Bernardino Ramazzini's early observations of the link between musculoskeletal disorders and ergonomic factors

Bernardino Ramazzini (1633-1714) systematically studied the relationship between work and diseases. He realized that it was not possible to ascribe all workers' diseases to chemicals or physical agents and foresaw that other factors were involved. He observed that common diseases could originate following the maintenance either of prolonged stationary postures or of unnatural postures (e.g. bakers, workers who stand, sedentary worker, scribes, weavers) or following activities requiring heavy muscular performance (e.g. porters and woodworkers). Furthermore, Ramazzini recognized the need to undertake measures to prevent disorders from repetitive motions and manual lifting and anticipated the now accepted advice of moderation and recommendations of reduction of work duration for a number of hard jobs requiring a standing position or severe muscular effort. From his early writings therefore it is evident that Ramazzini realized the importance of assessing the ergonomic factors associated with the occurrence of work-related musculoskeletal disorders.     

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.     

Safety climate,hardiness, and musculoskeletal complaints: A mediated moderation model

This study explores the mechanisms linking the psychosocial characteristics of the workplace with employees' work-related musculoskeletal complaints. Poor safety climate perceptions represent a stressor that may elicit frustration, and subsequently, increase employees' reports of musculoskeletal discomforts. Results from an employee sample supported that when employees' perceived safety was considered a priority, they experienced less frustration and reported fewer work-related upper body musculoskeletal symptoms. Psychological hardiness, a personality trait that is indicative of individuals' resilience and success in managing stressful circumstances, moderated these relationships. Interestingly, employees with high hardiness were more affected by poor safety climate.     

Development of an intervention to prevent work-related musculoskeletal disorders among hospital nurses based on the participatory approach

The participatory approach has been widely used to improve the work environment. The purpose of this study was to develop an intervention to prevent work-related musculoskeletal disorders in hospital nurses using the participatory approach. Based on the Participatory Action Oriented Training (PAOT) approach, the multidisciplinary team conducted the trainer workshop to develop a comprehensive intervention protocol, which yielded several practical and low-cost solutions to reduce the risk factors for musculoskeletal disorders. Structured tools that were focused on the hospital environment were developed. The developed action checklist consisted of 43 items that were focused on five areas of nursing tasks (i.e., patient care and treatment; safe handling of drugs, medical devices, and equipment; workstation design; physical environment; and welfare facilities and administration). The final intervention protocol consisted of a series of structured participant workshop, follow-up visits, and presentation of achievements.     

Digital vibration threshold testing and ergonomic stressors in automobile manufacturing workers: a cross-sectional assessment

Upper extremity musculoskeletal disorders (UEMSDs) comprise a large proportion of work-related illnesses in the USA. Physical risk factors including manual force and segmental vibration have been associated with UEMSDs. Reduced sensitivity to vibration in the fingertips (a function of nerve integrity) has been found in those exposed to segmental vibration, to hand force, and in office workers. The objective of this study was to determine whether an association exists between digital vibration thresholds (VTs) and exposure to ergonomic stressors in automobile manufacturing. Interviews and physical examinations were conducted in a cross-sectional survey of workers (n=1174). In multivariable robust regression modelling, associations with workers' estimates of ergonomic stressors stratified on tool use were determined. VTs were separately associated with hand force, vibration as felt through the floor (whole body vibration), and with an index of multiple exposures in both tool users and non-tool users. Additional associations with contact stress and awkward upper extremity postures were found in tool users. Segmental vibration was not associated with VTs. Further epidemiologic and laboratory studies are needed to confirm the associations found. The association with self-reported whole body vibration exposure suggests a possible sympathetic nervous system effect, which remains to be explored.     

Distress and worry as mediators in the relationship between psychosocial risks and upper body musculoskeletal complaints in highly automated manufacturing

As a result of changes in manufacturing including an upward trend in automation and the advent of the fourth industrial revolution, the requirement for supervisory monitoring and consequently, cognitive demand has increased in automated manufacturing. The incidence of musculoskeletal disorders has also increased in the manufacturing sector. A model was developed based on survey data to test if distress and worry mediate the relationship between psychosocial factors (job control, cognitive demand, social isolation and skill discretion), stress states and symptoms of upper body musculoskeletal disorders in highly automated manufacturing companies (n = 235). These constructs facilitated the development of a statistically significant model (RMSEA 0.057, TLI 0.924, CFI 0.935). Cognitive demand was shown to be related to higher distress in employees, and distress to a higher incidence of self-reported shoulder and lower back symptoms. The mediation model incorporating stress states (distress, worry) as mediators is a novel approach in linking psychosocial risks to musculoskeletal disorders.

Practitioners’ Summary

With little requirement for physical work in many modern automated manufacturing workplaces, there is often minimal management focus on Work-Related Musculoskeletal Disorders (WRMSDs) as important occupational health problems. Our model provides evidence that psychosocial factors are important risk factors in symptoms of WRMSD and should be managed.     

