Musculoskeletal disorders among male sewing machine operators in shoemaking

Research on the relationship between the operation of sewing machines and the appearance of musculoskeletal disorders has been conducted mainly among women working in garment or textile production, in developed countries; little is known about male sewing machine operators in other industries, in less developed countries. This study involved 143 Mexican men operating sewing machines in eight shoe factories; 132 of them operated flat-type machines, 11 column-type machines. When studied, the operators had been in this task for at least one year. The study aimed to identify the body regions more liable to develop musculoskeletal disorders and the rates both of appearance of such troubles and of sick leave resulting from them. A questionnaire was given to each worker, asking for their work history, the presence of musculoskeletal disorders at the time of the inquiry, and the frequency of sick leave during the previous 12 months; additionally, a number of workers were filmed on video and this material was then used to identify the body regions undergoing the major work demands. 47·5% of the subjects declared current musculoskeletal disorders; a statistical difference was found when the two groups were considered separately. Low back pain was the most frequent at a rate of 18·2% for both groups; the shoulder was a site of complaint for 14% of the subjects, being three times more frequent among column-machine operators; the back as a whole was mentioned also by 14% of the subjects, all of them flat-machine operators; 4·9% of the subjects complained of neck pain and again none of the column-machine operators was affected. Only one subject had taken sick leave because of musculoskeletal problems. The body regions affected were those expected from the analysis of the video recordings and were consistent with those reported for occupations involving similar postures and movements. The rates of musculoskeletal complaint found in this study are lower than those reported by other authors who have studied sewing machine operators; taking sick leave is a very rare choice for the workers studied.     

Ergonomic analysis of musculoskeletal discomforts among conversational VDT operators

VDT tasks are rapidly increasing as the office automation prevails. Despite its numerous benefits, occupational hazards such as visual fatigue, eye strain, radiation and musculoskeletal stresses have emerged as an important issue. This study was designed to investigate the effects of work postures and anthropometric differences upon the musculoskeletal stresses experience by operators involved in conversational VDT tasks. Evaluation of the level of muscoloskeletal discomfort was performed for 297 VDT operators from three divisions of telecommunication company in Korea. The ergonomic variables of the VDT tasks and the operators' anthropometric variables were evaluated for 70 out of the 297 VDT operators. Factor analysis is used for identifying underlying pattern of discomfort and multiple regression analysis were performed to examine the relationship between the measured ergonomic variables and the musculoskeletal discomfort. This study indicates that the ergonomic variables have influences on the musculoskeletal discomfort. It is important to provide the workers with fully adjustable workstations so that they can maintain their work postures most suitable for the sustained VDT work. Furthermore, in order to achieve the best working conditions, VDT operators should be given a proper training for the adjustment of their workstations.     

Working hours as a risk factor in the development of musculoskeletal complaints

The length of daily working hours as a risk factor for the development of musculoskeletal complaints was studied by comparing the sick leave statistics of 408 sewing machine operators on full-time schedules (8 h working day) with 210 operators on part-time schedules (5 h working day). Working part-time was shown to postpone the occurrence of sick leave due to musculoskeletal disorders by approximately half a year. There was no lasting effect on the reduction in working hours on sick leave due to shoulder-neck complaints, but a reduction in low back complaints was indicated. It is suggested that any reorganization of work activities to counteract musculoskeletal injuries from repetitive work should aim to break up the muscular activity patterns over time periods considerably shorter than the 5 h working day of the part-time workers in the present study.     

Acceptable muscle load on the neck and shoulder regions assessed in relation to the incidence of musculoskeletal sick leave: Implications for human‐computer interaction

A threshold level for acceptable load on the musculoskeletal system of the neck and shoulder regions was explored by studying comparable groups of female workers with different development of musculoskeletal sick leave in these areas. The load on the neck and shoulder was assessed by recording electromyography (EMG) from m. trapezius (descending part). The quantitative analysis of the trapezius load was carried out by calculating the number and total duration of periods below 5% MVC (Maximum Voluntary Contraction), 8% MVC, and 10% MVC. To relate acceptable musculoskeletal load to health criteria such as acceptable limits for development of musculoskeletal illness in a group of workers, the incidence of musculoskeletal illness for the comparable groups was also compared with a control group of female workers without a continuous work load. Two groups of workers had a development of musculoskeletal sick leave, which was approximately the same as the incidence of such illness for the control group. The trapezius load for these groups was below 5% MVC for about 40% of the working time. By comparing the groups of workers with different development of musculoskeletal sick leave, the trapezius load differed only for load levels below 5% MVC; increasing duration of load levels below 5% MVC was associated with lower incidence of musculoskeletal sick‐leave. The results indicated that trapezius load below 5% MVC was important to reduce the incidence of load‐related musculoskeletal illness.     

