Ergonomics action research II: a framework for integrating HF into work system design

This paper presents a conceptual framework that can support efforts to integrate human factors (HF) into the work system design process, where improved and cost-effective application of HF is possible. The framework advocates strategies of broad stakeholder participation, linking of performance and health goals, and process focussed change tools that can help practitioners engage in improvements to embed HF into a firm's work system design process. Recommended tools include business process mapping of the design process, implementing design criteria, using cognitive mapping to connect to managers’ strategic goals, tactical use of training and adopting virtual HF (VHF) tools to support the integration effort. Consistent with organisational change research, the framework provides guidance but does not suggest a strict set of steps. This allows more adaptability for the practitioner who must navigate within a particular organisational context to secure support for embedding HF into the design process for improved operator wellbeing and system performance.

Practitioner Summary: There has been little scientific literature about how a practitioner might integrate HF into a company's work system design process. This paper proposes a framework for this effort by presenting a coherent conceptual framework, process tools, design tools and procedural advice that can be adapted for a target organisation.     

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.     

Contextual factors affecting task distribution in two participatory ergonomic interventions: a qualitative study

This article provides an analysis of the evolution of the division of labour in participatory ergonomics (PE) programmes in two worksites. The analysis is based on interviews and field observations in the worksites. In both settings there was meaningful participation by both worker and management members of ergonomic change teams (ECTs) in the hazard assessment and solution identification stages, but as the teams moved to the implementation stage, worker representatives were marginalised and the participatory nature of the programmes was severely curtailed. The removal of workers from the process was the outcome of the interplay among the type of activities pursued in the implementation stage, the skills and knowledge required to carry out those activities, and workers’ limited influence in the organisational hierarchies. Findings highlight the salience of the social context in which participatory programmes are located and the importance of examining participatory programmes as they evolve over time.

Statement of Relevance: This article contributes to a growing literature on the process and implementation of PE programmes. The article's focus on social and organisational factors that affect the division of labour and attention to the evolution of involvement over time extend current understandings of participation in ergonomics programmes.     

A detailed description of the short-term musculoskeletal and cognitive effects of prolonged standing for office computer work

Due to concerns about excessive sedentary exposure for office workers, alternate work positions such as standing are being trialled. However, prolonged standing may have health and productivity impacts, which this study assessed. Twenty adult participants undertook two hours of laboratory-based standing computer work to investigate changes in discomfort and cognitive function, along with muscle fatigue, movement, lower limb swelling and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.47[1.36–1.59]). Sustained attention reaction time (β = 18.25[8.00–28.51]) deteriorated, while creative problem solving improved (β = 0.89[0.29–1.49]). There was no change in erector spinae, rectus femoris, biceps femoris or tibialis anterior muscle fatigue; low back angle changed towards less lordosis, pelvis movement increased, lower limb swelling increased and mental state decreased. Body discomfort was positively correlated with mental state. The observed changes suggest replacing office work sitting with standing should be done with caution.

Practitioner Summary: Standing is being used to replace sitting by office workers; however, there are health risks associated with prolonged standing. In a laboratory study involving 2 h prolonged standing discomfort increased (all body areas), reaction time and mental state deteriorated while creative problem-solving improved. Prolonged standing should be undertaken with caution.     

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

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

Flexible workspace design and ergonomics training: impacts on the psychosocial work environment, musculoskeletal health, and work effectiveness among knowledge workers

A macroergonomics intervention consisting of flexible workspace design and ergonomics training was conducted to examine the effects on psychosocial work environment, musculoskeletal health, and work effectiveness in a computer-based office setting. Knowledge workers were assigned to one of four conditions: flexible workspace (n=121), ergonomics training (n=92), flexible workspace+ergonomics training (n=31), and a no-intervention control (n=45). Outcome measures were collected 2 months prior to the intervention and 3 and 6 months post-intervention. Overall, the study results indicated positive, significant effects on the outcome variables for the two intervention groups compared to the control group, including work-related musculoskeletal discomfort, job control, environmental satisfaction, sense of community, ergonomic climate, communication and collaboration, and business process efficiency (time and costs). However, attrition of workers in the ergonomics training condition precluded an evaluation of the effects of this intervention. This study suggests that a macroergonomics intervention is effective among knowledge workers in office settings.     