Investigation of oil palm harvesting tools design and technique on work-related musculoskeletal disorders of the upper body

The oil palm industry is one of the important sectors in Malaysia. The growth and development of this industry shows that Malaysia is the world second-largest oil palm producers. However, in the fresh fruit bunch (FFB) harvesting process, the harvesters are exposed to many types of work-related musculoskeletal disorders (WMSDs). The FFB harvesters tend to develop WMSDs especially the shoulders and trunk. Hence, it is important to identify the exposure levels, awkward postures and the reaction forces of muscle activity based on the posture and movement of the harvesters when using pole, chisel and loading spike during the harvesting process. The objective of this study was to investigate the effect of the design of oil palm FFB harvesting tools on WMSDs of the upper body. Rapid Upper Limb Analysis (RULA) was used to investigate and assess the exposure level on the harvester body during the harvesting process. The assessment showed that the shoulders and trunk have high exposure level and undergo awkward posture. Human Musculoskeletal Model Analysis (HMMA) was used to identify the reaction force exerted on the muscle during the FFB harvesting process. In this study, 4 muscles were analysed including Triceps, Biceps, Erector Spinae and Psoas Major. The highest reaction force of 16.36 N was found on the left triceps when handling a loading spike. In conclusion, it is important to address the risks by reviewing all possible aspects that contribute to the WMSDs and interventions on the tool design, task and working shifts may be required.     

Standardized low-load repetitive work: evidence of different motor control strategies between experienced workers and a reference group

The purpose of this laboratory study was to evaluate the possible differences in motor strategies to a new standardized low-load repetitive work task in between healthy experienced workers and a reference group. Work task event duration, i.e. working rhythm, cutting forces, surface electromyographic (EMG) activity from four shoulder muscles, postural activity, and arm and trunk movements in 3D were recorded during low-load repetitive work simulation. The experienced group showed lower EMG activity and frequency contents (P<0.05), more abducted position of the upper arm and forward flexion of the trunk prior to work simulation (P<0.05), and increased arm and trunk range of motion (P<0.05) compared with the reference group. The results highlight that experienced butchers have a different motor strategy compared with a reference group, i.e. more variable form of coordination pattern. Furthermore, the initial implementation of a possible protective motor strategy by experienced workers might be a very important prognostic factor.     

Ergonomic assessment of musculoskeletal risk among a sample of Portuguese emergency medical technicians

The prevalence of musculoskeletal disorders in healthcare professionals is high, patient handling tasks being one of the main causes. This article focused on the analysis of the risk of musculoskeletal disorders in patient handling tasks, performed by emergency medical technicians. The study included 20 technicians from the National Institute of Medical Emergency and a total of 292 analysed postures. REBA results indicated that, of the 292 postures, 47% presented a medium risk and 29% high risk. The task “transport of the chair on the stairs - bottom position” obtained the most critical REBA score and the task “placement of the stair chair into the ambulance - top position” involved higher effort, according to the technicians’ perception. With this study, it was possible to diagnose the risk level of musculoskeletal disorders in tasks of manual handling performed by these professionals, allowing to identify specific actions that can compromise their health and safety. Hereafter, based on risk factors identification, it is relevant to the sector to develop solutions for these first responders, focusing on design features, based on an ergonomics participatory methodology.     

Effects of personal,psychosocial and occupational factors on low back pain severity in workers

Low back pain (LBP) remains the most common work-related musculoskeletal disorder (WMSD). While most of the LBP research has focused on occupational risk factors, other underlying causal mechanisms may exist since not all workers performing the same task develop an injury. Previous research has identified three primary risk factor categories for LBP (occupational, personal and psychosocial factors); however, few studies have investigated the impact of cross categorical risk factor interactions on LBP. The objective of this study was to investigate the effects of occupational, personal and psychosocial factors, and their interactions, on LBP severity in a population of workers currently suffering from LBP. Sixty LBP patients recruited for the study through local physicians and local announcements, completed questionnaires relating to identified occupational, personal and psychosocial risk factors, and completed an Oswestry Disability Index (ODI). Multiple regression models for predicting LBP severity were developed for each risk factor category and for a combined risk factor model (which included factors from all three risk factor categories) that included two-way interactions. Results showed that the final model consisted of both main effects and interaction terms between risk factor categories and had an adjusted R² value of 0.85, a significant improvement over models developed for the individual categories. These findings illustrate the need to consider all three broad categories of risk factors simultaneously in predicting injury status and in developing effective potential intervention efforts.     

