Prognostic factors for the effects of two interventions for work-related neck-shoulder complaints: myofeedback training and ergonomic counselling

AIM: To explore prognostic factors for the effects of two interventions (myofeedback training in combination with ergonomic counselling (Mfb/EC) and ergonomic counselling alone (EC)) on discomfort and disability in work-related neck-shoulder complaints. METHODS: Thirty-six females completed the interventions. Discomfort and disability were assessed at baseline, immediately after the intervention, and at 3-month follow-up. Potential sociodemographic and psychological prognostic factors were assessed using questionnaires. Data were analysed using multiple regression and general linear modelling. RESULTS: Changes in discomfort were best predicted by baseline discomfort levels. Changes in disability were predicted by baseline disability levels, patient profile, and coping strategy 'ignoring sensations'. A significant difference between the Mfb/EC and EC group was found for coping strategy 'ignoring sensations', which appeared to be a predictor for changes in disability at 3-month follow-up in the Mfb/EC group only. CONCLUSIONS: Subjects with high levels of initial discomfort and disability and specific psychological patient profiles benefit most from interventions. Myofeedback training contributes a specific quality to those who ignore pain sensations.     

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

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

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

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

Computer-related posture and discomfort in primary school children: The effects of a school-based ergonomic intervention

This study investigated the effect of a school-based ergonomic intervention on childrens’ posture and discomfort while using computers using a pre/post test study design. The sample comprised 23 children age 9 and 10 years. Posture was assessed with Rapid Upper Limb Assessment (RULA) and a workstation assessment was completed using a Visual Display Unit (VDU) checklist. Self reported discomfort was also recorded at the beginning and end of the computer class. Following an ergonomic intervention that included education of the children and workstation changes, the outcome measures were repeated. There was a positive response to the intervention with significant changes between the pre-intervention and post-intervention scores for posture (p = 0.00) and workstation (p = 0.00). The change in discomfort scores from beginning to end of the computer class between the pre-intervention class and the post-intervention class was also significant (p = 0.00). The study highlights the need for continuing concern about the physical effects of children’s computer use and the implications of school-based interventions.     

A discomfort survey in a poultry-processing plant

The relationship of musculoskeletal pain and discomfort due to awkward work postures, forces, static loading and over-use is widely accepted as an indicator of poor job design. A discomfort survey was conducted in a poultry-processing plant to help to prioritize areas for ergonomics intervention and to determine whether regions of discomfort relate to types of task performed. The survey form was basic, to accommodate illiteracy, and was administered to 699 employees. Demographic data and job information were recorded. The employee rated job satisfaction and overall discomfort, shaded areas of discomfort on a body diagram and rated the intensity of the discomfort for each area. The jobs were coded into four mutually exclusive categories: hand tool, hand manipulation, material handling and mixed task. A discomfort index (DI) combined the number of shaded areas with intensity. Of the 65% who reported discomfort, the back had the highest mean maximum intensity followed by the arm, contrary to prevalence ranking of body regions. In the light of the findings, the benefit of rotation in a plant requiring major redesign is questioned. Results unexpectedly highlighted women who reported arm discomfort with more than one job, and who performed manual material-handling tasks, to have a significant discomfort problem, which indicates the breadth of ergonomics intervention required in the poultry environment. Surprisingly, no other effects of task were found. The survey provided useful indications of ergonomics issues in areas not identified by medical records.     

An investigation of ergonomic interventions in dental hygiene work

Alternative methods for viewing teeth while performing simulated dental procedures were investigated. The methods allowed participants to assume postures requiring less neck flexion than the standard direct view. One alternative used a video camera and monitor to view the mouth, the other incorporated 90 degrees prism glasses. The study was conducted in two parts: (1) novice participants performing a targeting task; (2) dental hygienists performing a scaling task on a mouth model. Posture and subjective perceptions were assessed in Parts 1 and 2. Muscle activity and performance were also assessed in Part 1. The alternative methods significantly reduced muscle activity, neck flexion, and discomfort, compared to the direct view. Preferences were a function of criteria (general, comfort, productivity, or accuracy). Previously, recommendations for reducing ergonomic risk factor exposure of dental professionals emphasized reducing time spent performing dental procedures. This study shows ergonomic interventions offer alternative means of risk exposure reduction.     