A long-term evaluation of the stage of change approach and compensable injury outcomes – a cluster-randomised trial

Abstract

This study investigated the long-term injury outcomes for workers in companies from a range of industries which had been randomly allocated to receive ergonomics interventions tailored according to the stage of change (SOC) approach or standard ergonomics advice. Differences in compensable injury outcomes between the groups were analysed using logistic regression models. Questionnaire results from face-to-face interviews to assess musculoskeletal pain and discomfort (MSPD), job satisfaction and other factors were also analysed. Although not significant at the 0.05 level, after adjusting for workgroup clustering, workers in receipt of tailored advice were 55% (OR = 0.45, 95% CI = 0.19–1.08) less likely to report a compensable injury than those in receipt of standard ergonomics advice. Workload, job satisfaction and MSPD were significantly correlated with injury outcomes. The observed outcomes support the potential value of the SOC approach, as well as highlighting the need to consider workload, job satisfaction and MSPD when planning injury prevention programmes.

Practitioner Summary: This study investigated compensable injury outcomes for workers who had received ergonomics advice tailored according to the stage of change (SOC) approach compared with standard ergonomics advice. The results support the potential value of the SOC approach and highlight the need to consider workload, job satisfaction and musculoskeletal pain and discomfort when planning injury prevention interventions.     

Reducing musculoskeletal disorders among computer operators: comparison between ergonomics interventions at the workplace

Typing is associated with musculoskeletal disorders (MSDs) caused by multiple risk factors. This control study aimed to evaluate the efficacy of a workplace intervention for reducing MSDs among computer workers. Sixty-six subjects with and without MSD were assigned consecutively to one of three groups: ergonomics intervention (work site and body posture adjustments, muscle activity training and exercises) accompanied with biofeedback training, the same ergonomics intervention without biofeedback and a control group. Evaluation of MSDs, body posture, psychosocial status, upper extremity (UE) kinematics and muscle surface electromyography were carried out before and after the intervention in the workplace and the motion lab. Our main hypothesis that significant differences in the reduction of MSDs will exist between subjects in the study groups and controls was confirmed (χ² = 13.3; p = 0.001). Significant changes were found in UE kinematics and posture as well. Both ergonomics interventions effectively reduced MSD and improved body posture.

Practitioner Summary: This study aimed to test the efficacy of an individual workplace intervention programme among computer workers by evaluating musculoskeletal disorders (MSDs), body posture, upper extremity kinematics, muscle activity and psychosocial factors were tested. The proposed ergonomics interventions effectively reduced MSDs and improved body posture.     

Ergonomics action research I: shifting from hypothesis testing to experiential learning

This paper presents the case for the need for ‘Action Research’ (AR) approaches to gain understanding of how ergonomics considerations can best be integrated into the design of new work systems. The AR researchers work collaboratively with other stakeholders to solve a real-world problem: gaining insight into the problem and factors influencing solution building from an embedded position in the development process. This experience is interpreted in terms of available theory and can support further theory development. This non-experimental approach can help provide practical new approaches for integrating ergonomics considerations into real work system design processes. The AR approach suffers from a lack of acceptance by conventionally trained scientists. This paper aims to help overcome this weakness by developing the underlying theory and rationale for using AR approaches in ergonomics research. We propose further development of hybrid approaches which incorporate other evaluation techniques to extend the knowledge gains from AR projects.

Practitioner Summary: Researchers should engage directly with organisations in ergonomics projects so that they can better understand the challenges and needs of practitioners who are trying to apply available scientific knowledge in their own unique context. Such ‘Action Research’ could help develop theory and approaches useful to improve mobilisation and application of ergonomics knowledge in organisations.     

Spreading good ideas: a case study of the adoption of an innovation in the construction sector

A health and safety association collaborated with two research centres to examine the dissemination of knowledge of an ergonomic intervention by opinion leaders in the construction sector. The intervention was a hydraulic ladder lift that aided with loading and unloading of ladders off van roofs. Thirteen companies, with five to 900 employees, were involved. The van operators informed workmates not employed by their companies but who worked on the same site as them about the intervention. The opinion leaders informed decision makers within their companies which led to commitments to purchase similar units. They also gave presentations at prearranged health and safety meetings, where attendees indicated that they thought the intervention sounded like a good idea. In this way, knowledge of the innovation reached at least 32 more companies and potentially several thousand other employees. The study showed the potential for workplace change to be exponential.     