The relationship between work productivity and acute responses at different levels of production standard times

Work productivity is typically associated with production standard times. Harder production standards generally result in higher work productivity. However, the tasks become more repetitive in harder production standard time and workers may be exposed to higher rates of acute responses which will lead to higher risks of contracting work-related musculoskeletal disorders (WMSDs). Hence, this paper seeks to investigate the relationship between work productivity and acute responses at different levels of production standard times. Twenty industrial workers performed repetitive tasks at three different levels of production standard time (PS), corresponding to “normal (PSN)”, “hard (PSH)” and “very hard (PSVH)”. The work productivity and muscle activity were recorded along these experimental tasks. The work productivity target was not attainable for hard and very hard production standard times. This can be attributed to the manifestations of acute responses (muscle activity, muscle fatigue, and perceived muscle fatigue), which increases as the production standard time becomes harder. There is a strong correlation between muscle activity, perceived muscle fatigue and work productivity at different levels of production standard time. The relationship among these variables is found to be significantly linear (R = 0.784, p < 0.01). The findings of this study are indeed beneficial to assess the existing work productivity of workers and serves as a reference for future work productivity planning in order to minimize the risk of contracting WMSDs.     

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.     

Full shift arm inclinometry among dairy parlor workers: a feasibility study in a challenging work environment

Over the last 20 years, the US dairy industry has experienced a significant transformation from small farm operations to an industrialization of the milking process. This transformation has resulted in improvements in process efficiency and product quality. Milking tasks in large-herd parlors are highly-repetitive involving awkward postures and high muscle loads of the upper extremity. Field-based direct measures of physical exposures have been limited in challenging work settings such as dairies. This study evaluated full-shift exposures of posture and motion of the upper extremity among large-herd parlor milkers using wireless inclinometry. Results suggest large-herd parlor workers may be exposed to high exposure levels (posture, movement velocity, repetition, and inadequate rest) associated with the development of shoulder pathology. Compared to other high-risk occupations involving shoulder-intensive work, parlor workers may have higher exposure levels. These findings warrant the need for continued field-based research with larger sample sizes to facilitate the development of cost-effective intervention strategies.     

Physical risks of work-related musculoskeletal complaints among quarry workers in East of Iran

Quarry workers are at high risk of developing musculoskeletal complaints. The aim of this study was to evaluate the working postures and prevalence of musculoskeletal problems among quarry workers. In this cross-sectional study 78 male quarry workers were assessed using the method of Rapid Entire Body Assessment (REBA), and musculoskeletal complaints data were obtained by the Standardized Nordic Musculoskeletal questionnaire (NMQs). Results of the prevalence of musculoskeletal problems in body parts of stonemasonry workers was higher found than in the stonecutting workers. The highest prevalence rate of musculoskeletal problems in both stonemasonry and stonecutting workers was 65.7% and 54.8% respectively related to waist. The stonemasons with 62% had high level of risk and stone cutting workers with 47.6% had moderate risk level. Significant correlation was found among age, work experience, BMI, and prevalence of musculoskeletal problems. There was also a significant relationship between the wrist and lower back pain with the risk level of REBA score. The study results showed that musculoskeletal problems of workers had high prevalence and accordingly most of the work conditions and postures needed to be improved, so prioritizing the necessity of corrective actions and intervention are to be gained.     

The effect of vibration on psychophysically derived work frequencies for a riveting task

A laboratory experiment was conducted to determine maximum acceptable task frequencies (MAF) for males performing a simulated riveting task at different wrist postures and applied force levels using an operational rivet gun. Twelve healthy males from a university population served as subjects. Results indicated that MAF decreased significantly with a deviation in wrist posture and an increase in applied force. These results were supported by various physiological variables and ratings of perceived exertion. It was also determined that decrements in MAF due to vibration were 36% while decrements due to wrist posture were 19%. This would indicate that vibration, as a risk factor in the development of work-related musculoskeletal disorders, is of more concern than wrist posture. Implication of the findings are discussed in the body of the paper.Relevance to industry

Ergonomic intervention may decrease the development of work-related musculoskeletal disorders thus reducing workers compensation costs and lost productivity of the worker.     

The relationships between work intensity,workaholism, burnout,and self‐reported musculoskeletal complaints

Technological advances within the work environment have dynamically changed the tools with which work is done and the methods applied for performing it, with a large amount of modern work being fast‐paced and sedentary in nature, that is, being done seated in front of a computer screen. This study investigated the relationship between work intensity, workaholism, burnout, and musculoskeletal complaints (MSCs). The results of this study could assist organizations in gaining a clearer understanding of how each of these constructs influences the other, promoting a healthier, and ultimately more productive workforce. A cross‐sectional research design was adopted and implemented by means of a survey amongst office employees within a large engineering services organization (n = 398). Structural equation modeling methods were applied to analyze the data. The results revealed that work intensity was positively related to workaholism and that workaholism was, in turn, also positively related to employees’ burnout and MSCs. Finally, burnout was also shown to be significantly related to MSCs. Awareness of these phenomena and the promotion of effort recovery is important to obviate the effects on employee health and well‐being in the long term.     

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.     

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.     

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.