Related Musculoskeletal Disorders Research Articles

Epidemiological study to investigate potential interaction between physical and psychosocial factors at work that may increase the risk of symptoms of musculoskeletal disorder of the neck and upper limb

Objectives: To investigate potential interactions between physical and psychosocial risk factors in the workplace that may be associated with symptoms of musculoskeletal disorder of the neck and upper limb. Methods:...

Integration of Ergonomics Into Hand Tool Design: Principle and Presentation of an Example

The development of ergonomic tools responds to health protection needs on the part of workers, especially the work related musculoskeletal disorders of the upper limbs and to the development of ergonomic tools to take into account the needs of the factories. Only an ergonomic design process can enable tool manufacturers to meet these requirements. Three factors are involved: integration of ergonomics into the design process, definition of the different ergonomic stages involved, and finally knowledge of the different factors involved in hand tool design. This document examines these 3 elements in more detail and presents briefly a project of research whose main purpose is to integrate ergonomic criteria into a design process.

Physical workload during manual and mechanical deboning of poultry

The physical workload after the introduction of new technology, i.e. mechanical versus manual deboning of poultry was studied with respect to force requirements, work postures and repetitive movements of the hand. Thirteen healthy women were studied during manual and mechanical deboning using electromyography (EMG), force recordings, observer based force ratings and electrogoniometers. The muscular activity was significantly higher in Extensor Carpi Ulnaris (ECU), Flexor Carpi Ulnaris (FCU), and Flexor Digitorum Superficialis (FDS) during cutting—the most strenuous task of manual deboning—than during mechanical deboning. Estimated cutting forces were 6.3 and 20.7 N (median and peak levels) . Extreme wrist postures were more frequent during cutting, but peak acceleration and repetition—calculated from spectral analysis of the goniometer signal—were higher during mechanical deboning. In general the introduction of new technology, i.e. mechanical deboning had only marginal effects on the risk factors associated with work related musculoskeletal disorders during poultry processing. Mechanical deboning moderately reduced peak forces, but the muscular activity remained high, and in addition higher levels of acceleration and repetition rates were introduced. Observer based estimations of the hand forces correlated in these work tasks well with the mean peak EMG level of the relevant muscles. Relevance to industry New technology must carefully be evaluated with regard to physical exposure regarding force, repetitiveness and work postures, before it is introduced in the work place.

Reducing Back and Shoulder Injuries in the Nursing Home Industry

Work related musculoskeletal disorders (WMSDs) such as low back pain, tendinitis, hand arm vibration syndrome and carpal tunnel syndrome, account for a major component of the cost of work-related illness and injury in the United States. The National Occupational Research Agenda (NORA) musculoskeletal team identified intervention studies of engineering and work organizational improvements as a high priority in reducing the burden of WMSDs. In Washington State, direct workers compensation costs are more than $410 million per year. Nursing homes have high claims incidence of back and shoulder WMSDs, related primarily to resident handling activities. A cooperative industrywide “zerolift” initiative has resulted in significant reductions in back and shoulder WMSD claims and costs in the Washington State nursing home industry. Rates have decreased 19% in those nursing homes receiving workers compensation premium discounts for purchasing equipment compared to 3% reduction for those nursing homes without premium discounts. Payback on investment in “zerolift” programs appears to take 6–12 months.

Ergonomics and Prevention of Disability Due to Musculoskeletal Disorders: A State-of-the-Science Symposium

This symposium is concerned with rehabilitation, ergonomics and preventing work disability. Specifically it is concerned with determining the state of the science and identifying research opportunities that could result in major reductions in work disability. Disability has be defined as (Brandt and Pope 1997): Disability is defined as a limitation in performing certain roles and tasks that society expects of an individual It is the expression of the gap between a person's capabilities and the demands of the environment - the interaction of person's limitations with social and physical environmental factors. Available data show that there are many persons in our society who are disabled in that they are unable to achieve expectations established by employers, e.g., production rates, quantities and quality, without endangering themselves or others in the workplace or community. This expectation typically extends to forty hours per week, but could be more or less hours. Limitations in performance may result from conditions of birth, illness or injury. They also may be a primary or secondary effect of work. This is the case with Work Related Musculoskeletal Disorders; WMSDs. WMSDs are a leading cause of work disability and compensation in many contemporary work settings. Although this program focuses on prevention of disability due to WMSDs, it is broadly concerned with the prevention of all disability. The models and methods discussed have common elements that are applicable to many if not all persons and situations. For example, the above definition defines disability as a “gap” between job demands and worker capacities. This definition applies to a person with paraplegia as well as a person with carpal tunnel syndrome. In both instances, methods are needed for assessing and comparing worker capacities and job demands. The program includes presentations by leading investigators who will draw on their own work and work of others to describe the state of the art and develop recommendations for future research.