University students' notebook computer use: lessons learned using e-diaries to report musculoskeletal discomfort

The objective of this pilot study was to identify if notebook accessories (ergonomic chair, desktop monitor and notebook riser) combined with a wireless keyboard, mouse and participatory ergonomics training would have the greatest impact on reducing self-reported upper extremity musculoskeletal discomfort in university students. In addition to pre-post computing and health surveys, the Ecological Momentary Assessment was used to capture change in discomfort over time using a personal digital assistant (PDA) as the e-diary. The PDA was programmed with a survey containing 45 questions. Four groups of university students were randomised to either intervention (three external computer accessories) or to control. Participants reported less discomfort with the ergonomic chair and notebook riser based on the pre-post survey data and the e-diary/PDA ANOVA analysis. However, the PDA data, adjusted for the effect of hours per day of computer use, showed no benefit of the chair and limited benefit from the riser. Statement of Relevance:University students' use of notebook computers has increased. This study found evidence of a positive effect of an adjustable chair or notebook riser when combined with ergonomic training on reducing discomfort. Daily notebook computer use of 4?h was confirmed as a risk factor. Without some form of ergonomic intervention, these students are likely to enter the workforce with poor computing habits, which places them on the road to future injuries as technology continues to play a dominant role in their lives.     

Impact of multimodal feedback on simulated ergonomic measurements in a virtual environment: A case study with manufacturing workers

The purpose of this study was to evaluate the impact of multimodal feedback on ergonomic measurements in a virtual environment (VE) for a typical simulated drilling task. In total, sixty male manufacturing industry workers were divided into five groups. One group performed the working task in a real environment (RE), and ergonomic measurements for this group were used as the baseline for evaluation. The other four groups performed the same task in a virtual environment with different feedback treatments (visual with or without auditory and/or tactile feedback). Five indices – task completion time, maximum force capacity reduction, body part discomfort, rated perceived exertion, and rated task difficulty – were used to evaluate the measurements of each of the four treatments in VE in comparison to the baseline group in RE. The results indicate that the five indices for each of the four treatment groups were significantly higher than those of the RE group. Moreover, the indices of the visual‐only group were significantly higher than those of the other three groups with auditory and/or tactile feedback treatments. The findings of this study can provide a guideline for ergonomic evaluations of work designs in VE and for establishing a virtual reality simulation system. © 2011 Wiley Periodicals, Inc.     

Fault Diagnosis Training for Maintenance Personnel

The objective of this pilot study was to identify if notebook accessories (ergonomic chair, desktop monitor and notebook riser) combined with a wireless keyboard, mouse and participatory ergonomics training would have the greatest impact on reducing self-reported upper extremity musculoskeletal discomfort in university students. In addition to pre-post computing and health surveys, the Ecological Momentary Assessment was used to capture change in discomfort over time using a personal digital assistant (PDA) as the e-diary. The PDA was programmed with a survey containing 45 questions. Four groups of university students were randomised to either intervention (three external computer accessories) or to control. Participants reported less discomfort with the ergonomic chair and notebook riser based on the pre-post survey data and the e-diary/PDA ANOVA analysis. However, the PDA data, adjusted for the effect of hours per day of computer use, showed no benefit of the chair and limited benefit from the riser.

Statement of Relevance:University students' use of notebook computers has increased. This study found evidence of a positive effect of an adjustable chair or notebook riser when combined with ergonomic training on reducing discomfort. Daily notebook computer use of 4 h was confirmed as a risk factor. Without some form of ergonomic intervention, these students are likely to enter the workforce with poor computing habits, which places them on the road to future injuries as technology continues to play a dominant role in their lives.     

Evaluation of musculoskeletal health outcomes in the context of job rotation and multifunctional jobs

Higher physical demands at work are associated with health outcomes such as discomfort, disorders and sick leave. Variations in work exposure patterns, introduced by multifunctional jobs and ergonomic interventions, bring confounders into the complex relation between occupational risks and musculoskeletal disorders. This study compared whole-body rating of perceived exertion (RPE), discomfort, ergonomic workplace analysis (EWA) and sick leave due to musculoskeletal disorders, among workers exposed to diversified work. The results showed that EWA performed by the observer differed from workers' ratings. There were no differences between groups of workers taking or not taking sick leave regarding RPE and discomfort at their current workstations. Workers significantly discriminated between progressive workload levels, and RPE scores for specific tasks were nonlinear during shifts. These differences might be associated with exposure variability. Thus, in the context of diversified work, the RPE scale seems more appropriate for evaluating acute effects of work variability.     

Ergonomic factors on task performance in laparoscopic surgery training

This paper evaluates the effect of ergonomic factors on task performance and trainee posture during laparoscopic surgery training. Twenty subjects without laparoscopic experience were allotted into 2 groups. Group 1 was trained under the optimal ergonomic simulation setting according to current ergonomic guidelines (Condition A). Group 2 was trained under non-optimal ergonomic simulation setting that can often be observed during training in a skills lab (Condition B). Posture analysis showed that the subjects held a much more neutral posture under Condition A than under Condition B (p < 0.001). The subjects had less joint excursion and experienced less discomfort in their neck, shoulders, and arms under Condition A. Significant difference in task performance between Conditions A and B (p < 0.05) was found. This study shows that the optimal ergonomic simulation setting leads to better task performance. In addition, no significant differences of task performance, for Groups 1 and 2 using the same test setting were found. However, better performance was observed for Group 1. It can be concluded that the optimal and non-optimal training setting have different learning effects on trainees’ skill learning.     

