Job rotation designed to prevent musculoskeletal disorders and control risk in manufacturing industries: A systematic review

Effectiveness of Sensors-Based Augmented Feedback in Ergonomics to Reduce Adverse Biomechanical Exposure in Work-Related Manual Handling-A Rapid Review of the Evidence

Manual handling is a major risk factor for work-related musculoskeletal disorders and one of the leading causes of disability-adjusted life years globally, necessitating multifaceted risk reduction measures. One potential intervention for manual handling tasks is work technique training assisted by augmented feedback on biomechanical exposures. However, there is a research gap regarding its effectiveness specifically for manual handling tasks in both real work environments and controlled settings, as well as its ability to induce retained reductions in biomechanical exposure. The gap was investigated using a rapid review comprising a literature search using two databases and 11 reviews/overviews to identify studies from the past 20 years, up to studies published by 1 June 2024. Sixteen studies were identified, with 14 of them being of high or moderate methodological quality and were included. Three studies were conducted in real work environments and eleven in controlled settings. Most studies (n = 9) used auditory feedback, followed by vibration feedback (n = 6). In real work environments, the evidence for the effectiveness of sensor-based augmented feedback in reducing biomechanical exposure during administration was considered to be inconsistent and very limited directly after administration. For longer periods after administration, ranging from one week to more than six months, there is currently no evidence demonstrating the effectiveness of the feedback. In controlled settings, there was strong evidence for its effectiveness during and immediately after administration, and limited evidence for effectiveness up to six months post-administration when considering the tasks included in the training. Future research needs are discussed.

Effectiveness of a Goldilocks work intervention to promote musculoskeletal health among industrial workers - A cluster randomized controlled trial

INTRODUCTION

Industrial workers with physically demanding work have increased risk of musculoskeletal pain. The present 12-week Goldilocks Work intervention aimed to organize work among industrial workers to comprise a 'just right' ergonomic balance of physical behaviors (i.e., sit, stand and active) intended to promote musculoskeletal health. The paper investigates the effectiveness of the intervention in reducing low back pain after work.

METHODS

83 workers across 28 workteams in a biotech organization were recruited. Workteams were randomly allocated to receive the intervention or work as usual (control). Intervention workteams implemented the Goldilocks Work planning tool to organize their work tasks towards a predefined 'just right' ergonomic balance (i.e., composition of 60% sitting, 30% standing, 10% active work and hourly task alternation). The primary outcome was low back pain intensity. Secondary outcomes were bodily pain, fatigue, physical exertion, productivity and energy after work measured in the survey, and composition and alternations of physical behaviors measured using wearable sensors.

RESULTS

The intervention was delivered almost as planned, with good quality and high adherence among most workteams. However, the intervention did not change physical behaviors towards the intended 'just right' ergonomic balance. No significant reduction in low back pain (0.07, CI 95%: -0.68; 0.82), bodily pain (0.10, CI 95%: -0.57; 0.76), tiredness (-0.53, CI 95%: -1.24; 0.19), physical exertion (-0.18, CI 95%: -0.83; 0.48), or improvement in energy (0.39, CI 95%: -1.02; 0.23) or productivity (-0.03, CI 95%: -0.77; 0.72) were found.

CONCLUSION

This Goldilocks Work intervention did not promote musculoskeletal health among industrial workers and did not change physical behaviors as intended. Thus, more research is needed into implementation strategies to change physical behaviors during productive work towards an evidence-based 'just right' ergonomic balance.

Workers' compensation injuries in aviation manufacturing in the state of Kansas, 2014-2022

INTRODUCTION

Workers' compensation injuries entail burdensome financial and social costs. This study's objective was to describe cost and frequency of workplace injuries in aviation manufacturing in the state of Kansas using workers' compensation data. Manufacturing incurs more workers' compensation claims in Kansas than any other industry, and aviation contributes more of those claims than any other sub sector.

METHOD

Workers' compensation insurance and reporting are required in the state of Kansas. Data were provided by the Kansas Department of Labor (KDOL) and included all closed workers' compensation claims entailing indemnity and medical costs filed in the state from 2014 to 2022. Cost of claim data were normalized to 2022 U.S. dollars and data were analyzed as a function of percentage and claim cost by body part, type of injury, cause of injury, specific musculoskeletal disorder type, and as a function of age and gender injury rates.

RESULTS

Aviation claims entailed a median total cost of $26,941 and represented 8% of all closed claims filed in the state from 2014 to 2022. The grand total direct cost over the nine-year period was $75,404,147. Medical costs comprised 48.6% of all costs, indemnity 45.0%, and legal 6.4%. The most frequently injured body part was the hand/wrist (35.9%) followed by the shoulder (20.6%), and the most expensive body parts were related to the back. Overexertion (38.6%) was the most common cause followed by repetitive motion (22.8%). Work-related musculoskeletal disorders were the most common type accounting for 67.4% of all claims. Men and workers aged 55-64 incurred slightly higher claim rates than average. A sharp decrease in number of claims closed in 2021 coincided with production shutdowns the previous year related to the Covid-19 pandemic and design issues.

CONCLUSIONS

Aviation manufacturing is a key industry in Kansas and this study is the first known to describe costs and frequencies of workplace injuries in the sector using workers' compensation data.

PRACTICAL APPLICATIONS

This guide to the most problematic and costly injuries in aviation manufacturing helps practitioners prioritize prevention strategies to most effectively reduce workplace injury and helps safety and health practitioners in prioritizing prevention efforts to reduce the most severe and costly aviation manufacturing injuries and illnesses. It also brings attention to some special considerations when working with safety data from 2020 to 2022 related to the Covid-19 pandemic.

Facilitators and Barriers to Implementing Interventions to Prevent Musculoskeletal Disorders in Blue-Collar Workers: A Scoping Review

PURPOSE

Blue-collar workers generally have less healthy lifestyles, poorer health, and a lower life expectancy than white-collar workers. At least in part this may be attributed to their work and working conditions. Employers increasingly provide interventions to improve health and wellbeing and prevent musculoskeletal disorders. However, they often do not reach blue-collar workers. The aim of this scoping review was to identify the facilitators for and barriers to implementing such interventions among blue-collar workers.

METHODS

A scoping review in which the study population of the selected studies consists of blue-collar workers (≥ 18 years old) in paid employment. Furthermore, included studies should report facilitators and barriers to implementing interventions to prevent musculoskeletal disorders. The literature search was conducted in six databases. The resulting studies were extracted with the help of the updated Consolidated Framework for Implementation Research.

RESULTS

15 articles were included; these were reviews, intervention studies, qualitative studies and process evaluations. A main facilitator was a participatory approach, which involves the blue-collar worker in the entire process of defining, developing, and implementing a multidimensional preventive intervention. The main barriers on the worker level were unfavorable worker characteristics and unsupportive behavior/attitudes. The main barriers on the organization level were a culture with a high production standard, a hierarchical culture, inflexible work, and an unsupportive attitude from the employer.

CONCLUSION

This review showed the multifaceted nature of implementation. A tailored implementation plan that involves the stakeholders (including workers) is important.

Biomechanical risk factors and subacromial pain provocation in healthy manufacturing workers

Objectives. Work-related musculoskeletal disorders (MSDs) of the shoulder may manifest subclinically. By combining risk assessment and clinical instruments, it may be advisable to recognize workers who may develop more complex MSDs early. This study aimed to evaluate the relationship between biomechanical risk factors and subacromial pain provocation in healthy manufacturing workers. Methods. A cross-sectional descriptive observational study was carried out with workers in the furniture manufacturing industry. The occupational repetitive action (OCRA) checklist was applied to detect risk factors and three clinical tests used to detect subacromial tissue reactivity: the supraspinatus test, the painful arc test and the Hawkins-Kennedy test. Results. The positivity of the clinical tests is higher in the supraspinatus test, followed by the Hawkins-Kennedy test, and lowest in the painful arc test, for both the right and left shoulders. No significant associations were found with the overall OCRA checklist index or specific biomechanical factors. Conclusion. The biomechanical risk factors and the provocation of subacromial pain reviewed in this study were not found to be related. Other physical tests that are more sensitive and adapted to workers at risk of developing musculoskeletal shoulder disorders should be explored.

