Effectiveness of ergonomic training to reduce physical demands and musculoskeletal symptoms - An overview of systematic reviews

Work-related musculoskeletal disorders are associated with awkward postures, excessive force, manual material handling and repetitive movements. This risk factors can be minimized through interventions such as ergonomic training. The literature covers several studies involving the use of this type of intervention, but there is no consensus about the effectiveness of ergonomic training. The aim of this study was to identify the available evidence about the effectiveness of ergonomic training to reduce physical work demand and musculoskeletal symptoms through an overview of systematic reviews. The searches were carried out in Pubmed/Medline, Web of Science, CINAHL, Embase and Cochrane Library. The START (State of the Art through Systematic Review, v.1.06.2) platform aided the selection and evaluation of studies. The studies were evaluated for methodological quality through the AMSTAR (Assessing the Methodological Quality of Systematic Reviews) criteria and the implications for practice. This overview identified a large number of studies with a low to moderate level of evidence, indicating the ineffectiveness of ergonomic training alone or associated with another type of intervention in reducing physical demand and musculoskeletal symptoms in workers. The findings may have occurred due to four main factors: superficial identification of the ergonomic risk factors; lack of scientific evidence about the appropriate configurations of the types of ergonomic training; ambiguous results in the application of ergonomic training; and the difficulty in the effectiveness of the intervention. The study identified an inconsistency in the level of evidence of ergonomic training to reduce physical demand and musculoskeletal symptoms among workers.     

A systematic review of comparative studies on ergonomic assessment techniques

This review provides a systematic overview of the comparison of ergonomic assessment techniques’ output in variety of industrial sectors.The relevant publications have been classified into broad categories such as comparison of applied industry sector, trend analysis, ergonomic assessment techniques been compared, comparative studies between two ergonomic assessment techniques, frequently compared techniques, levels of Action categories used. The summary of extracted data from included papers is provided.Authors have compared the results based on observational techniques which are easy to understand and apply. Available publications related to such comparison is limited. Authors have compared and analysed the correlation between the outputs of techniques but only few researchers pointed out the exact reason of variation in outputs applied in the same task. Hence, establishing applicability of each technique required. To identify the causes of variation, the sensitivity study of exposure factor-Task-posture assessment techniques is highly required. There are few techniques which are not yet compared for checking agreement or correlation, serving as a research gap.Authors have studied and published literature review specific to one technique of ergonomic assessment. Few authors have compared the outputs from various ergonomic assessment techniques in particular sector and investigated the correlation between them. No study has been carried out till date to review available literature on comparative study of comparisons made. In this paper, two research gaps have also been identified.     

Ergonomic Criteria Necessary to Epidemiological Studies in Industrial Medicine and Public Health

Abstract

While protective measures in industrialized countries mention ergonomic factors as possible means to improve health, safely and well-being at the work place, more and more ergonomic variables are introduced in recent epidemiological studies concerning the relationship between work hazards and health effects. After a short review of this literature, the author attempts to list relevant ergonomic criteria for further researches in industrial medicine and public health.

Critères Ergonomiques Nécessaires aux Études Épidémiologiques en Médecine du Travail et en Santé Publique

Notwendige Ergonomische Kriterien für Epidemiologische Studien in der Arbeitsmedizin und im Öffentlichen Gesundheitswesen     

Ergonomic interventions for commercial crab fishermen

Work tasks in the commercial fishing industry require strength, endurance and coordination and these tasks expose fishermen to many of the recognized risk factors for the development of work-related musculoskeletal disorders. The focus of the current study was the design, development and testing of two simple ergonomic interventions to reduce exposure to these risk factors in small-scale commercial crab fishermen. In a laboratory study of these interventions, EMG and motion analysis systems were used to quantify changes in muscle force and body postures. The results of laboratory evaluation of the intervention designed to reduce the low back stress associated with hoisting the crab pots onboard showed significant reductions in muscle force requirements (erector spinae activity reduced by 25%) and peak sagittal trunk angle (reduced by 34%), while the results of the intervention designed to reduce shoulder stress during the process of shaking the crabs from the pots showed significant reductions in peak deltoid activity (reduced by 24%). A field test of these interventions provided a more subjective “usability” evaluation of the interventions. These responses were cautiously positive, providing insights into when these interventions would be most appropriate and under what conditions they would be more of a hindrance than a help.

