The costs of work-related musculoskeletal disorders in automotive manufacturing

Usability, User Acceptance, and Health Outcomes of Arm-Support Exoskeleton Use in Automotive Assembly: An 18-month Field Study

OBJECTIVE

Examine arm-support exoskeleton (ASE) user experience over time, identify factors contributing to ASE intention-to-use, and explore whether ASE use may influence the number of medical visits.

METHODS

An 18-month, longitudinal study with ASE (n = 65) and control groups (n = 133) completed at nine automotive manufacturing facilities.

RESULTS

Responses to six usability questions were rather consistent over time. ASE use perceived effective in reducing physical demands on the shoulders, neck, and back. Perceived job performance, and overall fit and comfort, appeared to be key determinants for ASE intention-to-use. Based on medical visits among both groups, ASE use may decrease the likelihood of such visits.

CONCLUSIONS

These field results support the potential of ASEs as a beneficial ergonomic intervention, but also highlight needs for further research on ASE designs, factors driving intention-to-use, and health outcomes.

Ergonomic Assessment of Material Handling in CV Joint Assembly

Work-Related Musculoskeletal Disorders (WRMSD) is one of the most common problems that affect productivity in industrial processes. This chapter presents the ergonomic evaluation of the main tasks in a Constant Velocity (CV) Joint assembly process. Tasks selected and evaluated using ergonomic methods were the transport of manufacturing parts on carts, parts supply at the workstation, materials handling within the workstation, and loading of the finished product on pallets. The ergonomic evaluation was performed by applying both Rapid Entire Body Assessment (REBA) method, and Rodgers' Biomechanical analysis. The analysis showed the existence of very high and high risk levels. Body regions most affected were elbow, shoulder, trunk, hip, legs, arm, and wrist. Ultimately, this research highlights the urgent need to perform corrective actions and further assessment for the CV Joint assembly process tasks studied.

The long-term burden of work-related carpal tunnel syndrome relative to upper-extremity fractures and dermatitis in Washington State

BACKGROUND

Carpal tunnel syndrome (CTS) is among the most burdensome of all musculoskeletal disorders as measured by workers' compensation claims costs and lost earnings. But the burden of CTS extends beyond direct claim costs.

METHODS

A survey covering health, social, economic and work-related outcomes was administered to 1,255 injured workers whose Washington State Fund workers' compensation claims had closed 6 years previously. Logistic and linear regression methods were used to model the outcomes of CTS claimants across four separate outcome domains.

RESULTS

Workers diagnosed with CTS suffer substantial deficits across all four outcome domains as compared to the two comparison groups of claimants. Former CTS claimants were almost twice as likely not to be working as compared to the fractures cohort.

CONCLUSIONS

A comprehensive measurement of the burden of CTS shows losses extend beyond direct claims costs to include continuing pain, loss of function, adverse financial impacts and household disruption which extend long after claim closure. Am. J. Ind. Med. 58:1255-1269, 2015. © 2015 Wiley Periodicals, Inc.

Relationships between job organisational factors, biomechanical and psychosocial exposures

The relationships between work organisational, biomechanical and psychosocial factors were studied using cross-sectional data from a pooled dataset of 1834 participants. The work organisational factors included: job rotation, overtime work, having second jobs and work pace. Task and job level biomechanical variables were obtained through sub-task data collected in the field or analysed in the laboratory. Psychosocial variables were collected based on responses to 10 questions. The results showed that job rotations had significant effects on all biomechanical and most psychosocial measures. Those with job rotations generally had higher job biomechanical stressors, and lower job satisfaction. Overtime work was associated with higher job biomechanical stressors, and possibly self-reported physical exhaustion. Those having second jobs reported getting along with co-workers well. Work pace had significant influences on all biomechanical stressors, but its impact on job biomechanical stressors and psychosocial effects are complicated.

PRACTITIONER SUMMARY

The findings are based on a large number of subjects collected by three research teams in diverse US workplaces. Job rotation practices used in many workplaces may not be effective in reducing job biomechanical stressors for work-related musculoskeletal disorders. Overtime work is also associated with higher biomechanical stressors.

Shoulder muscle fatigue during repetitive tasks as measured by electromyography and near-infrared spectroscopy

OBJECTIVE

The objective of this study was to quantify shoulder muscle fatigue during repetitive exertions similar to motions found in automobile assembly tasks.

BACKGROUND

Shoulder musculoskeletal disorders (MSDs) are a common and costly problem in automotive manufacturing.

METHOD

Ten subjects participated in the study. There were three independent variables: shoulder angle, frequency, and force. There were two types of dependent measures: percentage change in near-infrared spectroscopy (NIRS) measures and change in electromyography (EMG) median frequency. The anterior deltoid and trapezius muscles were measured for both NIRS and EMG. Also, EMG was collected on the middle deltoid and biceps muscles.

RESULTS

The results showed that oxygenated hemoglobin decreased significantly due to the main effects (shoulder angle, frequency, and force). The percentage change in oxygenated hemoglobin had a significant interaction attributable to force and repetition for the anterior deltoid muscle, indicating that as repetition increased, the magnitude of the differences between the forces increased. The interaction of repetition and shoulder angle was also significant for the percentage change in oxygenated hemoglobin. The median frequency decreased significantly for the main effects; however, no interactions were statistically significant.

CONCLUSIONS

There was significant shoulder muscle fatigue as a function of shoulder angle, task frequency, and force level. Furthermore, percentage change in oxygenated hemoglobin had two statistically significant interactions, enhancing our understanding of these risk factors.

