. An important issue with cloud manufacturing is therefore how to optimally schedule multiple manufacturing tasks to achieve better performance of a cloud manufacturing system. Task workload provides an important basis for task scheduling in cloud manufacturing. Based on this idea, we present a cloud manufacturing multi-task scheduling model that incorporates task workload modelling and a number of other essential ingredients regarding services such as service efficiency coefficient and service quantity. Then we investigate the effects of different workload-based task scheduling methods on system performance such as total completion time and service utilization. Scenarios with or without time constraints are separately investigated in detail. Results from simulation experiments indicate that scheduling larger workload tasks with a higher priority can shorten the makespan and increase service utilization without decreasing task fulfilment quality when there is no time constraint. When time constraint is involved, the above strategy enables more tasks to be successfully fulfilled within the time constraint, and task fulfilment quality also does not deteriorate.     

Putting the brain to work: neuroergonomics past, present, and future

OBJECTIVE: The authors describe research and applications in prominent areas of neuroergonomics. BACKGROUND: Because human factors/ergonomics examines behavior and mind at work, it should include the study of brain mechanisms underlying human performance. METHODS: Neuroergonomic studies are reviewed in four areas: workload and vigilance, adaptive automation, neuroengineering, and molecular genetics and individual differences. RESULTS: Neuroimaging studies have helped identify the components of mental workload, workload assessment in complex tasks, and resource depletion in vigilance. Furthermore, real-time neurocognitive assessment of workload can trigger adaptive automation. Neural measures can also drive brain-computer interfaces to provide disabled users new communication channels. Finally, variants of particular genes can be associated with individual differences in specific cognitive functions. CONCLUSIONS: Neuroergonomics shows that considering what makes work possible - the human brain - can enrich understanding of the use of technology by humans and can inform technological design. APPLICATION: Applications of neuroergonomics include the assessment of operator workload and vigilance, implementation of real-time adaptive automation, neuroengineering for people with disabilities, and design of selection and training methods.