Relevance to industry

Engineering controls are recognized as the most effective methods of reducing exposure to risk factors for musculoskeletal injury. Engineering controls were developed for small-scale commercial crab fishermen and these interventions were tested in the laboratory and in the field.     

Effectiveness of participatory ergonomic interventions on health outcomes: a systematic review

The objective of this study was to conduct a systematic review of the literature on the effectiveness of participatory ergonomic (PE) interventions for improving workers' health. The search strategy targeted six electronic databases and identified 442 potential articles. Each article was examined by pairs of reviewers for relevance (assessed a participative ergonomic workplace intervention, with at least one health outcome, published in English in peer reviewed literature). Twenty-three articles met relevance criteria and were then appraised for methodological strength. Using a best evidence synthesis approach, 12 studies that were rated as 'medium' or higher provided partial to moderate evidence that PE interventions have a positive impact on: musculoskeletal symptoms, reducing injuries and workers' compensation claims, and a reduction in lost days from work or sickness absence. However, the magnitude of the effect requires more precise definition.     

Job stress management and ergonomic intervention for work-related upper extremity symptoms

In practice the secondary prevention of work-related upper extremity (WRUE) symptoms generally targets biomechanical risk factors. Psychosocial risk factors have also been shown to play an important role in the development of WRUE symptom severity and future disability. The addition of a stress management component to biomechanically focused interventions may result in greater improvements in WRUE symptoms and functional limitations than intervening in the biomechanical risk factors alone. Seventy office workers with WRUE symptoms were randomly assigned to an ergonomics intervention group (assessment and modification of work station and stretching exercises) or a combined ergonomic and job stress intervention group (ergonomic intervention plus two 1-h workshops on the identification and management of workplace stress). Baseline, 3- and 12-month follow-up measures of observed ergonomic risks and self-reported ergonomic risks, job stress, pain, symptoms, functional limitation, and general physical and mental health were obtained from all participants. While both groups experienced significant decreases in pain, symptoms, and functional limitation from baseline to three months with improvements continuing to 12 months post baseline, no significant differences between groups were observed for any outcome measures. Findings indicate that the additional two-session job stress management component did not significantly enhance the short- or long-term improvements brought about by the ergonomic intervention alone.     

The effects of occupational interventions on reduction of musculoskeletal symptoms in the nursing profession

The objective of the review was to gain more insight into the effects of occupational interventions for primary prevention of musculoskeletal symptoms in healthcare workers. The Cochrane Collaboration methodological guidelines for systematic reviews functioned as a starting point. Thirteen studies meeting the inclusion criteria were analysed for methodological quality and effects. Eight outcome effect areas were established and defined as areas in which an effect had been determined in at least two studies. A method based on levels of scientific evidence was then used to synthesize the information available. Strong scientific evidence for the beneficial effect of occupational interventions was found for the outcome effect areas physical discomfort, technical performance of transfers and frequency of manual lifting. Insufficient evidence was found for the effect areas absenteeism due to musculoskeletal problems, musculoskeletal symptoms, fatigue, perceived physical load and knowledge of risk factors at work and ergonomic principles. Training and education combined with an ergonomic intervention were found to be effective.     

The effects of occupational interventions on reduction of musculoskeletal symptoms in the nursing profession

The objective of the review was to gain more insight into the effects of occupational interventions for primary prevention of musculoskeletal symptoms in healthcare workers. The Cochrane Collaboration methodological guidelines for systematic reviews functioned as a starting point. Thirteen studies meeting the inclusion criteria were analysed for methodological quality and effects. Eight outcome effect areas were established and defined as areas in which an effect had been determined in at least two studies. A method based on levels of scientific evidence was then used to synthesize the information available. Strong scientific evidence for the beneficial effect of occupational interventions was found for the outcome effect areas physical discomfort, technical performance of transfers and frequency of manual lifting. Insufficient evidence was found for the effect areas absenteeism due to musculoskeletal problems, musculoskeletal symptoms, fatigue, perceived physical load and knowledge of risk factors at work and ergonomic principles. Training and education combined with an ergonomic intervention were found to be effective.     