A Rapid Review on the Effectiveness and Use of Wearable Biofeedback Motion Capture Systems in Ergonomics to Mitigate Adverse Postures and Movements of the Upper Body

Work-related diseases and disorders remain a significant global health concern, necessitating multifaceted measures for mitigation. One potential measure is work technique training utilizing augmented feedback through wearable motion capture systems. However, there exists a research gap regarding its current effectiveness in both real work environments and controlled settings, as well as its ability to reduce postural exposure and retention effects over short, medium, and long durations. A rapid review was conducted, utilizing two databases and three previous literature reviews to identify relevant studies published within the last twenty years, including recent literature up to the end of 2023. Sixteen studies met the inclusion criteria, of which 14 were of high or moderate quality. These studies were summarized descriptively, and the strength of evidence was assessed. Among the included studies, six were rated as high quality, while eight were considered moderate quality. Notably, the reporting of participation rates, blinding of assessors, and a-priori power calculations were infrequently performed. Four studies were conducted in real work environments, while ten were conducted in controlled settings. Vibration feedback was the most common feedback type utilized (n = 9), followed by auditory (n = 7) and visual feedback (n = 1). All studies employed corrective feedback initiated by the system. In controlled environments, evidence regarding the effectiveness of augmented feedback from wearable motion capture systems to reduce postural exposure ranged from strong evidence to no evidence, depending on the time elapsed after feedback administration. Conversely, for studies conducted in real work environments, the evidence ranged from very limited evidence to no evidence. Future reach needs are identified and discussed.

Workplace Psychosocial Factors and Their Association With Musculoskeletal Disorders: A Systematic Review of Longitudinal Studies

This systematic review examines literature regarding the relationship between workplace psychosocial factors and musculoskeletal disorders (MSDs). Musculoskeletal disorders are the leading cause of work disability, resulting in billions of dollars of financial losses. Evidence suggests that workplace psychosocial factors can lead to the development and progression of MSDs. A data search was conducted in MEDLINE, EMBASE, PsychINFO, Scopus, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) from August 2009 to May 2020 inclusive. Other eligibility criteria included studies published in English, conducted on adults within a workplace setting, conducted in developed economies, and were stability-control longitudinal observational studies. Studies were independently screened for eligibility, using COVIDENCE (software for managing and streamlining systematic reviews) and assessed for quality by multiple authors, using the JBI Evidence synthesis tool. From 6,812 studies, 47 articles were included in the final analysis. The most common MSDs investigated were lower back pain, neck and shoulder pain, and upper extremity symptoms and disorders. Included articles identified that psychosocial workplace factors of support, collaboration, job control, and job demands were statistically significantly associated with risk and progression of MSDs. Review of the articles included in this article supports the theory that MSDs have a multifactorial, complex etiology that includes psychosocial factors. Interventions to enhance psychosocial work environment provide opportunities to reduce the risk of MSDs.

Assessing the efficacy of a job rotation for improving occupational physical and psychosocial work environment, musculoskeletal health, social equality, production quality and resilience at a commercial laundromat: protocol for a longitudinal case study

INTRODUCTION

Job rotation is a work organisation strategy used to reduce work-related exposures and musculoskeletal complaints, yet evidence for the efficacy of the approach is weak. Mismatch between job rotation and company needs, lack of full implementation, lack of exposure variation in included tasks and failure to assess variation may underlie inconclusive research findings to date. The study aims to develop a job rotation with company stakeholders, perform a process evaluation of the implementation, and determine the extent to which the intervention improves the physical and psychosocial work environment, indicators of health, gender and social equality among workers and production quality and resilience.

METHODS AND ANALYSIS

Approximately 60 production workers at a Swedish commercial laundromat will be recruited. Physical and psychosocial work environment conditions, health, productivity and gender and social equality will be assessed pre and post intervention, using surveys, accelerometers, heart rate, electromyography and focus groups. A task-based exposure matrix will be constructed, and exposure variation estimated at the level of the individual worker pre and post intervention. An implementation process evaluation will be conducted. Job rotation efficacy will be assessed in terms of improvement in work environment conditions, health, gender and social inequality, and production quality and resilience. This study will provide novel information on the effects of the job rotation on physical and psychosocial work environment conditions, production quality and rate, health and gender and social inequality among blue-collar workers in a highly multicultural workplace.

ETHICS AND DISSEMINATION

The study received approval from the Swedish Ethical Review Authority (reference number 2019-00228). The results of the project will be shared directly with the employees, managers and union representatives from the participating company, other relevant labour market stakeholders and with researchers at national and international conferences and via scientific publication.

TRIAL REGISTRATION NUMBER

The study is preregistered with the Open Science Framework (https://osf.io/zmdc8/).

Effectiveness of warm-up interventions on work-related musculoskeletal disorders, physical and psychosocial functions among workers: a systematic review

OBJECTIVES

The aim of this systematic review was to identify from published literature the available evidence regarding the effects of warm-up intervention implemented in the workplace on work -related musculoskeletal disorders (WMSDs) and physical and psychosocial functions.

DESIGN

Systematic review.

DATA SOURCES

The following four electronic databases were searched (from inception onwards to October 2022): Cochrane Central Register of Controlled Trials (CENTRAL), PubMed (Medline), Web of Science and Physiotherapy Evidence Database (PEDro).

ELIGIBILITY CRITERIA

Randomised and non-randomised controlled studies were included in this review. Interventions should include a warm-up physical intervention in real-workplaces.

DATA EXTRACTION AND SYNTHESIS

The primary outcomes were pain, discomfort, fatigue and physical functions. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and used the Grading of Recommendations, Assessment, Development and Evaluation evidence synthesis. To assess the risk of bias, the Cochrane ROB2 was used for randomised controlled trial (RCT) and the Risk Of Bias In Non-randomised Studies-of Interventions was used for the non-RCT studies.

RESULTS

Three studies met the inclusion criterion, one cluster RCT and two non-RCTs. There was an important heterogeneity in the included studies principally concerning population and warm-up intervention exercises. There were important risks of bias in the four selected studies, due to blinding and confounding factors. Overall certainty of evidence was very low.

CONCLUSION

Due to the poor methodological quality of studies and conflicting results, there was no evidence supporting the use of warm-up to prevent WMSDs in the workplace. The present findings highlighted the need of good quality studies targeting the effects of warm-up intervention to prevent WMSDs.

PROSPERO REGISTRATION NUMBER

CRD42019137211.

Effects of Combining Occupationally Relevant Physical and Cognitive Tasks. A Systematic Review

OBJECTIVES

Physical and cognitive tasks occur together in many occupations. Previous reviews of combined tasks have mainly focused on their effects in a sports context. This review investigated to which extent combinations (concurrent or alternating) of occupationally relevant physical and cognitive tasks influence responses reflecting biomechanical exposure, stress, fatigue, performance, and well-being.

METHODS

We searched Scopus, Pubmed, Cinahl, and Psychinfo for controlled experiments investigating the effects of combinations of occupationally relevant physical and cognitive tasks in participants aged 18 to 70. In total, we identified 12 447 records. We added recent papers that had cited these studies (n = 573) to arrive at a total of 13 020 publications. After screening for relevance, 61 studies remained, of which 57 were classified to be of medium or high quality. Of the 57 studies, 51 addressed concurrent tasks, 5 alternating tasks, and 1 both concurrent and alternating tasks.

RESULTS

Most studies of concurrent physical and cognitive tasks reported negative effects, if numerically small, on indicators of biomechanical exposure, fatigue, and performance, compared to a physical task alone. Results were mixed for stress indicators, and well-being was too little studied to justify any conclusions. Effects depended on the tasks, including their intensity and complexity. Alternating physical and cognitive tasks did not appear to influence outcomes much, compared to having passive breaks in-between physical tasks.

CONCLUSIONS

The reviewed evidence indicated that concurrent physical and cognitive work tasks have negative, yet small effects on biomechanical indicators, fatigue and performance, compared to performing the physical task alone, but only if the physical task is intense, and the cognitive task is complex. Alternating between physical and cognitive tasks may have similar effects as breaking up physical tasks by passive breaks, but studies were few. Future studies should address ecologically valid combinations of physical and cognitive tasks, in particular in controlled field studies devoted to the long-term effects of combined work.

Using a Back Exoskeleton During Industrial and Functional Tasks-Effects on Muscle Activity, Posture, Performance, Usability, and Wearer Discomfort in a Laboratory Trial

OBJECTIVE

To investigate the effect of using a passive back-support exoskeleton (Laevo V2.56) on muscle activity, posture, heart rate, performance, usability, and wearer comfort during a course of three industrial tasks (COU; exoskeleton worn, turned-on), stair climbing test (SCT; exoskeleton worn, turned-off), timed-up-and-go test (TUG; exoskeleton worn, turned-off) compared to no exoskeleton.

BACKGROUND

Back-support exoskeletons have the potential to reduce work-related physical demands.