The effect of shoulder posture on performance,discomfort and muscle fatigue whilst working on a visual display unit

An investigation was conducted to determine the relationship between posture and performance while working on a VDU. Twenty-one female subjects performed a 20 min choice reaction time task in a within-subject design with shoulder flexion (0° versus 30°) and noise (55 dB versus 75 dB) as factors. Discomfort measures, electromyography (EMG) measures and measures of performance including reaction time and percentage of errors were collected. The results suggested poorer performance in the 30° shoulder flexion posture compared to the 0° shoulder flexion posture (performance index F_1,20 = 3.95, p = 0.061). There was also significantly greater discomfort and fatigue, as indicated by EMG, in the 30° shoulder flexion compared to 0° shoulder flexion (discomfort: F_1,20 = 99.30; p = 0.0001 EMG: F_1,20 = 4.25, p = 0.052). The results of this study provide the most direct evidence that the posture of VDU users can affect their performance at a task. A number of possible mechanisms for posture to affect performance are explored using the data. The utility of data showing the effect of posture on performance data is discussed in terms of financial modelling to justify the cost of ergonomic intervention. Relevance to industryPoor posture whilst working at a VDU has been previously linked with the development of poor health but has not been directly linked with poor performance. This paper provides evidence to show posture can effect VDU performance. This enables organisations to use estimates of performance changes to model the costs of investment in ergonomic interventions.     

The influence of task design on upper limb muscles fatigue during low-load repetitive work: A systematic review

Ergonomic interventions such as increased scheduled breaks or job rotation have been proposed to reduce upper limb muscle fatigue in repetitive low-load work. This review was performed to summarize and analyze the studies investigating the effect of job rotation and work-rest schemes, as well as, work pace, cycle time and duty cycle, on upper limb muscle fatigue. The effects of these work organization factors on subjective fatigue or discomfort were also analyzed. This review was based on relevant articles published in PubMed, Scopus and Web of Science. The studies included in this review were performed in humans and assessed muscle fatigue in upper limbs. 14 articles were included in the systematic review. Few studies were performed in a real work environment and the most common methods used to assess muscle fatigue were surface electromyography (EMG). No consistent results were found related to the effects of job rotation on muscle activity and subjective measurements of fatigue. Rest breaks had some positive effects, particularly in perceived discomfort. The increase in work pace reveals a higher muscular load in specific muscles. The duration of experiments and characteristics of participants appear to be the factors that most have influenced the results. Future research should be focused on the improvement of the experimental protocols and instrumentation, in order to the outcomes represent adequately the actual working conditions.Relevance to industryIntroducing more physical workload variation in low-load repetitive work is considered an effective ergonomic intervention against muscle fatigue and musculoskeletal disorders in industry. Results will be useful to identify the need of future research, which will eventually lead to the adoption of best industrial work practices according to the workers capabilities.     

Biomechanical analysis of peak and cumulative spinal loads during simulated patient-handling activities: a substudy of a randomized controlled trial to prevent lift and transfer injury of health care workers

Back injuries are a serious problem for nursing personnel who perform frequent patient-handling activities. Common prevention strategies include body mechanics education, technique training, and ergonomic interventions such as the introduction of assistive equipment. This investigation assessed and compared the effectiveness of two patient-handling approaches to reducing injury risk. One strategy involved using improved patient-handling technique with existing equipment, and the other approach aimed at eliminating manual patient handling through the use of additional mechanical and other assistive equipment. Both intervention arms received training in back care, patient assessment, and use of the equipment available on their particular wards. An analysis of compliance with interventions and the effects of patient-handling methods on both peak and cumulative spinal compression and shear during various tasks was conducted. Results showed greater compliance with interventions that incorporated new assistive patient-handling equipment, as opposed to those consisting of education and technique training alone. In several tasks, subjects who were untrained or non-compliant with interventions experienced significantly higher peak spinal loading. However, patient-handling tasks conducted with the aid of assistive equipment took substantially longer than those performed manually. This, along with variations in techniques, led to increases in cumulative spinal loading with the use of patient-handling equipment on some tasks. Thus, the use of mechanical assistive devices may not always be the best approach to reducing back injuries in all situations. No single intervention can be recommended; instead all patient-handling tasks should be examined separately to determine which methods maximize reductions in both peak and cumulative lumbar forces during a manoeuver.     