Results of a survey on the awareness and severity assessment of upper-limb work-related musculoskeletal disorders among female bank tellers in Korea

The purpose of this study was to investigate the relationship between self-reported musculoskeletal symptoms and related factors among VDT operators working in banks. The subjects were 950 female bank tellers. This study was the first nation-wide survey on WMSDs carried out to specify the prevalence of WMSDs and to identify demographic and task-related factors associated with work related musculoskeletal disorders (WMSDs) symptoms. The resulting prevalence rates were much higher than similar studies conducted in other countries. In the ‘more than severe’ category for the Likert scale, subjects reported 51.4% for the shoulder, 38.3% for the lower back, 38.0% for the neck, 31.2% for the upper back, 21.7% for the wrist, and 13.6% for the fingers. The demographic characteristics affecting the WMSD symptoms were marital status, number of children and daily time spent on housework. Task-related factors affecting the symptoms were VDT working experience, daily working time, daily VDT use, VDT use time without rest, daily workload, and the amount of rest breaks. Multiple logistics regression showed that daily working time, daily VDT use time, and VDT working experience were significant variables accounting for the symptoms. Relevance to industry Work-related musculoskeletal disorders (WMSDs) are an important health concern for industry. This study provides information on the prevalence and severity of WMSDs in Korea with specific reference to comparable studies conducted in the USA and other countries. This study will contribute to the knowledge of the problems and thus will help practitioners in the workplace of various countries who are faced with WMSD problems.

Increase of physical activity level after successful renal transplantation: a 5 year follow-up study.

Physical activity (PA) level of end-stage renal disease (ESRD) patients after renal transplantation (TP) is a largely unexplored field, although it is an important component of quality of life. Using the Baecke self-administered and the Five-City Project 7-day PA recall questionnaires, PA level was estimated in 32 consecutive ESRD patients (12 males, 20 females; mean age 45.9+/-13.1 years; mean dialysis duration 23.5+/-21.8 months) admitted for renal TP and to whom no exercise programme of any kind was proposed. PA were recorded 1, 3, 6, 12 and 60 months after TP. Immediate pre-TP PA level of renal transplant candidates was between 18 and 35% less than that of age-matched healthy subjects (P < 0.05), depending on gender and questionnaire. After an immediate decrease in PA level 1 month post-TP, mean PA level increased and reached a plateau 1 year after TP. This gain in PA capacity reached 30%, as compared with pre-TP values (P = 0.06 to P < 0.01). During the fifth year after TP, the mean level of PA was unchanged. A more qualitative analysis, allowed by the sub-score comparisons, showed that although the occupational status of the patients remained the same, they participated significantly more in moderate and even high intensity PA (leisure, sports, household chores) after TP. Most renal graft recipients are spontaneously more active after TP, an observation consistent with a better quality of life. Therefore, they should be advised precisely about how to resume more strenuous activities such as sports in order to avoid cardiac or musculoskeletal disorders in relation to their weakened pre-TP condition.

Trabalho de grupo com portadores de LER/DORT: relato de experiência

Neste artigo, apresenta-se e discute-se as contribuições da Psicologia ao estudo das Lesões por Esforços Repetitivos ou Distúrbios Osteomusculares Relacionados ao Trabalho (LER/DORT). Privilegia-se a análise do trabalho com grupos de portadores de tal patologia, prestado por uma equipe multidisciplinar do Hospital de Clínicas de Porto Alegre, em parceria com a Faculdade de Medicina e o Instituto de Psicologia da Universidade Federal do Rio Grande do Sul. Parte-se do pressuposto de que o estudo da relação entre saúde e trabalho constitui-se como importante espaço de atuação do psicólogo e que são necessárias produções textuais, a partir de relatos de experiências, que apresentem, sistematizem e fundamentem propostas de intervenção. As atividades com grupos, complementando os procedimentos terapêuticos convencionais, têm possibilitado que os portadores de LER/DORT possam diminuir sua culpabilização e reforçar sua independência e autonomia, minimizando, assim, o sofrimento psicológico associado à dor crônica e aos limites impostos pela doença.

Occupational health and safety in physiotherapy: Guidelines for practice

Most physiotherapists (91%) experience work related musculoskeletal disorders (WMSDs) at some time, and one in six makes a career change as a consequence. Many of these disorders are attributed to manual handling of patients. This paper proposes guidelines to reduce the risk of WMSDs based on Australian legislative requirements, the results of a survey of Australian physiotherapists and the literature surrounding injury prevention. These guidelines address the areas of environmental and job design, and the personal physical capabilities of physiotherapists, within the context of law. The paper concludes by calling for further research to explore and develop this area of injury prevention in the physiotherapy profession.