METHODS

Thirty-six men participated. Activity of erector spinae (ES), biceps femoris (BF), rectus abdominis (RA), vastus lateralis (VL), gastrocnemius medialis (GM), trapezius descendens (TD) was recorded by electromyography; posture by trunk, hip, knee flexion angles; heart rate by electrocardiography; performance by time-to-task accomplishment (s) and perceived task difficulty (100-mm visual analogue scale; VAS); usability by the System Usability Scale (SUS) and all items belonging to domains skepticism and user-friendliness of the Technology Usage Inventory; wearer comfort by the 100-mm VAS.

RESULTS

During parts of COU, using the exoskeleton decreased ES and BF activity and trunk flexion, and increased RA, GM, and TD activity, knee and hip flexion. Wearing the exoskeleton increased time-to-task accomplishment of SCT, TUG, and COU and perceived difficulty of SCT and TUG. Average SUS was 75.4, skepticism 11.5/28.0, user-friendliness 18.0/21.0, wearer comfort 31.1 mm.

CONCLUSION

Using the exoskeleton modified muscle activity and posture depending on the task applied, slightly impaired performance, and was evaluated mildly uncomfortable.

APPLICATION

These outcomes require investigating the effects of this passive back-supporting exoskeleton in longitudinal studies with longer operating times, providing better insights for guiding their application in real work settings.

New work situations call for familiar work design methods: Effects of task rotation and how they are mediated in a technology-supported workplace

New digital assistive technologies strive to alleviate the completion of work tasks but thereby often threaten to make jobs increasingly monotonous. To counteract jobs becoming more and more monotonous, task rotation might be an appropriate technology feature. However, it is uncertain whether task rotation has unique positive effects, why it works, and whether there are any boundary conditions. To investigate this, we conducted two experimental vignette studies. In Study 1 (N₁ = 135), we drew on the job characteristics model and self-determination theory to examine perceived task variety, skill variety, and task identity, and expected satisfaction of the need for competence as mediators of the effect of task rotation on anticipated employee attitudes (job satisfaction, intrinsic work motivation), behavior (subjective performance), and well-being (positive and negative affect). The investigated vignette described a job where a digital assistance system either indicated the task rotation or only supported work steps. Regression analyses showed direct effects of task rotation on expected job satisfaction, intrinsic motivation, and positive affect. There were indirect effects of task rotation on all outcomes except expected negative affect. We used Study 2 (N₂ = 159) as an exact replication of Study 1. Additionally, to investigate the boundary conditions of task rotation effects, we drew on person-job fit theory and investigated openness to experience as a moderator of the effects of task and skill variety on the outcomes. Regression analyses showed direct effects of task rotation on expected job satisfaction, subjective performance, and positive affect. There were indirect effects of task rotation on all outcomes except expected negative affect and intrinsic motivation. Thus, the results of Study 1 could only be partly replicated. Openness to experience did not moderate the effects of task and skill variety on the outcomes. The results support the relevance of task rotation as a technology feature and indicate that rotations should offer especially skill variety and task identity, as these were the strongest mediators in our studies.

Social Sustainability in Production Planning: A Systematic Literature Review

Sustainable production includes economic, environmental, and social aspects. However, social sustainability has received less attention, especially compared to the economic aspects. Next to technical and organizational measures, social improvements within supply chains can also be achieved through suitable production planning. Within production planning, production programs are determined, and the assignment of available resources (e.g., employees) is specified. Thus, the utilization and workload of employees are defined. This systematic literature review investigates to what extent such employee-related social aspects are reflected in production planning and discusses whether economic aspects dominate them. For this, a Scopus database search was carried out and 76 identified approaches were analyzed and categorized regarding the occurring employee-related social aspects and their implementation. Thus far, the approaches mainly consider single aspects on single planning levels. A consideration of a broad set of aspects along the entire production planning has rarely been studied. In particular, health and safety aspects are considered on the levels of assembly line balancing and job rotation. However, their impact is primarily determined by the specific settings of the decision-maker. To support decision-makers, only a few studies have investigated the effects based on real application scenarios. Further potential might be an extended modeling of social and economic interdependencies and a consideration of employee-related social aspects in medium- to long-term production planning.

A genetic algorithm approach to design job rotation schedules ensuring homogeneity and diversity of exposure in the automotive industry

Job rotation is a work organization strategy with increasing popularity, given its benefits for workers and companies, especially those working with manufacturing. This study proposes a formulation to help the team leader in an assembly line of the automotive industry to achieve job rotation schedules based on three major criteria: improve diversity, ensure homogeneity, and thus reduce exposure level. The formulation relied on a genetic algorithm, that took into consideration the biomechanical risk factors (EAWS), workers' qualifications, and the organizational aspects of the assembly line. Moreover, the job rotation plan formulated by the genetic algorithm formulation was compared with the solution provided by the team leader in a real life-environment. The formulation proved to be a reliable solution to design job rotation plans for increasing diversity, decreasing exposure, and balancing homogeneity within workers, achieving better results in all of the outcomes when compared with the job rotation schedules created by the team leader. Additionally, this solution was less time-consuming for the team leader than a manual implementation. This study provides a much-needed solution to the job rotation issue in the manufacturing industry, with the genetic algorithm taking less time and showing better results than the job rotations created by the team leaders.

An exploratory study comparing three work/rest schedules during simulated repetitive precision work

The pattern of work and rest can influence both physical fatigue and task performance in manual operations. However, there is relatively limited evidence regarding the influences of specific work/rest schedules in tasks requiring high repetitiveness and precision demands, along with relatively low exertion levels. Eighteen participants completed an exploratory study that simulated such tasks, to compare the effects of three distinct work/rest schedules (i.e. short frequent [short] and long infrequent breaks [long], and a self-selected schedule) on muscle fatigue, task performance (in terms of accuracy and speed), and preference. Schedules with long or self-selected breaks generally induced less muscle fatigue, compared with the short break condition. Participants preferred the self-selected condition the most and the long-break condition the least. The different schedules tested did not influence task performance. A self-selected schedule may be beneficial for repetitive precision task, to achieve a balance across muscle fatigue, task performance, and individual preference. Practitioner summary: Influences of three work/rest schedules (i.e. short and long breaks, and a self-selected schedule) on fatigue, performance, and preference were explored during repetitive precision tasks. Schedules with long or self-selected breaks induced less muscle fatigue and none of the three schedules influenced performance. A self-selected schedule was the most preferred.

Relationship between job rotation and work-related low back pain: a cross-sectional study using data from the fifth Korean working conditions survey

Background

Job rotation was introduced in various industries as a strategic form of work for improving workers' job skills and health management. This study aims to examine the relationship between job rotation and work-related low back pain (LBP), one of the typical work-related musculoskeletal symptoms of Korean workers.

Methods

We conducted this study using the data of the 5th Korean Working Conditions Survey (KWCS). As the subject of this study, 27,163 wage workers were selected, and classified into three groups according to occupational type (white-collar, service and sales, and blue-collar). In this study, job rotation means to change the work-related activities with other colleagues periodically and work-related LBP was defined as whether there was work-related LBP in the last 12 months. Chi-square test and logistic regression were used to analyze the relationship between job rotation and work-related LBP.

Results

Out of 27,163 workers, 2,421 (8.9%) answered that they had job rotation and 2,281 (8.4%) answered that they experienced work-related LBP. According to the results from logistic regression, job rotation was significantly associated with low prevalence of work-related LBP among blue-collar workers (odds ratio [OR]: 0.71, 95% confidence interval [CI]: 0.58–0.88), whereas no significant relationship was observed among white-collar, service and sales groups. In addition, the negative association between job rotation and work-related LBP among blue-collar workers was more pronounced when exposed to ergonomic risk factors (uncomfortable posture OR: 0.79, 95% CI: 0.64–0.98; heavy work OR: 0.74, 95% CI: 0.57–0.96; repetitive work OR: 0.74, 95% CI: 0.60–0.92).

Conclusions

Job rotation was associated with low prevalence of work-related LBP among workers in the blue-collar occupational group in Korea. It is necessary to evaluate the effect of job rotation by occupational type and introduce an appropriate method of job rotation to reduce workers' work-related musculoskeletal symptoms.