Participatory ergonomics in design processes: the role of boundary objects

The aim of this paper is to introduce the concept of boundary objects in order to better understand the role of objects in participatory ergonomics (PE) design processes. The research question is: What characterizes boundary objects in PE processes? Based on two case studies, we identify eight characteristics of boundary objects and their use, which make them particularly useful in PE design processes. These characteristics go beyond the object itself and extend into the context of their use. We argue that the selection of boundary objects in PE processes is of great importance, since different objects enable workers’ participation and collaborative design in different ways. The framework developed may serve to provide criteria to guide practitioners and intervention researchers in the selection of objects to facilitate a PE process. The paper concludes with a list of recommendations for ergonomic practitioners that are based on the framework.     

Process and implementation of participatory ergonomic interventions: a systematic review

Participatory ergonomic (PE) interventions may vary in implementation. A systematic review was done to determine the evidence regarding context, barriers and facilitators to the implementation of participatory ergonomic interventions in workplaces. In total, 17 electronic databases were searched. Data on PE process and implementation were extracted from documents meeting content and quality criteria and synthesised. The search yielded 2151 references. Of these, 190 documents were relevant and 52 met content and quality criteria. Different ergonomic teams were described in the documents as were the type, duration and content of ergonomic training. PE interventions tended to focus on physical and work process changes and report positive impacts. Resources, programme support, ergonomic training, organisational training and communication were the most often noted facilitators or barriers. Successful PE interventions require the right people to be involved, appropriate ergonomic training and clear responsibilities. Addressing key facilitators and barriers such as programme support, resources, and communication is paramount.

Statement of Relevance: A recent systematic review has suggested that PE has some effect on reducing symptoms, lost days of work and claims. Systematic reviews of effectiveness provide practitioners with the desire to implement but do not provide clear information about how. This article reviews the literature on process and implementation of PE.     

Activity in neck-shoulder and lower arm muscles during computer and smartphone work

Relevance to industryThere is emerging evidence of musculoskeletal problems related to smartphone work and a rapid transition to mobile workplaces, where smartphones are key working tools. Aim: The study's aim was to compare muscle activity during computer work with smartphone work and to see what possible effects ergonomic recommendations for smartphone usage have on muscle activity.MethodsActivity was measured bilaterally from the upper trapezius muscle and from lower arm muscles on the right hand side, on twelve participants with surface electromyography who performed e-mail work on the computer using ergonomic recommendations, smartphone in a self-chosen way of working and on smartphone with ergonomic recommendations. Effects on productivity was not assessed in this study.ResultsActivity in m. trapezius and m. extensor digitorum was significantly higher during computer work (p < 0.05) than during the two smartphone usages and activity in m. interossei dorsalis 1 was, vice versa, significantly higher during smartphone work (p < 0.05). Comparison of smartphone in self-chosen way of working and smartphone with ergonomic recommendations showed no significant differences.ConclusionsPrevious research has highlighted the benefits of variation of work postures. This paper indicates that replacing the computer with a smartphone gives the trapezius muscle an opportunity to rest.     

Potential of adjustable height carts in reducing the risk of low back injury in grocery stockers

While the workers of the Wholesale and Retail Trade industrial sector suffer from musculoskeletal disorders at an alarming rate, there have been few investigative studies into potential effective interventions to reduce the ergonomic stress. The objective of the study was to determine whether a cart with an adjustable shelf could reduce awkward postures and motions while stocking products in a grocery store. Fifteen workers at a small grocery store in Puerto Rico completed stocking tasks with two types of carts: traditional and adjustable height cart or Ergo Cart. Trunk kinematics, LBD risk index, NIOSH lifting index, subjective ratings, and productivity indicators were collected during four typical stocking tasks. The Adjustable Ergo Cart reduced the sagittal trunk flexion by 7° and velocity by about 5°/s but increased twisting by about 2° and twist velocity by 4°/s as compared to the traditional cart. The LBD risk index was reduced by a small 2.4% in probability although greater reductions were found for larger items (e.g. bags of dog food and 2-L of Soda). The consensus among workers was that the adjustable cart would be easier to use. Overall, the study provides objective evidence that an ergonomically designed cart (e.g. adjustable height) has some potential to reduce sagittal trunk flexion, LBD risk index, and the NIOSH lift index. Overall, the results indicate that any intervention such as an adjustable cart can only have marginal effectiveness unless the entire systems perspective is considered.     