Occupational Musculoskeletal Disorders.

Occupational Musculoskeletal Disorders. Ed. 2. Nortin M. Hadler. Philadelphia, Lippincott Williams and Wilkins, 1999. $75.00, 433 pp. Hadler reminds us that clinical science, like the law, is subject to the political pressures of the day in the formulation of the hypotheses to be tested and in the frame of reference for interpreting the results. Well known in legal and medical circles, Hadler has served on several national commissions on musculoskeletal disorders in relation to the workplace. In this book, he does not attack but instead thoughtfully and critically analyzes popular concepts and beliefs in medicine and a Workers' Compensation system that has gone awry because it is based on …

Office Ergonomic Interventions: Strategies and Practices

Organizations today are seeking ways to use the work environment as a means of improving worker effectiveness, prevent work related musculoskeletal disorders and to enhance worker health and well-being. This paper presents three case studies where companies have designed, implemented and evaluated office ergonomics interventions. Incorporating a work systems design approach can provide an effective framework for successful office ergonomics interventions.

Ergonomics for Assembly for Automotive Design Engineers

Since the early 1990s a concept known as Design for Manufacturability (DFM) has developed. In the past much of the ergonomics involvement in DFM has considered the workstations and methods of human assembly operators. The increase in health and safety regulations and the number of employee compensation claims against companies for work related musculoskeletal disorders is providing the impetus for the consideration of Ergonomics for Assembly (EA) by design engineers. This project was undertaken within the context of an automotive manufacturing company. A programme for EA training for product design engineers was developed and a system proposed to support its incorporation in future design work.

A Study of the Use of a Wrist Splint to Prevent WMSDs at a Sprout Grower

Awkward postures and repetitive forceful motions have been implicated as risk factors for the development of work related musculoskeletal disorders (WMSDs). The use of wrist splints in the work environment has been adapted by some employers in an effort to control at least one of these risk factors. The hypothesis follows that if workers wear wrist splints they can avoid awkward wrist postures, which may reduce their risk for the development of WMSDs. The affect of the wrist splint on the amount of force exerted by the workers is unknown. This study was undertaken at a sprout grower to analyze the relative force exerted by workers with and without a splinted dominant wrist during two hand intensive jobs. It was found that the ability to exert peak grip force was significantly impaired with the use of the wrist splint. In addition, extrinsic flexor electromyography (EMG) and anterior deltoid EMG were relatively higher while subjects worked with splinted wrists as compared to working without a wrist splint. This preliminary data suggests that a wrist splint may limit awkward wrist postures at the expense of increasing the force required to perform hand intensive tasks. The opinions expressed in this paper are those of the authors and do not necessarily represent the opinions of the Occupational Safety and Health Administration.

Risk Assessment Based on Scientific Knowledge of Muscular Strain in Different Cleaning Tasks

Work related musculoskeletal disorders are frequently reported for persons employed in occupational cleaning. For effective prevention it is necessary to identify work conditions that represent a biomechanical and physiological overload for the different structures and segments of the body. The literature shows that cleaning work is associated with high muscle load levels. Repetitive muscular work of the upper extremities and high levels of dynamic and static force are apparent in cleaning tasks. Surface EMG recordings from the trapezius, deltoid and infraspinatus muscles during wet cleaning of surfaces above floor level and floor cleaning with various mopping systems show high loads for the shoulder muscles. In light of scientific knowledge, interchanging cleaning tasks does not seem to introduce sufficient variation in the load profile of the shoulder muscles. The overall strategy for improving work conditions in cleaning work is to introduce variation either by job enlargement or by frequent rest periods.

From Training in Ergonomic Diagnosis to Finding Solutions: Assessment of Ergo Groups that Used Participatory Ergonomics

The goal of this article is to present the training given to ergonomic groups to teach them how to transform work situations in a company producing primary aluminium. It presents the transition from the ergonomic diagnosis (9) conducted by the groups (7) to the solutions they considered during a brainstorming session, the weighing of the solutions and, finally to the ideas retained for industrial transformation projects. The results show that the most numerous ideas and those that were most often retained concerned equipment-tools category. Of the ideas expressed, 50.5% and 40.5% were retained for transformation projects in the “equipment-tools” and “layout” categories, respectively. In this study, the ability of the ergonomics-trained groups to find relevant solutions for the prevention of work related musculoskeletal disorders (MSDs) seems undeniable to us.