The predictive validity of the RSI QuickScan questionnaire with respect to arm,shoulder and neck symptoms in computer workers

The aim of this study was to determine whether results from the RSI QuickScan questionnaire on risk factors for arm, shoulder and neck symptoms can predict future arm, neck and shoulder symptoms in a population of computer workers. For this prospective cohort study, with a follow-up of 24 months, 3383 workers who regularly worked with a computer were approached. Generalised estimating equations (GEE) with 6, 12, 18 and 24 months time lags were used to determine whether high exposure was related to symptoms at follow-up. The results showed that high scores on 9 out of 13 scales, including previous symptoms, were significantly related to arm, shoulder and neck symptoms at follow-up. These results provide support for the predictive validity of the RSI QuickScan questionnaire.

Practitioner Summary: The results showed that high scores on 9 out of 13 scales, including previous symptoms, were significantly related to arm, shoulder and neck symptoms at follow-up. The RSI QuickScan questionnaire may be recommended as a tool in the identification of computer workers who should be targeted with interventions aimed at prevention of future symptoms.     

A new muscle co-activation index for biomechanical load evaluation in work activities

Low-back disorders (LBDs) are the most common and costly musculoskeletal problem. Muscle co-activation, a mechanism that stabilises the spine, is adopted by the central nervous system to provide added protection and avoid LBDs. However, during high-risk lifting tasks, the compressive load on the spine grows owing to increased co-activation. The aim of this study was to develop a method for the sample-by-sample monitoring of the co-activation of more than two muscles, and to compare this method with agonist–antagonist methods. We propose a time-varying multi-muscle co-activation function that considers electromyographic (EMG) signals as input. EMG data of 10 healthy subjects were recorded while they manually lifted loads at three progressively heavier conditions. The repeated measures ANOVA revealed a significant effect of lifting condition on our co-activation index. Heavier conditions resulted in higher muscle co-activation values. Significant correlations were found between the time-varying multi-muscle co-activation index and other agonist–antagonist methods.

Practitioner Summary: We have developed a method to quantify muscle co-activation during the execution of a lifting task. To do this we used surface electromyography. Our algorithm provides a measure of time-varying co-activation between more than two muscles.     

Manual patient transfers: factors that influence decisions and kinematic strategies employed by nursing aides

While extensive literature has characterised factors that influence the acceptable mass of ‘boxes’ during MMH tasks, less is known about these factors when moving ‘people’ in healthcare settings. This study examined factors that influence decisions/approaches employed during manual patient transfers. Sixteen nursing aides manually-transferred a standardised ‘patient’; patient mass was adjusted (using a weight vest) to determine a maximum acceptable patient mass for this task (mass_max). Grip strength was the only worker characteristic significantly associated with mass_max (r?=?0.48). Older worker age was associated with smaller peak trunk flexion (r?= ?0.58) and shoulder abduction (r?= ?0.59), and greater trunk axial twist (r?=?0.52). Workers emphasised that patient characteristics (e.g. physical/cognitive status) influenced their decisions when performing transfers. These findings extend previous literature by suggesting that grip strength is a useful predictor of perceived work capacity, older workers adapt protective postural strategies during patient transfers and worker-patient dynamics are crucial during this high-risk occupational task.

Practitioner Summary: This study examined manual patient transfers performed by nursing aides. Worker grip strength (but not age or size) was associated with perceptions of maximum acceptable patient mass. Kinematic changes suggested more conservative strategies used by older workers. Workers emphasised that patient characteristics substantially influenced their decisions when performing transfer tasks.     

Dissemination and use of a participatory ergonomics guide for workplaces

Musculoskeletal disorders (MSDs) result in lost-time injury claims and lost productivity worldwide, placing a substantial burden on workers and workplaces. Participatory ergonomics (PE) is a popular approach to reducing MSDs; however, there are challenges to implementing PE programmes. Using evidence to overcome challenges may be helpful but the impacts of doing so are unknown. We sought to disseminate an evidence-based PE tool and to describe its use. An easy-to-use, evidence-based PE Guide was disseminated to workplace parties, who were surveyed about using the tool. The greatest barrier to using the tool was a lack of time. Reported tool use included for training purposes, sharing and integrating the tool into existing programmes. New actions related to tool use included training, defining team responsibilities and suggesting programme implementation steps. Evidence-based tools could help ergonomists overcome some challenges involved in implementing injury reduction programmes such as PE.