Legal system and its effect for prevention of work-related musculoskeletal disorders in Korea

This study aims to introduce the legislation of occupational safety and health regulations for prevention of WMSDs in Korea and investigate its effect by showing an ergonomic intervention effort in a major motor company. In Korea, WMSDs incidence rates had increased from 1999 to 2003, and it is noted that its increment jumped rapidly in 2002 and 2003. The Korean government established a law prescribing employers’ duty of preventing WMSDs in 2002, which began effective in July, 2003. Following the legislation, all employers should execute the examination of WMSDs risk factors for the eleven designated tasks every three years. In addition to this legal obligation, some large companies voluntarily established an ergonomic intervention program by carrying out in-depth assessments for stressful tasks using OWAS, RULA, NLE, etc. We introduce a major motor company case to illustrate the industry’s activities of fulfilling the legislative requirement and of performing ergonomic assessments. Thanks to Korean government and industry’s effort for prevention of WMSDs, the incidence rates of WMSDs have continually decreased from the year of 2004, right after the year when the WMSDs-related regulation was enforced.

Relevance to industry

In spite of booming of information technology industries and automation of manufacturing processes in Korea, many workers are still exposed to the risk of WMSDs including awkward postures, stressful force exertions, repetitive motions in manufacturing and agriculture industries. WMSDs cases alone constitute 43.1% of occupational diseases in Korea and the industry’s effort of ergonomic intervention of WMSDs becomes a major issue to both the management and the labor union.     

Occupational musculoskeletal and mental health: Significance of rationalization and opportunities to create sustainable production systems – A systematic review

This literature review aims to identify occupational musculoskeletal and mental health effects of production system rationalization as well as organizational-level measures that may improve health outcome (“modifiers” in this review). A short review of the effect of ergonomic interventions is included as background and rationalization is discussed as a theoretical concept. Indicator variables for occupational musculoskeletal and mental health and related risk factors are presented. Variables with a generalized format were allowed in the literature searches (e.g., job satisfaction and absenteeism were accepted as risk factor and health indicator, respectively), suitable for the research fields of work sociology, organization science, human resource management (HRM) and economics research.One hundred and sixty-two studies of rationalization effects on health and risk factors and 72 organization-level modifier results were accepted into the final database. Entries were sorted by rationalization strategy and work life sector, and trends in outcome (positive, mixed, no effect, or negative effect on health and risk factors) were determined.Rationalizations have a dominant negative effect on health and risk factors (57% negative, 19% positive); the most negative effects were found for downsizing and restructuring rationalizations in general (71 studies negative, 13 positive) and for the health care sector in particular (36 studies negative, 2 positive). The rationalization strategy High Performance Work System (HPWS) was associated with the highest fraction positive outcome studies (6 of 10 studies). Other rationalization strategies (lean practices, parallel vs. serial production and mechanization level) reported intermediate results, in part dependent on work life sector, but also on the year when studies were carried out. Worker participation, resonant management style, information, support, group autonomy and procedural justice were modifiers with favourable influence on outcome.It is concluded that production system rationalization represents a pervasive work life intervention without a primary occupational health focus. It has considerable and mostly negative influence on worker health, but this can be reduced by attention to modifiers. The results create a basis for new priorities in ergonomic intervention research.     

Ergonomic interventions among waste collection workers: A systematic review

Waste collection workers are frequently exposed to significant occupational hazards. Even though ergonomic interventions can mitigate these occupational hazards, only a few studies have attempted to study the importance of the interventions. The current review identifies the gaps in ergonomic interventions among waste collection workers. A systematic review and a bibliometric analysis of the literature on the assessment of occupational hazards and ergonomic interventions in different countries were performed to identify the scope of the interventions. A literature search was carried out in Web of Science, PubMed and Scopus for articles published until December 2018. The search yielded seventy articles on the assessment of occupational health and ten articles on ergonomic interventions among waste collection workers. Based on the review, this paper proposes a hierarchical framework for the implementation of ergonomic interventions in waste associated occupations. The problems faced by formal and informal waste collectors are critical, particularly in developing countries and there is a growing need for low-cost interventions. It is suggested that the potential interventions have to be implemented based on the nature of occupational hazard considering social, cultural and economic factors.     