Effect of Physical Ergonomics on VDT Workers' Health: A Longitudinal Intervention Field Study in a Service Organization

This article examines the effect of physical ergonomic work conditions on occupational health in video display terminal (VDT)-intensive work settings. A longitudinal intervention field study was conducted in a catalog retail service organization in the Midwest to explore the impact of ergonomic interventions. There were 3 levels of ergonomic interventions, each adding incrementally to the previous one. The 1st level was ergonomic training for all VDT users accompanied by workstation ergonomic analysis leading to specific customized adjustments (Group C). The 2nd level added specific workstation accessories supplied by Details, Inc. if the analysis indicated a need for them (Group B). The 3rd level added a Steelcase Criterion(tm) 453 Series chair (Group A). Health data were gathered from 80 volunteer participants by administering a survey before (baseline), 6 months after, and 12 months after interventions were put in place. The findings show that neck, back, and shoulders as well as wrists stand out in terms of self-reported musculoskeletal pain in VDT-intensive work. Reductions in self-reported musculoskeletal discomfort were found for all 3 levels of incremental ergonomic interventions. The number of cases showing improvement in health over time was significant for intervention Groups A and B, but not C.     

Are simple feedback interventions involving workplace data associated with better working environment and health? A cluster randomized controlled study among Swedish VDU workers

OBJECTIVE: To test whether feedback and discussion of ergonomic and psychosocial working environment data during 1 short session with individual, groups, or supervisors of VDU workers had effects on (1) the quality of implemented modifications in workplace design, working technique, or psychosocial aspects; (2) psychological demands, decision latitude, and social support; (3) comfort during computer work, emotional stress, and prevalence of musculoskeletal symptoms or eye discomfort. METHODS: Thirty-six workgroups from 9 organizations were randomized to 3 feedback conditions (individual, workgroup, supervisor) or control. Follow-up was 6 months after intervention. Questionnaire data aggregated on the workgroup level were used. RESULTS: Effect (positive) on social support was indicated from feedback to supervisors. Conclusion: Feedback and discussion of ergonomic and psychosocial working environment data with supervisors of white-collar VDU workers may have positive effect on social support measured as a group characteristic. Sources of potential bias are discussed.     

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.     

Barriers to the adoption of ergonomic innovations to control musculoskeletal disorders and improve performance

Despite a growing number of published articles describing studies of ergonomic interventions, little is known about the barriers potential adopters face when deciding whether or not to adopt such innovations. To this end, the purpose of this paper is to examine the barriers identified by potential adopters of ergonomic innovations and compare barriers identified by individuals not interested in adopting to those identified by individuals planning to adopt. Eight hundred forty-eight fresh market vegetable farmers were mailed surveys measuring the adoption of and barriers to the adoption of several ergonomic innovations as part of a multi-year intervention study. Barriers such as cost, lack of information, never having seen the innovation used and not being able to try out the innovation were among the barriers identified. The barriers identified were moderated by whether or not the respondents were likely to adopt. Implications for diffusing ergonomic and safety innovations are discussed.     

Effectiveness of an ergonomic intervention on work-related posture and low back pain in video display terminal operators: A 3 year cross-over trial

This study investigated the effectiveness of a workstation ergonomic intervention for work-related posture and low back pain (LBP) in Video Display Terminal (VDT) workers. 100 VDT workers were selected to receive the ergonomic intervention, whereas 100 were assigned to a control group. The two groups were then crossed-over after 30 months from baseline. Follow-ups were repeated at 5, 12, and 30 months from baseline and then at 6 months following crossover. Outcomes: Work-related posture and LBP point-prevalence using the Rapid Entire Body Assessment method and a Pain Drawing, respectively. The ergonomic intervention at the workstation improved work-related posture and was effective in reducing LBP point-prevalence both in the first study period and after crossover, and these effects persisted for at least 30 months. In conclusion, our findings contribute to the evidence that individualized ergonomic interventions may be able to improve work-related posture and reduce LBP for VDT workers.     

Influence of shoe/floor conditions on lower leg circumference and subjective discomfort during prolonged standing

Many occupations require workers to stand for prolonged periods, which can cause both discomfort and pain. This study examines the effects of different shoe and floor conditions on standing discomfort in the workplace and laboratory. Two experiments were conducted. Experiment 1 enrolled 10 subjects who performed a computer task under two floors and shoe conditions while standing for 4 h in a laboratory. Experiment 2 involved 14 subjects who stood for 4 h throughout their shift on two different floors in a real work situation (i.e., a field experiment). Analytical results demonstrate that floor type and time standing significantly affected subjective ratings for leg discomfort and circumferential shank measurements in both the laboratory and field studies. Shoe condition significantly affected subjective ratings for leg discomfort. We conclude that shoe/floor conditions and prolonged standing influence worker lower extremity discomfort during prolonged standing. These analytical findings suggest that common ergonomic interventions, such as modifying the flooring on which workers stand might some what alleviate leg edema for workers standing for 4 h shifts in laboratory and field settings. Nevertheless, prolonged standing for even 1 h without rest showed negative effects and should be avoided when possible.