Fatigue, Stress, and Performance during Alternating Physical and Cognitive Tasks-Effects of the Temporal Pattern of Alternations

In occupational life, performing cognitive work tasks in between fatiguing physical work tasks may allow recovery and reduce stress without losing productive working time. The temporal pattern of such alternations is likely a determinant of the recovery effect, influencing both stress and fatigue; the difficulty of the cognitive task (CT) would also be a likely determinant. The aim of this study was to determine to what extent the temporal pattern of alternations between a repetitive physical task and a CT of different difficulties influenced perceived fatigability, performance fatigability, stress-related outcomes, and performance. Fifteen women performed four work sessions comprising 110 min of repeated bouts of a repetitive physical task (pipetting), alternating with a CT (n-back). Sessions differed in bout cycle time (short: 7 + 3 min versus long: 14 + 6 min) and CT difficulty (CTdiff; easy versus difficult). Fatigue was assessed from recordings of maximal voluntary contraction force in shoulder elevations and handgrip pre- and post-work, electromyography (EMG) from the right trapezius and right forearm extensors during work, and repeated self-ratings of fatigue and pain throughout the session. Stress was assessed using electrocardiography (heart rate variability), salivary alpha-amylase, and self-reports. Perceived fatigue increased significantly over time for all protocols and more in long-cycle than short-cycle conditions. EMG activity did not increase markedly over time in any condition. Neither objective nor subjective indicators suggested that stress increased over time, regardless of the temporal pattern. Pipetting performance remained stable in all conditions. Cognitive performance, measured by the proportions of correct positive and false positive answers, differed between CTdiff levels but remained stable over time, with no significant difference between temporal patterns. In summary, temporal patterns of alternating tasks influenced fatigue to some extent but had no obvious influence on stress indicators or performance. Thus, designing job rotation with alternating physical and cognitive work should consider the temporal patterns of alternations to minimize fatigue.

Osteopathic model of the development and prevention of occupational musculoskeletal disorders

Context

The direct and indirect costs of work-related musculoskeletal disorders are significant. Prevention is the most effective way to control these costs. To do that, we must understand how these disorders develop.

Objectives

To use the five models of osteopathic care to illustrate how cellular processes and neural reflexes interact to create work-related musculoskeletal pathology and to provide evidence-informed musculoskeletal injury and disability prevention recommendations.

Methods

A literature review of electronic databases (Google Scholar, PubMed, OVID, Cochrane Central Register of Controlled Trials, PEDro, and OSTMED.DR) from inception to October 16, 2019 and hand-search of publication references was performed for systematic reviews, cohort studies, case-control studies, and randomized controlled trials. The search terms reflected topics related to occupational injury and injury prevention, and included supplementary laboratory studies and narrative reviews related to the biological aspects of musculoskeletal injury. The eligible studies contained the following criteria: (1) the population of working age; (2) exposures to known risk factors, musculoskeletal disorders, and psychosocial factors; (3) written in English; (4) full text papers published in peer-reviewed journals; and (5) systematic review, cohort study, case-control study, and randomized controlled trial methodology. Studies were excluded if they included outcomes of productivity and costs only or outcomes that were assessed through qualitative methods only.

Results

The literature search resulted in 1,074 citations; 26 clinical studies and 14 systematic reviews were used in this review. A comprehensive workplace musculoskeletal disorder prevention program should match demands to capacity, correct dysfunctional movement patterns, and limit tissue vulnerability (biomechanical-structural model); restore alpha-gamma balance, tonic-phasic synergistic function, and autonomic balance (neurological model); maximize physiologic reserve (metabolic-energy model) component of a prevention program; optimize respiration and circulation (respiratory-circulatory model); and address cognitive distortions (behavioral-biopsychosocial model).

Conclusions

The presented osteopathic model of the development and prevention of work-related musculoskeletal disorders suggests that a combination of preventive interventions will be more effective than any single preventive intervention.

Forces: A Motion Capture-Based Ergonomic Method for the Today's World

Approximately three of every five workers are affected by musculoskeletal disorders, especially in production environments. In this regard, workstation ergonomic evaluations are especially beneficial for conducting preventive actions. Nevertheless, today's context demonstrates that traditional ergonomic methods should lead to smart ergonomic methods. This document introduces the Forces ergonomic method, designed considering the possibilities of inertial motion capture technology and its applicability to evaluating actual workstations. This method calculates the joint risks for each posture and provides the total risk for the assessed workstation. In this calculation, Forces uses postural measurement and a kinetic estimation of all forces and torques that the joints support during movement. This paper details the method's fundamentals to achieve structural validity, demonstrating that all parts that compose it are logical and well-founded. This method aims to aid prevention technicians in focusing on what matters: making decisions to improve workers' health. Likewise, it aims to answer the current industry needs and reduce musculoskeletal disorders caused by repetitive tasks and lower the social, economic, and productivity losses that such disorders entail.

The influence of using exoskeletons during occupational tasks on acute physical stress and strain compared to no exoskeleton - A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis determined the effects of using an exoskeleton during occupational tasks on physical stress and strain compared to not using an exoskeleton.

METHODS

Systematic electronic database searches were performed and the review was prepared according to the PRISMA guidelines. Treatment effects on the predefined outcomes were calculated using standardized mean differences for continuous outcomes in several meta-analyses using Review Manager 5.3. Registration: PROSPERO (CRD42020168701).

RESULTS

63 articles were included in qualitative syntheses and 52 in quantitative, but most of them did not extensively evaluate musculoskeletal stress and strain and the risk of bias was rated high for all included studies. Statistically significant effects of using back, upper-limb, or lower-limb exoskeletons have been observed in the supported body areas (e.g. reduced muscle activity, joint moments and perceived strain). Studies which did not exclusively focus on the supported body area also showed statistically significant effects in the non-supported areas (e.g. changed muscle activity and perceived strain) and in physiological outcomes (e.g. reduced energy expenditure).

CONCLUSIONS

Using an exoskeleton during occupational tasks seems to reduce user's acute physical stress and strain in the exoskeleton's target area. However, impact on workers' health is still unknown, primarily because of missing long-term evaluations under real working conditions. Furthermore, this systematic review highlights a lack of studies (1) following high quality methodological criteria, (2) evaluating various inter-related stress and strain parameters instead of only focusing on one specific, and (3) evaluating non-target body areas instead of only the directly supported body area.

Strategies for the prevention of carpal tunnel syndrome in the workplace: A systematic review

Carpal Tunnel Syndrome (CTS) is one of the most frequently occurring musculoskeletal disorders of the upper limbs. Strategies for preventing CTS in the workplace include interventions such as ergonomics, education, exercise, physical therapy, and occupational health. The purpose of this study was to provide a general overview based on the review of scientific literature regarding strategies used for preventing CTS in working populations. From September to October 2018, the MEDLINE, PUBMED, EMBASE and SCOPUS (1990 to December 2017) databases were searched for evidence. The risk of bias assessment in the selected papers was evaluated using the criteria recommended by The Cochrane Handbook and the methodological quality of the included studies was evaluated using Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields. A total of 11 studies were included in the present review. A total of 1,061 subjects participated in the studies. The quality of the included studies was limited in three studies, appropriate in three studies, good in three studies, and strong in two studies. The overall results suggest a mixed level of evidence of the effect of applying strategies for preventing CTS in the workplace. The bias assessment was primarily due to incomplete result data, selective reporting of results, and blinding. In this review, interventions focused on the modification or change of accessories (keyboard, mouse, wrist rest, and the overall workstation), education in ergonomics, exercise, and physical therapies, among others, were analyzed. The findings of this review show different possibilities when choosing an intervention strategy for the workplace. However, it was challenging to analyze each of the papers owing to the heterogeneity of the studies included.

Task rotation in an underground coal mine: Implications on injury and musculoskeletal discomfort

PURPOSE

To investigate the effect of a task rotation schedule on musculoskeletal injury and the challenges of implementing a task rotation schedule within an underground coal mine.

METHODS

This was a pre-post cross-sectional intervention study with two underground coal mines. Participant-surveys were collected at baseline and 12-months.

RESULTS

There were no significant differences in musculoskeletal discomfort between the two sites in any body region. Tasks were rotated two to three times a shift on average.

CONCLUSIONS

The task rotation schedule did not have a significant impact upon musculoskeletal discomfort although this does not necessarily reflect that the rotation schedule was in-effective in curbing injury, rather highlights the complexity of developing a successful task rotation schedule within an underground coal mine. The task rotation schedule, its implementation and execution need consideration and further investigation to assist in effectively controlling injury and fatigue risk.

Comparing upper arm and trunk kinematics between manufacturing workers performing predominantly cyclic and non-cyclic work tasks

Musculoskeletal disorders (MSDs) are common among manufacturing workers. Exposure to non-neutral postures and high movement speeds associated with MSDs among manufacturing workers may depend on the extent of the variability in the work tasks performed (i.e., predominantly "cyclic" versus "non-cyclic" work). The objectives of this study were to (i) compare mean levels of full-shift exposure summary metrics based on both posture and movement speed between manufacturing workers performing predominantly cyclic (n = 18) and non-cyclic (n = 17) tasks, and (ii) explore patterns of between- and within-worker exposure variance and between-minute (within-shift) exposure level and variation within each group. Inertial sensors were used to measure exposures for up to 15 full shifts per participant. Results indicated (i) substantially higher upper arm and trunk movement speeds among workers performing predominantly cyclic tasks relative to workers performing non-cyclic tasks despite similar postures, and (ii) greater exposure variability both between and within workers in the non-cyclic group.