An ergonomic evaluation of manual Cleco plier designs: effects of rubber grip, spring recoil, and worksurface angle

The present study evaluated two design modifications (rubber grip and torsion spring) to the conventional manual Cleco pliers by electromyography (EMG), hand discomfort, and design satisfaction. This study also surveyed workers' satisfaction with selected design features of the pliers for ergonomic improvement. A two-way (plier design x worksurface angle) within-subject (nested within gender and hand size) design was employed. Eleven workers simulated the plier task in an adjustable workstation for different plier designs and worksurface angles (0 degrees , 60 degrees , and 90 degrees ). Lower EMG values were obtained for the pliers with rubber grip and at 60 degrees of worksurface angle. EMG values varied significantly between the participants, but showed low correlations (Spearman's rank correlation = -0.27 approximately -0.58) with their work experience with the pliers. The hand discomfort and design satisfaction evaluations identified that the grip span (max = 14.0 cm) and grip force requirement (peak = 220.5 N) of the current pliers need ergonomic modification. The present study shows the needs of both the ergonomic design of a hand tool and the training of a proper work method to control work-related musculoskeletal disorders at the workplace.     

Occupational risk and prolonged standing work in apparel sales assistants

BackgroundThe prolonged standing posture during work affects the risk of developing musculoskeletal disorders of the lower limbs, especially in lack of alternative sitting. While different ergonomic tools are available to assess and manage the postural risk of the back and the upper limbs, there is a dearth of methods relative to the lower limbs.ObjectivesThe aim of this study is to assess the postural risk of sales assistants working in a prolonged standing posture, focusing on critical issues for the lower limbs.Methodsand criteria: 70 sales assistants employed among 9 apparel stores in northern Italy participated in the study. An observational approach was adopted, together with the application of standard ergonomic tools (Rula, Reba, Strain Index, Ocra) to assess the postural risk. Estimates of energy expenditure and movement's patterns were obtained through continuous monitoring with the Sense Wear Armband. Discomfort of the lower limbs was subjectively rated on the Borg's Cr-10 scale at the end of the work shift. The leg circumference was measured on each worker at intervals along the work shift.ResultsThe work of sales assistants in the apparel retail sector is characterized by the prolonged standing posture which accounts for more than 80% of the work shift duration; alternation with walking phases occurs according to assigned tasks and work organization.Activities of the upper limbs and occasional adopted awkward postures are observed, with the postural indexes varying between medium-high level of risk. The average distance walked during the work shift is 3,4 km. The musculoskeletal discomfort of the lower limbs reaches a medium-high intensity (CR 4–5) in 75% of the workers at the end of the work shift. Small but significant variations in the leg circumference were detected between beginning-end of the work shift (increase) and between beginning-end of the break interval (decrease).ConclusionOur data suggest that an indefinite level of risk of developing discomfort and musculoskeletal disorders of the lower limbs is real in sales assistants who work in a prolonged standing posture. The lack of specific assessment tool and of preventive measures could aggravate the exposure level.     

Musculoskeletal symptoms among commercial fishers in North Carolina

Musculoskeletal symptoms were reported by 215 fishermen followed at 6-month intervals over 18 months. Exposure information was collected through field observation and in-depth ethnographic interviews allowing potential ergonomic stressors to be identified and catalogued by task and stage of work. Symptoms causing work interference in the last 12 months were reported by 38.5% of the cohort at baseline. Low back symptoms were the most common cause of work impairment (17.7%), followed equally by pain in the hands or wrists and shoulders (7%). Symptoms in any body region were more likely to have been reported among individuals who did not fish full-time and those who worked other jobs part or all year had significantly lower symptom prevalence; both likely reflect a healthy worker effect. A number of ergonomic stressors were identified in all stages of fishing with exposure variability dictated by some unpredictable factors such as weather; but also by type of boat, gear, crew size, and level of experience. Reducing ergonomic exposures associated with work among these traditional workers is important, regardless of whether they directly cause or contribute to their musculoskeletal symptoms, or aggravate existing pathology.     