Practitioner Summary

Practitioners experience challenges implementing programmes to reduce the burden of MSDs in workplaces. Implementing participatory interventions requires multiple workplace parties to be ‘on-board’. Disseminating and using evidence-based guides may help to overcome these challenges. Using evidence-based tools may help ergonomics practitioners implement PE programmes.     

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

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

Perceived musculoskeletal symptoms among dental students in the clinic work environment

Musculoskeletal symptoms are a major concern among dental practitioners. Dental students perform the same clinical tasks as dentists in private practice, yet only recently has scientific evidence suggested a relationship between the tasks and musculoskeletal symptoms. This study investigates the clinical tasks that place students at physical risk and the relationship between the tasks and musculoskeletal symptoms. Student perceptions of physical symptoms were established with a questionnaire identifying variables on general health, tasks, physical demands, workload and environment. A total of 61% (358/590) reported that during the past year they experienced musculoskeletal symptoms related to work at dental school (second year (n = 212), third year (n = 201) and fourth year (n = 177)). Of those students, the neck represented 48%, shoulder 31%, back 44% and hands 20% (p < 0.001). Third year students reported the highest occurrence of symptoms in every body area (p < 0.001). Third and fourth year students reported significant relationships between the occurrence of symptoms and equipment utilisation, work efficiency and general health. Further studies are recommended to evaluate types and levels of potential risk factors. A total of 75% of dental practitioners are at risk for developing work-related musculoskeletal disorders. Results from this study have found that dental students were no exception. Third year dental students reported the highest level of musculoskeletal symptoms with the prevalence of pain in the neck, shoulder and lower back.     

Task exposures in an office environment: a comparison of methods

Task-related factors such as frequency and duration are associated with musculoskeletal disorders in office settings. The primary objective was to compare various task recording methods as measures of exposure in an office workplace. A total of 41 workers from different jobs were recruited from a large urban newspaper (71% female, mean age 41 years SD 9.6). Questionnaire, task diaries, direct observation and video methods were used to record tasks. A common set of task codes was used across methods. Different estimates of task duration, number of tasks and task transitions arose from the different methods. Self-report methods did not consistently result in longer task duration estimates. Methodological issues could explain some of the differences in estimates seen between methods observed. It was concluded that different task recording methods result in different estimates of exposure likely due to different exposure constructs. This work addresses issues of exposure measurement in office environments. It is of relevance to ergonomists/researchers interested in how to best assess the risk of injury among office workers. The paper discusses the trade-offs between precision, accuracy and burden in the collection of computer task-based exposure measures and different underlying constructs captures in each method.     

Effect of noise on comfort in open-plan offices: application of an assessment questionnaire

Abstract

Open-plan offices account for 60% of French office workspaces. The noise levels recorded in this type of environment are much lower than those encountered in industrial workplaces. Nevertheless, surveys show that noise is considered by employees as the main source of discomfort. A first questionnaire dedicated to noise discomfort was produced in 2013 and tested on a panel made up of 217 people working in 7 French companies. Today, it also makes it possible to address the issues of fatigue related to ambient sound, but above all, the survey aims to study the differences in how ambient noise is perceived depending on the type of open-plan office. On the basis of that new version, a second survey has been conducted in 23 open-plan offices, making it possible to collect the responses from 617 employees. Most of the results of the first survey have been confirmed, with an increase in the significance of the statistical analyses. Moreover, French Standard NF S 31-199, which is currently being drafted, establishes a typology of open-plan office spaces according to the types of work done in them. Based on this typology, it appears that when dealing with the impact on noise on workers, a distinction has to be made between the types of open plan offices.

Practitioner Summary: Surveys conducted in open-plan offices show that noise is considered by employees as the main source of discomfort even if the noise recorded in this type of environment is not hazardous. This work presents the result of a large survey dedicated to noise discomfort conducted in 23 open-plan offices.     

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

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