Personal, biomechanical, psychosocial, and organizational risk factors for carpal tunnel syndrome: a structural equation modeling approach

This longitudinal study aimed at exploring the direct and indirect relationships between organizational, psychosocial, biomechanical, and personal factors and carpal tunnel syndrome (CTS) in French workers. Between 2002 and 2005, 3710 workers were included in the Cosali cohort. Between 2007 and 2010, 1611 workers were re-examined using the same standardized clinical protocol. Subjects free from CTS at baseline were studied (804 men and 563 women). We used structural equation models to examine the relationships between incident CTS cases and organizational (machine-paced work or work pace dependent on customers' demand), psychosocial (job strain model), biomechanical (Borg's rating perceived exertion, wrist bending, pinching, and hand-transmitted vibrations), and personal factors at baseline. Symptomatic CTS risk was directly increased by biomechanical factors (standardized coefficient = 0.19, P = 0.011), female gender (0.25, P < 0.001), and age (0.15, P = 0.042). No psychosocial factors had a direct impact on CTS, but decision authority and skill discretion had an indirect impact by influencing biomechanical exposure. Exposure to machine-paced work had an indirect impact on increasing CTS, either by raising biomechanical exposure (0.19, P < 0.001) or by lowering decision authority (-0.18, P < 0.001) and skill discretion (-0.20, P < 0.001), which in turn increased biomechanical exposure. Similar complex relationships were observed between risk factors and CTS defined by a more strict case definition. Biomechanical exposure had a direct impact on CTS, while organizational factors and psychosocial factors had an indirect impact on CTS. The findings support conceptual models linking work organization to CTS.

More Hype Than Substance? A Meta-Analysis on Job and Task Rotation

Although there exist numerous publications on job and task rotation from various disciplines, there is no consistent evidence of their effectiveness. Drawing on theories from industrial and organizational psychology, knowledge management, ergonomics, and management science, we meta-analytically investigated relationships between job/task rotation and employee attitudes, learning and development, psychological and physical health, and organizational performance. Due to a conceptual overlap and frequent confusion of terminology, we analyzed the design of the rotation (job rotation vs. task rotation) as a possible moderator. The three-level meta-analysis on 56 studies (N = 284,086) showed that rotation was significantly associated with job satisfaction (r = 0.27), organizational commitment (r = 0.16), career success (r = 0.31), labor flexibility (r = 0.32), general psychological health (r = 0.20), stress/burnout (r = -0.13), individual performance (r = 0.13), and productivity (r = 0.13). Positive relationships between rotation and physical health could only be found when rotation was compared to high-intensity work. Task rotation yielded stronger relationships with attitudinal outcomes, job rotation with learning and development, psychological health, and organizational performance outcomes. Further moderator analyses showed that individualism decreased relationships between task rotation and attitudes, and correlations with organizational performance and physical health were stronger for subjective measures. The findings indicate that many expectations toward job and task rotation are not fully supported.

Investigating the Relationship between Body Mass Index and Pain in the Spine in Children or Adolescents: A Systematic Review

Background: Neck pain (NP), back pain (BP), and low back pain (LBP) are generally defined as "pain in the spine." With the increasing prevalence of childhood obesity, secondary problems such as pain in the spine have arisen. The purpose of this review was to investigate the relationship between body mass index (BMI) and pain in the spine in children or adolescents. Methods: Publications were searched in PubMed, Web of Science, Scopus, and Google Scholar databases up to December 12, 2020. The search strategy in the database consisted of free text words and MeSH terms. Results: Twelve studies were reviewed. It was determined that different methods were used in all 12 studies to evaluate pain. In the evaluation of overweight/obesity, these studies performed BMI assessment by dividing body weight in kilograms by height squared. Five studies showed a relationship between LBP and BMI, two studies showed a relationship between BP and BMI, and two studies showed a relationship between NP and BMI. Conclusions: The review shows that there is a relationship between BMI and pain in the spine, especially LBP. There may be factors affecting this condition such as mechanical loading and hormonal metabolic activity in childhood and adolescence. Different methods are used in the studies in literature for the assessment pain in the spine and BMI, overweight, and obesity.

Lean Manufacturing and Ergonomics Integration: Defining Productivity and Wellbeing Indicators in a Human–Robot Workstation

Lean Manufacturing (LM), Ergonomics and Human Factors (E&HF), and Human–Robot Collaboration (HRC) are vibrant topics for researchers and companies. Among other emergent technologies, collaborative robotics is an innovative solution to reduce ergonomic concerns and improve manufacturing productivity. However, there is a lack of studies providing empirical evidence about the implementation of these technologies, with little or no consideration for E&HF. This study analyzes an industrial implementation of a collaborative robotic workstation for assembly tasks performed by workers with musculoskeletal complaints through a synergistic integration of E&HF and LM principles. We assessed the workstation before and after the implementation of robotic technology and measured different key performance indicators (e.g., production rate) through a time study and direct observation. We considered 40 postures adopted during the assembly tasks and applied three assessment methods: Rapid Upper Limb Assessment, Revised Strain Index, and Key Indicator Method. Furthermore, we conducted a questionnaire to collect more indicators of workers’ wellbeing. This multi-method approach demonstrated that the hybrid workstation achieved: (i) a reduction of production times; (ii) an improvement of ergonomic conditions; and (iii) an enhancement of workers’ wellbeing. This ergonomic lean study based on human-centered principles proved to be a valid and efficient method to implement and assess collaborative workstations, foreseeing the continuous improvement of the involved processes.

Ergonomic intervention on a packing workstation with robotic aid -case study at a furniture manufacturing industry

BACKGROUND

Several risk factors among packing lines workers can lead to Work-related Musculoskeletal Disorders (WRMSD) occurrence. Foreseeing WRMSD prevention and productivity increase, some furniture manufacturing industries have been investing in the adoption of robotic solutions. In this field, ergonomics plays an important role to verify if automation implementation has been successful.

OBJECTIVE

This study aims to address the general impact and effectiveness from an ergonomics point of view of the implementation of a robotic aid in a packing workstation.

METHODS

The Nordic Musculoskeletal Questionnaire (NMQ) was applied to 14 workers of semi-automated packing lines. Some additional questions about occupational conditions were included. In order to assess the ergonomic impact of the robotic aid, Rapid Upper Limb Assessment (RULA) was also applied by trained ergonomists, by analyzing the considered packing workstations before and after the adoption of the robotic aid proposed solution.

RESULTS

The results showed that trunk torsion was the most highlighted WRMSD risk factor by all workers, associating it with the lumbar pain. The obtained RULA scores demonstrated that the adoption of a robotic aid eliminated this risk factor and, consequently, reduced the corresponding WRMSD risk.

CONCLUSIONS

The adoption of robotic aids can be instrumental in reducing WRMSD risk in furniture manufacturing industries. Ergonomic studies with workers' participatory approaches seem to be an appropriate strategy to enable the validation and development of industrial robotic solutions.

Development and validation of a cumulative exposure shoulder risk assessment tool based on fatigue failure theory

OBJECTIVE

To present a new risk assessment tool for shoulder intensive occupational tasks based on fatigue failure theory.

METHODS

The tool estimates cumulative damage (CD) based on shoulder moments and loading cycles using an S-N curve derived from in vitro tendon fatigue failure tests. If multiple shoulder tasks are performed, the CD for each is summed. In the validation, 293 workers were evaluated for five separate shoulder outcomes. Logistic regression was used to assess the log CD against five shoulder outcomes adjusted for covariates including age, sex, body mass index (BMI), and plant site.

RESULTS

Both crude and adjusted logistic regression results demonstrated strong dose-response associations between the log CD measure and all five shoulder outcomes (continuous ORs ranged from 2.12 to 5.20).

CONCLUSIONS

The CD measure of The Shoulder Tool demonstrated dose-response relationships with multiple health outcomes. This provides further support that MSDs may be the result of a fatigue failure process.

PRACTITIONER SUMMARY

This study presents a new, easy-to-use risk assessment tool for occupational tasks involving stressful shoulder exertions. The tool is based on fatigue failure theory. The tool was tested against an existing epidemiology study and demonstrated strong relationships to multiple shoulder outcomes.