Ergonomic on-the-job training of assembly workers. Arm-neck-shoulder complaints drastically reduced amongst beginners

Assembly workers at a chain saw factory in Sweden were ergonomically instructed with the purpose of adjusting their movement patterns so that the muscular load on their upper extremities was kept below the critical level, defined as 10% of the maximum voluntary contraction. The study included two separate categories of subjects: new workers without previous experience of assembly work, and workers with at least one year's experience. As a result of the ergonomic instruction, the number of days lost through arm-neck-shoulder complaints was reduced by half in the test group consisting of new workers, compared with the corresponding control group with no ergonomic training. Amongst the experienced workers, however, the difference between the test group and the control group was statistically non-significant. The study showed that ergonomic monitoring and training are necessary to benefit fully from improved workplaces and tools. Considering the results accomplished amongst the new workers and given the extent of sick leave for the upper extremities, it seems that ergonomic interventions to prevent arm-neck-shoulder complaints at an early stage are extremely worthwhile.     

Prediction of work-related musculoskeletal discomfort in the meat processing industry using statistical models

Musculoskeletal disorders are one of the most common occupational disorders in the manufacturing industry, and cause pain, suffering, disability and a decrease in productivity. The objective of this study was the development of statistical models for the prediction of work-related musculoskeletal discomfort. A sample of 174 workers of the meat processing industry was taken. Diverse ergonomic evaluation methods were applied on data collected by means of direct observation and surveys. Later, pattern recognition techniques were used to identify the relevant predictor variables from an initial set of 20 variables. A prevalence of musculoskeletal discomfort of 77% was found. The most suitable classification models to predict the discomfort were the models based on logistic regression and decision trees. Statistical models were obtained to predict discomfort in shoulders, back, hands/wrists and neck with a precision between 83.3% and 90.2%. The findings can be useful to guide improvement initiatives according to the specific characteristics of the job and the profile of the worker.     

Construction of an osteomuscular discomfort scale for the upper region of the body of footwear industry workers

The objective of this study was to build a scale of musculoskeletal discomfort for the upper body of footwear industry workers. The self-reported symptoms of 1821 workers were analyzed via exploratory factor analysis and item response theory. The anatomical regions located in the upper body showed ability to discriminate workers with different levels of musculoskeletal discomfort. A scale with six levels was built, ranging from minimal discomfort to maximum discomfort, with greater precision of discomfort scores between 0 and 3. The region of least discomfort on the scale only indicates rare symptoms in the left shoulder. In the region of maximum discomfort, workers experience symptoms in all regions analyzed on a daily basis, with emphasis on the elbows, neck, trapezius, and middle and upper back. The scale has satisfactory psychometric properties to assess musculoskeletal symptoms in footwear industry workers and can be useful in ergonomic studies.     

Annual incidence of non-specific low back pain as an occupational disease attributed to whole-body vibration according to the National Dutch Register 2005–2012

Non-specific low back pain (nLBP) is the second most important reason for sick leave in the Netherlands, and more than 50% of the workers on sick leave attribute these complaints to their work. To stimulate recognition and prevention, an occupational disease (OD) registration-guideline was implemented for the assessment of the work-relatedness of nLBP in the Netherlands in 2005. The aim of this study is to present the annual incidence of nLBP as an OD and specifically for whole-body vibration (WBV) including patient characteristics such as age, sick leave and actions initiated by the occupational physician (OP). The data were retrieved from the National Dutch Register for 2005–2012. Each year about 118 OPs reported 509 cases (SD 139) of nLBP as an OD in a Dutch working population of 7.5 million workers (8% of all annual reported ODs). Less than 1% of these cases were attributed to WBV: 94% were men, 45% were between 51 and 60 years and 35% were on sick leave for more than 2 weeks. Most initiated actions were ergonomic interventions (35%).     