Adverse Work Stress Reactions — A Review of the Potential Influence on Work Related Musculoskeletal Disorders (WMSDS)

Available data show that work stress and work-related musculoskeletal disorders (WMSDs) are the leading occupational health burdens in Member States of the European Union. Cross-sectional data do no provide a clear indication of the impact of work stress upon WMSDs. Studies have used different indicators for stress and this makes comparison between them more difficult. Similar workplace risk factors, including physical and psychosocial, seem to be associated with work stress and WMSDs. Stress has been implicated in the pathology of WMSDs but many hypotheses require further investigation. There is some epidemiological evidence to support work stress reactions as a predictor of WMSDs and a weighted reciprocal relationship may also exist between these two health problems. However, more longitudinal studies are required to clarify this issue.

Ergonomic Analysis of Movement Retraining of Computer Users: A Pilot Study

Two groups of movement retrained computer users with prior computer-related upper extremity musculoskeletal disorders underwent qualitative orthogonal video motion analysis. Ergonomic analysis of subjects' computer use habits suggests that movement retraining may decrease risk factors for work related musculoskeletal disorders and therefore warrants further study.

Work Analysis and Work Changes through Onsite Ergonomics Training for Small Groups

This paper deals with two case studies of onsite training on Ergonomics for small groups of non-OSH professionals from two state-owned companies from São Paulo State, Brazil. Both (1997 and 1998) training programs aimed at enabling small group of employees to function as an intern Ergonomics Committee. Their main and first task was to identify, evaluate, control and prevent risk factors and WRMD - Work Related Musculoskeletal Disorders, with or without the support of external consultant/ergonomists. This paper identifies and discusses main difficulties arising from such training programs and implementing work transformations. Some of the main difficulties may arise from the scheduling of short-term courses (36 to 48h of classes) for non-OSH professionals that are not used to group work, learning on matter as WRMD. Difficulties also originate from the nature of the task: (try) to enable mostly non-ergonomists/non OSH professionals to develop group-guided actions on matter that sometimes require immediate action, specialized knowledge and long-term experience in the field of Ergonomics and diagnosis of a company's demand. Last but not the least, the paper also points out key factors to work transformations: the placing of training programs within a company's OSH policy and context; group formation criteria for such training programs; course schedule, content, planning and evaluation; the need for full discussion of the short-term and the long-term results of the training program as well as of the follow-up of any work transformations.

Ergonomics and occupational medicine: future challenges.

Ergonomics has come a long way since the birth of the subject some 50 years ago. It now has an established research base and an appropriate portfolio of methodologies. A brief overview of the subject's development will be presented, with a particular focus on the contribution of ergonomics to our understanding of work related musculoskeletal disorders. Future challenges are also considered in this area, with particular emphasis on the need for a multidisciplinary approach to many industrial problems where the ergonomist, occupational physician and other professionals are needed to tackle existing and future work problems. Additionally, the importance of participatory ergonomics is considered, with respect to understanding and advancing solutions in this area. The issues of the ageing workforce and the challenges that must be met are also outlined. This area again emphasizes the need for a multidisciplinary team approach that is proactive and designed to maximize the health and wellbeing of workers at all ages, whilst also ensuring a full and productive life.

Sensitivity of trapezius electromyography to differences between work tasks — influence of gap definition and normalisation methods

Surface electromyography (EMG) has been used extensively to estimate muscular load in studies of work related musculoskeletal disorders, especially for the trapezius muscle. The occurrences of periods of EMG silence (gaps), the time below a predetermined threshold level (muscular rest) and various percentiles of the amplitude distribution (APDF) are commonly used summary measures. However, the effects of the criteria used to calculate these measures (e.g., gap duration, threshold level, normalisation method) on the sensitivity of these measures to accurately differentiate work loads is not well known. Bilateral trapezius EMG was recorded, for a full workday, for 58 subjects following both maximal (MVE) and submaximal (RVE) reference contractions. Gap frequency, muscular rest, and percentiles were derived for eight fundamental work tasks. The calculations were performed using different gap duration criteria, threshold levels and normalisation methods. A gap duration of less than 1/2 s, and threshold level ≈0.3% MVE for gap frequency, and ≈0.5% MVE for muscular rest, were the criteria that optimised sensitivity to task differences. Minimal sensitivity to tasks and a high sensitivity to individuals was obtained using gap frequency with a threshold level of ≈1% MVE. Normalisation to RVE, rather than MVE, improved sensitivity to differences between tasks, and reduced undesirable variability. Muscular rest was more sensitive to task differences than APDF percentiles.