ABBREVIATIONS

MSD: musculoskeletal disorder; NORA: national occupational research agenda; RULA: rapid upper limb assessment; REBA: rapid entire body assessment; S-N: stress-number of cycles; EDL: extensor digitorum longus; DPC: damage per cycle; CD: cumulative damage; UTS: ultimate tensile strength; FTOV: first time office visit; 3DSSPP: 3-dimensional static strength prediction program; AS: visual analogue scale; BMI: body mass index; CI: confidence interval; Nm: newton-metre; LiFFT: lifting fatigue failure tool; DUET: distal upper extremity tool; OMNI-RES: OMNI resistance exercise scale.

The Implementation of Digital Ergonomics Modeling to Design a Human-Friendly Working Process in a Postal Branch

In today’s business world, there are two very important health issues that the employees in the service sector are faced with: Spinal disease, especially in the lower back, and carpal tunnel syndrome. These are well-known musculoskeletal disorders. To preserve the health of its employees and prevent professional illnesses, and to thus maximize their efficiency, companies must use knowledge from the field of ergonomics. This study aims to examine the work-related health problems that the workers in transportation companies are faced with. As a case study, a postal company from Serbia is considered, with particular attention paid to the counter clerks. The research was carried out in one branch of the postal operator. All six postal clerks working at the considered branch were subjects of the study. The workers were observed visually by the researchers and recorded while performing their job tasks. Based on the analysis of their movements and body positions, the evaluation of their level of risk exposure was determined using the Ergo Fellow software, specifically with five packages within this program (Rapid Upper Limb Assessment, Rapid Entire Body Assessment, Ovako working posture analysis system, Moore and Garg, and Suzanne Rodgers). As a result of the implemented tools, the analysts are in a position to conclude what should be changed in the work organization.

How much do we know about the effectiveness of warm-up intervention on work related musculoskeletal disorders, physical and psychosocial functions: protocol for a systematic review

INTRODUCTION

Work-related musculoskeletal disorders (WMSDs) are a growing worldwide burden and effective interventions to prevent them are needed. Physical activity at the workplace is now recognised as a relevant component of WMSDs prevention. Along these lines, warm-up interventions are now offered in a large number of companies to manage WMSDs. Although benefits of warm-up have been previously documented in sports context, to the best of our knowledge, the effectiveness of such intervention in workplaces still remains to be established. Within this context, the aim of the present review is to identify from published literature the available evidence regarding the effects of warm-up on WMSDs and physical and psychosocial functions.

METHODS

The following electronic databases will be searched (from inception onwards to June 2020): Cochrane Central Register of Controlled Trials, PubMed (Medline), Web of Science and Physiotherapy Evidence Database. Randomised and non-randomised controlled studies will be included in this review. Participants should be adult employees without specific comorbidities. Interventions should include a warm-up physical intervention in real-workplaces. The primary outcomes will be pain, discomfort or fatigue. The secondary outcomes will be job control or motivation at work. This review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and two team members will independently screen all citations, full-text articles and abstract data. A systematic narrative synthesis will be provided with information presented in the text and tables to summarise the characteristics and findings of the included studies.

ETHICS AND DISSEMINATION

The approval of an ethical committee is not required. All the included studies will comply with the current ethical standards. The results of this review will summarise the effects of warm-up intervention on WMSDs, physical or psychosocial functions. This information could help professionals in decision making related to the use of these interventions to prevent WMSDs. Findings will be disseminated to academic audiences through peer-reviewed publications, as well as to policy-makers.

PROSPERO REGISTRATION NUMBER

CRD42019137211.

Stress-Related Responses to Alternations between Repetitive Physical Work and Cognitive Tasks of Different Difficulties

Alternating between physical and cognitive tasks has been proposed as an alternative in job rotation, allowing workers to recover from the physical work while still being productive. However, effects of such alternations on stress have not been investigated. This controlled experiment aimed at determining the extent to which stress-related responses develop during alternating physical and cognitive work, and to determine the extent to which cognitive task (CT) difficulty influences these responses. Fifteen women performed three sessions of 10 consecutive work bouts each including a seven-minute repetitive physical task (pipetting) and a three-minute CT (n-back) at one of three difficulty levels. Stress was assessed in terms of changes in heart rate variability, blood pressure, salivary alpha-amylase, salivary cortisol, perceived stress, and cognitive performance. The work session did not result in any marked stress response, and CT difficulty did not significantly influence stress, apart from alpha-amylase being higher at the easiest CT (F = 5.34, p = 0.02). Thus, according to our results, alternating between repetitive physical tasks and cognitive tasks may be a feasible alternative to classic job rotation between physical tasks only, even if the cognitive task is quite difficult. Future studies should address possible effects of the temporal pattern of alternations, and combine even other occupationally relevant tasks, preferably for extended periods of time.

Occupational Hazards and Health and Safety Risks for Latino Tree Trimmers in the Pine Forest Industry

A pilot project was conducted to evaluate the working conditions and work-related body pain among Latino immigrant tree trimmers (n = 57) in the commercial pine forest service industry. Participants were interviewed about personal and work characteristics, job-related occupational hazards, and body pain. A structured questionnaire and a body pain diagram were used as measures for evaluating associations between personal and work characteristics and body pain. The most common health complaints were physical exhaustion (80.7 percent) and headache (33.9 percent). The reported percent of work-related body pain was 54.4 percent. Statistically significant associations were identified between experiencing body pain in knees, working more than two years, and working more than six hours per day (p < .05) as a tree trimmer. Thorough clinical evaluations are needed to confirm these findings. Future research including a larger sample size and more in-depth evaluations are needed to better evaluate worker tasks, musculoskeletal risk factors, and safety climate issues among this highly vulnerable occupational group.

Effectiveness of a progressive resistance exercise program for industrial workers during breaks on perceived fatigue control: a cluster randomized controlled trial

BACKGROUND

There is strong evidence that physical exercise in the workplace is effective for reducing workers' musculoskeletal complaints. Studies with industrial workers and studies on progressive resistance exercises during breaks are scarce. Our aim was to evaluate the effects of a resistance exercise program on perceived fatigue control among industrial workers.

METHODS

204 employees from the dairy industry were allocated to two groups, the intervention group (IG) (n = 98) and the control group (CG) (n = 106). The primary outcome measures were perceived fatigue control and maximum muscle strength, measured through the Need for Recovery Scale and one-repetition maximum contraction (1-RM), respectively. Secondary outcome measures were musculoskeletal complaints, physical activity level, perceived risk factors, physical fitness (BMI, vital signs, and body fat percentage), and workers´ productivity. All outcomes were assessed at baseline and then again after 4 months. The IG performed resistance exercises using progressively greater loads while the CG performed general exercise using elastic bands. The exercise protocols were performed three times per week for 20 min. An intention-to-treat analysis was performed using the mixed linear model. Results were considered significant when p < 0.05.

RESULTS

The IG did not show to be superior to the CG, although both groups improved perceived fatigue control and muscle strength after the resistance physical exercise program in the worplace. There was also no significant difference between the groups for musculoskeletal complaints and other secondary variables analyzed. However, both groups showed significant improvements between baseline and after 4 months of intervention for all evaluated outcomes (p < 0.05).

CONCLUSION

The implementation of a progressive resistance exercise program during work breaks for perceived fatigue control was no more effective than exercises using elastic bands. However, resistance exercises during work breaks presented better results on all measured outcomes regardless of the exercise protocol used.

TRIAL REGISTRATION

U.S. National Institutes of Health, ClinicalTrials.gov Identifier: NCT02172053. Registered 19 June 2014.

Job rotation and work-related musculoskeletal disorders: a fatigue-failure perspective

Job rotation is an organisational strategy that can be used, in part, to reduce occupational exposure to physical risk factors associated with work-related musculoskeletal disorders (MSDs). Recent studies, however, suggest that job rotation schedules may increase the overall risk of injury to workers included in the rotation scheme. We describe a novel optimisation framework evaluating the effectiveness of a job rotation scheme using the fatigue failure model of MSD development and a case study with real injury data. Results suggest that the effect of job rotation is highly-dependent on the composition of the job pool, and inclusion of jobs with higher risk results in a drastic decrease in the effectiveness of rotation for reducing overall worker risk. The study highlights that in cases when high-risk jobs are present, job redesign of those high risk tasks should be the primary focus of intervention efforts rather than job rotation. Practitioner summary: Job rotation is often used in industry as a method to 'balance' physical demands experienced by workers to reduce musculoskeletal disorder (MSD) risk. This article examines the efficacy of reducing MSDs through job rotation using numerical simulation of job rotation strategies and utilising the fatigue failure model of MSD development.