Design of assembly lines with the concurrent consideration of productivity and upper extremity musculoskeletal disorders using linear models

Work-related musculoskeletal disorders (WMSDs) are common occupational diseases among assembly workers due to repetitive motions or heavy workloads. The conventional approaches to decreasing WMSDs in assembly workers usually focus on individual assembly work at the station level. These approaches, however, do not pay enough attention to work allocation at the whole assembly line level such as balancing ergonomic burdens among workers by proper work assignment. This paper presents a methodology that can be used to integrate ergonomic measures of upper extremities into assembly line design problems. Linear models are developed to link work-worker assignment to the upper extremity ergonomic measures based on a guideline from American Conference of Governmental Industrial Hygienists. These linear models allow ergonomic and productivity measures to be integrated as a mixed-integer programming model. The case studies of this paper show the new model can effectively balance and control exposure levels in the upper extremity while not significantly decreasing line efficiency. This research shows the potential to reduce the need of numerous task adjustments for ergonomic improvement after initial assembly line design in conventional trial-and-error based assembly task adjustment. Furthermore, these linearization methods can be generalized in order to incorporate other ergonomic measures in tabulated forms into assembly line design problems.     

Prevention of musculoskeletal disorders at work: Validation and reliability in a multicenter intervention study

During the years 1986–1989 The Finnish Work Environment Fund initiated a multicenter, intervention study (programme) to prevent musculoskeletal disorders at work. The programme consisted of four different projects comprising methodological, epidemiological, and interventive themes. The main results were as follows: (1) More than half of the occupational physiotherapists and physicians involved in the project felt that they did not have adequate training for testing the performance capacity of the musculoskeletal system. Several of the most commonly used musculoskeletal tests had either poor validity in predicting future musculoskeletal troubles or had poor reliability. (2) A controlled intervention study showed that active training of neck-shoulder muscles can prevent musculoskeletal troubles, even more than ergonomic actions. (3) It is possible to reduce sick-leave due to low-back disorders by intervention measures directed toward both the work (environment, tools) and the workers (working methods, positive attitude to work, preparedness to keep fit). (4) The identification of ergonomic hazards with the help of teamwork proved to be feasible. The practical improvements, however, were difficult to implement in the prevailing conditions. Some of the improvements increased the work load and the stress of the workers. This aspect needs further consideration.     

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

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

Ergonomic,job task,and psychosocial risk factors for work‐related musculoskeletal disorders among teleservice center representatives

A cross‐sectional study was conducted to evaluate the association between work‐related musculoskeletal disorders (WRMDs) and work conditions, perceived exhaustion, job dissatisfaction, and job‐stress issues at two teleservice centers (TSCs). The study covered teleservice representatives who respond to toll‐free calls for assistance. The work involves a computer or manual search for information, and data entry using keyboards. One facility had upgraded the furniture at the workstations; the other facility had not. A questionnaire survey among 114 teleservice representatives and an ergonomic evaluation were conducted to determine WRMDs and their risk factors and perceived job stress. A high prevalence of symptoms of WRMDs was found at both TSCs. Suboptimal ergonomic conditions were associated with neck, shoulder, elbow, and back WRMDs, as well as with increased job dissatisfaction. Perceived increased workload variability and lack of job control were associated with the occurrence of neck and back WRMDs, respectively. WRMDs were more frequently reported by teleservice representatives at the center with older furniture and suboptimal ergonomic conditions. WRMDs may be prevented by improving ergonomic conditions at workstations and addressing work‐organization elements.     

Task design, psycho-social work climate and upper extremity pain disorders--effects of an organisational redesign on manual repetitive assembly jobs.

A company redesign was carried out to improve production efficiency and minimise the prevalence of work-related musculoskeletal disorders and sick leave. The redesign was evaluated on the basis of studies of assembly workers before (17 workers) and after (12 workers) the redesign. The redesign resulted in more varied, less repetitive, and more autonomous assembly jobs. The psycho-social work climate was both improved and impaired. A medical examination showed that eight of 17 workers before and nine of 12 workers after the redesign suffered from upper extremity pain disorders. Neither the production goals nor the goals of the redesign were fulfilled. Our conclusion was that the increased task variation and impaired psycho-social work climate, combined with a lack of skill and competence, actually increased the physical stress, risk for disorders and difficulties in fulfilling the production goals.     