APPLICATION

Ergonomists should examine interactions of force and repetition as well as shoulder angle and repetition when evaluating the risk of shoulder MSDs.

Musculoskeletal disorder risk during automotive assembly: current vs. seated

Musculoskeletal disorder risk was assessed during automotive assembly processes. The risk associated with current assembly processes was compared to using a cantilever chair intervention. Spine loads and normalized shoulder muscle activity were evaluated during assembly in eight regions of the vehicle. Eight interior cabin regions of the vehicle were classified by reach distance, height from vehicle floor and front to back. The cantilever chair intervention tool was most effective in the far reach regions regardless of the height. In the front far reach regions both spine loads and normalized shoulder muscle activity levels were reduced. In the middle and close reach regions spine loads were reduced, however, shoulder muscle activity was not, thus an additional intervention would be necessary to reduce shoulder risk. In the back far reach region, spine loads were not significantly different between the current and cantilever chair conditions. Thus, the effectiveness of the cantilever chair was dependent on the region of the vehicle.

A conceptual framework for integrating workplace health promotion and occupational ergonomics programs

Musculoskeletal, cardiovascular, and mental health are all associated with the physical and psychosocial conditions of work, as well as with individual health behaviors. An integrated approach to workplace health-promotion programs should include attention to the work environment, especially in light of recent findings that work organization influences so-called lifestyle or health behaviors. Macroergonomics provides a framework to improve both physical and organizational features of work and, in the process, to empower individual workers. The Center for the Promotion of Health in the New England Workplace (CPH-NEW) is a research-to-practice effort examining the effectiveness of worksite programs that combine occupational safety and health--especially ergonomics--with health promotion, emphasizing the contribution of work organization to both. Two intervention studies are underway in three different sectors: health care, corrections, and manufacturing. Each study features participatory structures to facilitate employee input into health goal-setting, program design and development, and evaluation, with the goal of enhanced effectiveness and longer-term sustainability.

Occupational health among Latino workers: a needs assessment and recommended interventions

Evidence suggests that Latino workers, along with other minority and low-income workers, face a higher risk for occupational disease than do other workers. Targeted surveillance and primary prevention interventions have been lacking or inadequate. The authors estimate the number of occupational disease deaths and new cases in Latino workers in the United States. Then, using data from New York City, they find that Latino workers are disproportionately employed in more hazardous occupations and underrepresented in less hazardous jobs. They suggest a comprehensive approach to address workplace disease in Latino workers, which involves primary prevention interventions, clinical services, educational approaches, research and surveillance, unionization and organization of workers, and legislation and regulation.

Estimating the global burden of low back pain attributable to combined occupational exposures

BACKGROUND

There is little information about the global burden of non-traumatic low back pain (LBP) attributable to the effects of physical and psychosocial occupational stressors.

METHODS

Based on a review of the epidemiological evidence, occupation-specific relative risks were used to compute attributable proportions by age, gender, and geographical sub-region for the economically active population aged 15 and older. The reference group was professional/administrative workers; other risk categories were Low, clerical and sales; Moderate, operators (production workers) and service; and High, farmers.

RESULTS

Worldwide, 37% of LBP was attributed to occupation, with twofold variation across regions. The attributable proportion was higher for men than women, because of higher participation in the labor force and in occupations with heavy lifting or whole-body vibration. Work-related LBP was estimated to cause 818,000 disability-adjusted life years lost annually.

CONCLUSIONS

Occupational exposures to ergonomic stressors represent a substantial source of preventable back pain. Specific research on children is needed to quantify the global burden of disease due to child labor.

Work-related musculoskeletal disorders: the epidemiologic evidence and the debate

The debate about work-relatedness of musculoskeletal disorders (MSDs) reflects both confusion about epidemiologic principles and gaps in the scientific literature. The physical ergonomic features of work frequently cited as risk factors for MSDs include rapid work pace and repetitive motion, forceful exertions, non-neutral body postures, and vibration. However, some still dispute the importance of these factors, especially relative to non-occupational causes. This paper addresses the controversy with reference to a major report recently commissioned by the US Congress from the National Research Council (NRC) and Institute of Medicine (IOM) (2001). The available epidemiologic evidence is substantial, but will benefit from more longitudinal data to better evaluate gaps in knowledge concerning latency of effect, natural history, prognosis, and potential for selection bias in the form of the healthy worker effect. While objective measures may be especially useful in establishing a more secure diagnosis, subjective measures better capture patient impact. Examination techniques still do not exist that can serve as a "gold standard" for many of the symptoms that are commonly reported in workplace studies. Finally, exposure assessment has too often been limited to crude indicators, such as job title. Worker self-report, investigator observation, and direct measurement each add to understanding but the lack of standardized exposure metrics limits ability to compare findings among studies. Despite these challenges, the epidemiologic literature on work-related MSDs-in combination with extensive laboratory evidence of pathomechanisms related to work stressors-is convincing to most. The NRC/IOM report concluded, and other reviewers internationally have concurred, that the etiologic importance of occupational ergonomic stressors for the occurrence of MSDs of the low back and upper extremities has been demonstrated.

Chronic pain in the workplace

Chronic pain, especially chronic back pain, is costly to workers, their families, employers, and society. Successful return to productive work life for the worker with chronic pain requires multi-disciplinary efforts, including those of the nurse case manager, occupational health nurse, and nursing specialist in pain management. Sensitivity to the dynamics of multiple stakeholders in the RTW process is essential because of their diverse perspectives. Successful RTW can be facilitated by a combination of approaches, including case management, worker capacity evaluation, ergonomic job analysis, team design of job modifications, appropriate medical treatment, and self management by the worker.