Designing Cyclic Job Rotations to Reduce the Exposure to Ergonomics Risk Factors

Job rotation is an administrative solution to prevent work-related musculoskeletal disorders that has become widespread. However, job rotation schedules development is a complex problem. This is due to the multi-factorial character of the disorders and to the productive and organizational constraints of the real working environments. To avoid these problems, this work presents an evolutionary algorithm to generate rotation schedules in which a set of workers rotate cyclically over a small number of jobs while reducing the potential for injury. The algorithm is able to generate rotation schedules that optimize multiple ergonomics criteria by clustering the tasks into rotation groups, selecting the workers for each group, and determining the sequence of rotation of the workers to minimize the effects of fatigue. The algorithm reduces prolonged exposure to risks related to musculoskeletal injuries and simplifies the assignment of workers to different tasks in each rotation. The presented procedure can be an effective tool for the design of job-rotation schedules that prevent work-related musculoskeletal disorders while simplifying scheduled changeovers at each rotation and facilitating job monitoring.

Occupational health and ergonomics physiotherapists in Brazil: investigation of the socio-demographic profile and professional practices

Background: Occupational health and ergonomics (OHE) has been recognized as a Physiotherapy specialty in 15 countries; however, a lack of studies that provide profiles of OHE Physiotherapists (PTs) and their professional practices.Objective: To provides a profile of the OHE PTs in Brazil, identify and audit their current professional practices based on the Conselho Federal de Fisioterapia e Terapia Ocupacional (COFFITO) guidelines for this specialty.Method: This was a cross-sectional study. The participants were legally registered with the Regional Council of Physiotherapy and Occupational Therapy (CREFITO) in Brazil. An invitation to participate in the survey was sent to the members of the Association of Physiotherapists in Occupational Health and Ergonomics (ABRAFIT) and PTs recognized for their contributions to the OHE field. The participants were contacted through e-mail, Facebook posts, and LinkedIn messages. The questionnaire was distributed through the SurveyMonkey platform.Results: A total of 153 (86%) OHE PTs returned the survey. The mean age was 35.6 (SD 6.8) years, mean time in the OHE field was 8.5 (SD 5.6) years, the majority are women (61.5%). The OHE PTs were company employees or service providers. The OHE PTs reported satisfaction with their professional performance (74.8%). The OHE PTs' most frequent interventions include biomechanical exposure assessments, ergonomic workplace analysis, and occupational health management.Conclusion: The OHE PTs in Brazil are predominantly women with professional experience who earn higher salaries than other PTs specialties. The OHE PTs based on their audited practices within the COFFITO guidelines focus on ergonomic workplace analysis and biomechanical exposure assessment.

A Game-Theory Method to Design Job Rotation Schedules to Prevent Musculoskeletal Disorders Based on Workers' Preferences and Competencies

Job rotation is an organizational strategy based on the systematic exchange of workers between jobs in a planned manner according to specific criteria. This study presents the GS-Rot method, a method based on Game Theory, in order to design job rotation schedules by considering not only workers' job preferences, but also the competencies required for different jobs. With this approach, we promote workers' active participation in the design of the rotation plan. It also let us deal with restrictions in assigning workers to job positions according to their disabilities (temporal or permanent). The GS-Rot method has been implemented online and applied to a case in a work environment characterized by the presence of a high repetition of movements, which is a significant risk factor associated with work-related musculoskeletal disorders (WMSDs). A total of 17 workstations and 17 workers were involved in the rotation, four of them with physical/psychological limitations. Feasible job rotation schedules were obtained in a short time (average time 27.4 milliseconds). The results indicate that in the rotations driven by preference priorities, almost all the workers (94.11%) were assigned to one of their top five preferences. Likewise, 48.52% of job positions were assigned to workers in their top five of their competence lists. When jobs were assigned according to competence, 58.82% of workers got an assignment among their top five competence lists. Furthermore, 55.87% of the workers achieved jobs in their top five preferences. In both rotation scenarios, the workers varied performed jobs, and fatigue accumulation was balanced among them. The GS-Rot method achieved feasible and uniform solutions regarding the workers' exposure to job repetitiveness.

Evidence of Workplace Interventions-A Systematic Review of Systematic Reviews

Work environment factors are highly correlated with employees' health and well-being. Our aim was to sum up current evidence of health promotion interventions in the workplace, focusing on interventions for the prevention of musculoskeletal disorders, psychological and behavioral disorders as well as interventions for older employees and economic evaluations. We conducted a comprehensive literature search including systematic reviews published from April 2012 to October 2017 in electronic databases and search engines, websites of relevant organizations and institutions. It consisted of simple and specific terms and word combinations related to workplace health promotion based on the search strategy of a previous review. After full-text screening, 74 references met the eligibility criteria. Using the same search strategy, there was a higher proportion of relevant high-quality studies as compared with the earlier review. The heterogeneity of health promotion interventions regarding intervention components, settings and study populations still limits the comparability of studies. Future studies should also address the societal and insurer perspective, including costs to the worker such as lost income and lost time at work of family members due to caregiving activities. To this end, more high-quality evidence is needed.

Alternations between physical and cognitive tasks in repetitive work - effect of cognitive task difficulty on fatigue development in women

In a context of job rotation, this study determined the extent to which the difficulty of a cognitive task (CT) interspersed between bouts of repetitive, low-intensity work (pipetting) influences recovery from fatigue. Fifteen participants performed three experimental sessions, each comprising 10 repeats of a 7 min + 3 min combination of pipetting and CT. The CT was easy, moderate or hard. Surface electromyography (EMG amplitude of the forearm extensor and trapezius muscles) and self-reports was used to assess fatigability. Perceived fatigue and trapezius EMG amplitude increased during sessions. CT difficulty influenced fatigue development only little, besides forearm extensor EMG increasing more in CT3 than in CT1 and CT2. During CT bouts, fatigability recovered, and to a similar extent irrespective of CT. Thus, CT difficulty influenced recovery of perceived as well as performance fatigability to a minor extent, and may not be a critical issue in job rotation comprising alternating physical and cognitive tasks. Practitioner summary: Alternations between physical and cognitive tasks may be an attractive option for job rotation. In this study on women, we show that the difficulty of the cognitive task influences recovery from fatigue only little and we conclude that cognitive difficulty, within reasonable limits, may be a minor issue in job rotation.

Human biomonitoring health surveillance for metals near a waste-to-energy incinerator: The 1-year post-operam study

This human biomonitoring (HBM) follow-up survey, within the SPoTT project, assessed the temporal and spatial trends of exposure to 18 metals in a cohort living around the waste-to-energy (WTE) incinerator of Turin (Italy) before (T0, 2013) and after 1-year of plant activity (T1, 2014). Urine of 380 adult individuals (186 exposed and 194 unexposed subjects, classified on fallout maps) were analyzed by sector field inductively coupled mass spectrometry. A decrease trend of the majority of metals in all subjects indicates that the overall air quality of the studied sites was not significantly compromised, also in proximity of the WTE plant, as corroborated also by air monitoring data of the regional agency. The only relevant exception was the higher Cr levels found at T1 than T0 in exposed subjects, suggesting a possible contribution from the WTE plant. Chromium, Mn and Pt urine levels were also higher in the site far from the WTE, in relation to other sources as vehicular traffic, industrial and civil activities. Whilst, As and Cd were influenced by fish intake and tobacco smoke. A very small number of individuals at T1, equally distributed in both areas, exceeded the health-based guidance values and so, at current knowledge, living near the Turin incineration did not significantly influence the exposure status of the population.

Analysis of Required Investigations of Work-Related Musculoskeletal Disorders in Spain

Musculoskeletal disorders (MSD) are the most common source of occupational health problems in Western countries. In Spain, musculoskeletal disorders (MSDs) can be reported either as accidents or occupational diseases. When reported as an occupational disease, a full diagnosis is performed, as the compensation system needs the approval of the social security authority and a mandatory investigation has to be performed. Although many methods are available for investigating the causes of occupational accidents, occupational diseases have not been analysed with the same depth, and there is a lack of investigation methods. This paper aims to analyse the role of 43 occupational investigations of causes of musculoskeletal diseases in the prevention cycle. This study is based on the occupational investigations performed by workplaces' occupational health and safety specialists when musculoskeletal diseases are reported. The analysis of the data involves descriptive statistics and the Φ coefficient. Based on administrative data, 68 workplaces employing 15,260 workers were surveyed and 41 workplaces with 13,201 workers submitted valid questionnaires to be analysed. The most frequent cause of reported musculoskeletal disease, in terms of primary risk, is repetitive movement. The only proposed measure with a significant association to the exposure by repetitive movements is job rotation (alternating workers between tasks within a job or between activities as a means to vary different levels of exposure). The investigation of occupational diseases has been useful in most of the cases for proposing preventive measures. Most of the workplaces surveyed have performed investigations and adopted preventive measures, but the managers of some workplaces were not aware of any disease notification regarding their workers when surveyed. More research is needed to provide tools for this important task.