A preliminary assessment of physical work exposures among electronic waste workers at Agbogbloshie,Accra Ghana

Occupational exposure associated with unstructured, informal e-waste recycling has received very limited attention. This study aimed to quantify the occupational physical exposures among informal e-waste workers at the largest e-waste site in Africa.A cross-sectional field survey of 163 male e-waste workers was conducted using a self-report occupational physical activity questionnaire, along with direct work observations, and pedometer estimates of walking activity for a subset of workers (n = 42).Results indicated significant differences in self-reported 7-day work exposures among the three main e-waste job categories, namely, collectors (n = 70), dismantlers (n = 73) and burners (n = 20). Prolonged walking, sitting and standing on five or more days in the workweek was frequently reported by collectors (87%), dismantlers (82%) and burners (60%), respectively. Nearly 90% of collectors and burners and 60% of dismantlers reported lifting and carrying on five or more days in the workweek.The exposure combinations identified suggest a risk for musculoskeletal disorders (MSDs). Findings call attention to the need for research examining potential associations between physical exposures and MSDs affecting e-waste workers in Agbogbloshie. The high exposure variability both between and within workers has implications for future exposure assessments conducted in unregulated, informal work settings.     

Work posture, workstation design, and musculoskeletal discomfort in a VDT data entry task

Self-report data on musculoskeletal discomfort were collected from several hundred VDT users in two agencies of a state government. Aspects of worker posture and workstation design were objectively assessed for 40 of the VDT users. Multiple regression analyses were used to examine the relationship between these ergonomic variables and musculoskeletal discomfort. Effects of ergonomic factors on musculoskeletal discomfort were clearly evident in the analyses. Regression models explained up to 38% of the variance in discomfort at different body sites. Of special interest was that leg discomfort increased with low, soft seat pans, suggesting that postural constraint is more important than thigh compression as a risk factor for leg discomfort in VDT work. In addition, arm discomfort increased with increases in keyboard height above elbow level, supporting arguments for low placement of the keyboard. Finally, high levels of neck and shoulder girdle discomfort observed in the study population suggest the need for further attention to the control of cervicobrachial pain syndromes in VDT work.     

Prevalence of back pain and characteristics of the physical workload of community nurses

Abstract

A research project is described that analyses the back pain prevalence and physical working conditions of community nurses. The purpose was to compare the position of nurses working in institutional care with the specific situation of nurses working in the private homes of their patients. The results of a questionnaire showed that the back pain prevalence was relatively high as compared to other occupations and also when compared to other health care sectors. The home care organization is influenced not only by sick leave due to back pain, but also its efficiency is hampered by nurses with back pain who continue to work. It appeared that the total sick leave incidence due to musculoskeletal disorders other than back pain exceeds that due to back pain alone. The physical exposure level not only consisted of frequent and heavy lifting and transferring of patients but also a substantial static workload was present. The onset of back pain seems to result from a gradual build up of overload reaching its maximum. A preventive approach should take these differential loading factors into account. The consequences for preventive interventions are discussed resulting in recommendations towards a (participatory) ergonomic approach. This material forms the baseline of a controlled prospective trial in home care.     

Ergonomic risk factors in glass artware industries and prevalence of musculoskeletal disorder

Glass artware manufacturing activities are highly repetitive, labor-intensive, and demand prolonged standing during the working shift. This leads to the development of musculoskeletal disorders (MSDs) symptoms among the workers. However, there is a scarce of study on the prevalence of MSDs symptoms and their associated risk factors among the glass artware workers. To address this research gap, this study aims to evaluate the prevalence of MSDs and working conditions among Indian glass artware workers. Discomfort data is collected using Cornell Musculoskeletal Discomfort Questionnaire and working posture data is collected through direct observations using Rapid Entire Body Assessment (REBA). Multiple logistic regression model is developed for each body region to study the relationship between the associated risk factors and MSDs symptoms with the help of collected data. The findings of this study are first, MSDs symptoms are highly prevalent and severe, particularly in the lower back, thigh, and foot. Second, the average REBA grand score is 7.22, which reveals the high-risk level of worker's posture while performing the task. Third, Job characteristics and individual factors are associated with MSD symptoms in multiple logistic regression models. The results highlight the prevalence and severity level of MSDs and illustrate the demand for ergonomic interventions to alleviate musculoskeletal symptoms among these working groups.Relevance to industryThis study draws attention to work-related and other associated risk factors, which would help the researchers and managers to understand the working environment of glass artware industry. These risk factors should be considered for designing and implementing ergonomic interventions to prevent and alleviate musculoskeletal discomfort among the glass artware workers.