Ergonomic analysis of slip-resistance measurement devices

Several measurement devices and techniques have been developed during the past 50 years in an attempt to quantify the static and/or dynamic coefficient of friction (COF) of shoe and floor surface interfaces. Much of this work has been laboratory research with bulky equipment, but recently portable measurement devices have evolved to the extent that field measurements can be taken. Six such devices, three for static COF (Bigfoot, Slipometer and NBS-Brungraber) and three for dynamic COF (British Portable Skid Tester, TORTUS and FIDO), were tested in laboratory and field studies so that an ergonomic assessment of device performance could be made. Device consistency, repeatability, accuracy and ease of use were examined for a variety of shoe, floor and floor preparation conditions. All of the devices had advantages and disadvantages for field use; these are summarized and recommendations are made for successfully measuring COF values in the field. Application of ergonomic principles can facilitate the selection of which device to use in any given situation.     

Time trends in ergonomic intervention research for improved musculoskeletal health and comfort in Latin America

Studies on ergonomic intervention research aiming at improved musculoskeletal health published in Latin America in the past 20 years were reviewed. The tendencies observed over time in these studies show that interventions carried out are trying to deal with the changes occurring in the production processes in this period. Thus, more participative approaches have been used, involving different parts interested in the process. The previous transversal projects, more focused on the physical aspects of the work, are now substituted by studies including organizational and longitudinal designs. Despite this, some negative or unchanged outcomes have been obtained. Therefore, good quality intervention studies are needed to provide more generalizable data and improve our understanding on planning, implementing and sustaining effective measures for controlling work-related musculoskeletal disorders.     

A checklist for evaluating ergonomic risk factors resulting from awkward postures of the legs, trunk and neck

A one-page checklist for determining the presence of ergonomic risk factors associateed with awkward postures of the lower extremities, trunk and neck was developed and evaluated as part of a joint labor-management ergonomics intervention program. This checklist was used by plant personnel at four work sites to assess the postural requirements on 335 cyclical (i.e., work-cycle duration less than five minutes) manufacturing and warehouse jobs. In addition, results generated by the checklist were compared to the results of ergonomic analyses performed by persons with advanced training in occupational ergonomics.

Workers were observed using awkward postures for most of the jobs in the survey. Awkward postures of the lower extrimities were relatively uncommon, occuring in 25 percent or less of the jobs. Awkward postures of the trunk and neck were common, occuring in more than 70 percent of the jobs. Results generated by the checklist were generally in agreement with results generated by the experienced ergonomists; however, the checklist was found to be more sensitive in identifying the presence of awkward postures.

The checklist was found to be an effective rapid-screening instrument for identifying cyclical jobs that expose workers to potentially harmful postures. However, the checklist methodology did not include sufficient documentation of work methods to identify the specific job attributes associated with these exposures. Furthermore, the checklist was not used to evaluate non-cyclical jobs (e.g., maintenance and skilled trades).     

Evaluation of ergonomic approach and musculoskeletal disorders in two different organizations in a truck assembly plant

The aim of this study was to assess the ergonomic physical exposure, organizational and psychosocial factors in a truck assembly plant for two different cycle times (11 min and 8 min). A self-reported questionnaire was applied to evaluate subjective physical exposure, organizational and psychosocial factors by operators in two organization of an assembly process. The initial cycle time was 11 min (system A) and the new was 8 min (system B). The same work and assembly tasks had to be completed in both systems. However, the organization and distribution of the tasks and workstations were reorganized. The results of the questionnaire showed that subjective estimation by the operators regarding ergonomic risk factors was better in the new organization and self-reported WR-MSDs symptoms were fewer. However, exposure to risk factors and WR-MSDs symptoms was not statistically different between two cycle times. The findings provide better understanding of how organizational changes can modify ergonomic exposure in manufacturing assembly industries. Effective interventions are thus not only engineering solutions but also organizational and administrative adaptations.