Development of an e-health education program at the workplace using formative research - Technologies for improving quality of life

BACKGROUND

e-Learning, a means by which to expand people's access to information can be effective in promoting health in the workplace. This study to present steps in the development of an e-health education program at the workplace.

OBJECTIVE

This study aimed to present all steps of develop a telehealth education program for computer users using formative research to identify themes to health education for workers.

METHODS

A team of expert conducted focus groups with administrative workers (n = 36 participants) to identify thematic health to the development of program. Three meetings were audio video recorded, and notes. All data were based on constant analysis, classical content analysis and keywords in-context.

RESULTS

The content of the nine audio videos included four musculoskeletal health topics (Walking Program, Back School, Muscle Relaxation Techniques, and Work-related Musculoskeletal Diseases); three to healthy diet (Eating and Commensality, Ultra-processed Food and Food labeling, and Oil and Fat); two to mental health (Burnout Syndrome and the Meaning of work).

CONCLUSION

The proposed steps in the development of a workplace e-health education program were successfully achieved. The engagement of the workers' staged focus groups was fundamental to the choice of themes relevant to the population in question.

Radio frequency identification to measure the duration of machine-paced assembly tasks: Agreement with self-reported task duration and application in variance components analyses of upper arm postures and movements recorded over multiple days

Technical advances in inertial measurement units (IMUs) with data logging functionality have enabled multi-day collection of fullshift upper arm postures and movements. Such data are useful for characterizing job-level exposures and, when coupled with task-level information, can inform interventions to mitigate high-exposure tasks. Previously reported methods for capturing task-level information, however, were limited primarily to self-report diaries or direct observation. In this study of machine-paced manufacturing workers (n=6), a low-cost radio frequency identification (RFID) system was used to collect information about when, and for how long, specific assembly tasks were performed during up to 14 consecutive work shifts (76 total work shifts across the six participants). The RFID data were compared to information collected with a self-report diary using Bland-Altman analyses. In addition, the RFID data were paired with IMU data to identify task-level exposures from within full-shift recordings of upper arm postures and movements. These data were then used to estimate the relative contributions of between- and within-worker sources of variance to overall variance in posture and movement summary measures using hierarchical random-effects analysis of variance (ANOVA) techniques. Average estimates of daily task duration based on RFID data were comparable to estimates obtained by self-report (mean bias < ±1 minute) but with substantial variability (limits of agreement > ±100 minutes). In addition, the ANOVA models containing task-level information suggested a substantial amount of the overall exposure variance was attributed to repeated observations of the same task within a work day. These findings (i) suggest that while the RFID system used in this study performed adequately, further refinement, validation, and/or alternative strategies may be needed and (ii) underscore the importance of repeated full-shift and task-based measurement approaches in characterizing physical exposures, even in machine-paced environments.

Variation in upper extremity, neck and trunk postures when performing computer work at a sit-stand station

Sit-stand tables are introduced in offices to increase variation in gross body posture, but the extent to which upper body posture variation is also affected has not previously been addressed. Neck, trunk, and upper arm postures (means and minute-to-minute variances) were determined during periods of sitting and standing from 24 office workers using sit-stand tables to perform computer work. Posture variability resulting from different temporal compositions of sitting and standing computer work was then predicted for the neck, trunk and upper arm by simulations. Postural variability during computer work could be increased up to three-fold when 20-60% of the work was performed standing (i.e. 40-80% performed sitting), compared to performing computer work only sitting. The exact composition of sit-stand proportions leading to maximum variability, as well as the potential size of the increase in variability, differed considerably between workers. Guidelines for sit-stand table use should note these large inter-individual differences.

Quantitative Measures of Physical Risk Factors Associated with Work-Related Musculoskeletal Disorders of the Elbow: A Systematic Review

Background: Work-related musculoskeletal disorders at the elbow are a common health problem, which highly impacts workers’ well-being and performance. Besides existing qualitative information, there is a clear lack of quantitative information of physical risk factors associated with specific disorders at the elbow (SDEs). Objective: To provide evidence-based quantitative measures of physical risk factors associated with SDEs. Methods: Studies were searched from 2007 to 2017 in Medline, EMBASE, and Cochrane Work. The identified risk factors were grouped in main- and sub-categories of exposure using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework for rating evidence. Results: 133 different risk-factor specifications were identified in 10/524 articles and were grouped into 5 main- and 16 sub-categories of exposure. The risk factors were significantly associated with lateral epicondylitis, medial epicondylitis, or ulnar neuropathy. Significant risk factors such as wrist angular velocity (5°/s, with increasing prevalence ratio of 0.10%/(°/s), or forearm supination (≥45° and ≥5% of time combined with forceful lifting) were found. Conclusions: This review delivers a categorization of work-related physical risk-factor specifications for SDEs with a special focus on quantitative measures, ranked for evidence. These results may build the base for developing risk assessment methods and prospective preventive measures.

An Upper Extremity Risk Assessment Tool Based on Material Fatigue Failure Theory: The Distal Upper Extremity Tool (DUET)

OBJECTIVE

Musculoskeletal tissues repeatedly loaded in vitro fail in accordance with material fatigue failure theory, and there is evidence to suggest that the same process occurs in vivo. The current paper presents a new upper extremity risk assessment tool, the Distal Upper Extremity Tool (DUET), predicated on material fatigue failure theory.

METHODS

DUET requires an estimate of force exertion level and the number of repetitions performed to derive estimates of damage and probabilities of experiencing a distal upper extremity outcome. Damage accrued over multiple tasks may be summed to estimate the cumulative damage (CD) accrued over a workday. Validation of this tool was performed using five distal upper extremity (DUE) outcomes (involving medical visits and pain) from an existing epidemiological database involving data from six automotive manufacturing plants. Logistic regression was used to assess the association of the log of the DUET CD measure to DUE outcomes.

RESULTS

Results demonstrated that the log of the DUET CD measure was highly associated with all five DUE outcomes in both crude analyses and those adjusted for site, age, gender, and body mass index ( p < .01). A model relating the continuous DUET log CD score to the probability of the DUE outcome Injury + Pain Last Year was developed, which demonstrated a significant dose-response relationship.

CONCLUSIONS

Results suggest that fatigue failure-based risk assessment techniques are highly associated with DUE outcomes and provide support for the notion that an underlying fatigue failure process may be involved in the development of upper extremity musculoskeletal disorders.

Reliability, Construct Validity and Interpretability of the Brazilian version of the Rapid Upper Limb Assessment (RULA) and Strain Index (SI)

BACKGROUND

There are very few observational methods for analysis of biomechanical exposure available in Brazilian-Portuguese.

OBJECTIVE

This study aimed to cross-culturally adapt and test the measurement properties of the Rapid Upper Limb Assessment (RULA) and Strain Index (SI).

METHODS

The cross-cultural adaptation and measurement properties test were established according to Beaton et al. and COSMIN guidelines, respectively. Several tasks that required static posture and/or repetitive motion of upper limbs were evaluated (n>100).

RESULTS

The intra-raters' reliability for the RULA ranged from poor to almost perfect (k: 0.00-0.93), and SI from poor to excellent (ICC_2.1: 0.05-0.99). The inter-raters' reliability was very poor for RULA (k: -0.12 to 0.13) and ranged from very poor to moderate for SI (ICC_2.1: 0.00-0.53). The agreement was good for RULA (75-100% intra-raters, and 42.24-100% inter-raters) and to SI (EPM: -1.03% to 1.97%; intra-raters, and -0.17% to 1.51% inter-raters). The internal consistency was appropriate for RULA (α=0.88), and low for SI (α=0.65). Moderate construct validity were observed between RULA and SI, in wrist/hand-wrist posture (rho: 0.61) and strength/intensity of exertion (rho: 0.39).

CONCLUSION

The adapted versions of the RULA and SI presented semantic and cultural equivalence for the Brazilian Portuguese. The RULA and SI had reliability estimates ranged from very poor to almost perfect. The internal consistency for RULA was better than the SI. The correlation between methods was moderate only of muscle request/movement repetition. Previous training is mandatory to use of observations methods for biomechanical exposure assessment, although it does not guarantee good reproducibility of these measures.