Musculoskeletal disorders in labor-intensive agriculture

This paper gives an overview of the extent of musculoskeletal disorders (MSDs) in agriculture, and a historical perspective on how ergonomics has been used to reduce the health effects of labor-intensive agriculture. A summary of exposure to MSD physical risk factors within various classes of crops, along with various administrative and engineering controls for abating MSDs in agriculture is given. These controls range from programmed rest breaks to mechanized or partially-mechanized operations. Worker-based approaches such as prone carts and platforms, and load transfer devices hold promise in combating the prevalent stooped work in agriculture. Including the worker as an integral contributor to all aspects of developing and implementing an intervention, and considering the psychosocial and socio-cultural aspects of the work environment are crucial elements of effective interventions for reducing MSDs. Despite the advent progress in new technologies in agricultural practices, reliance on labor, especially in fresh market fruits and vegetables, will always be a major cornerstone of agriculture for at least the foreseen future. It is encouraging to see the increased interest among health and safety professionals, epidemiologists, engineers, social scientists, and ergonomists throughout the world who are committed to the plight of reducing MSDs and other health problems among agricultural workers.     

Musculoskeletal disorders assessment using sick-leaves registers in a manufacturing plant in Spain

The incidence rates of sick-leave caused by musculoskeletal disorders (MSDs) were registered in 2013 in a Spanish manufacturing plant of electrical appliances applying a detailed analysis to the sick-leave data using Poisson regression considering the gender, age and working area.The adjusted incidence rates estimated using Poisson regression show a higher incidence for workers over age 50, and a higher incidence of neck-related MSDs sick-leave for working area of presses and veneers. As for back injuries, workers over age 50 and of assembly induction working area present the highest risk of sick-leave.Relevance for the industryThe results obtained in this study could be a reference to manufacturing plants of electrical appliances or similar to design MSDs' prevention policies, with the aim of reducing sick leaves and its associated costs. This information allows us to detect the working areas with higher incidence, more susceptible subjects as well as more sensitive areas of the body in order to target interventions towards those.     

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.     

Musculoskeletal disorders as a fatigue failure process: evidence,implications and research needs

Abstract

Mounting evidence suggests that musculoskeletal disorders (MSDs) may be the result of a fatigue failure process in musculoskeletal tissues. Evaluations of MSD risk in epidemiological studies and current MSD risk assessment tools, however, have not yet incorporated important principles of fatigue failure analysis in their appraisals of MSD risk. This article examines the evidence suggesting that fatigue failure may play an important role in the aetiology of MSDs, assesses important implications with respect to MSD risk assessment and discusses research needs that may be required to advance the scientific community’s ability to more effectively prevent the development of MSDs.

Practitioner Summary: Evidence suggests that musculoskeletal disorders (MSDs) may result from a fatigue failure process. This article proposes a unifying framework that aims to explain why exposure to physical risk factors contributes to the development of work-related MSDs. Implications of that framework are discussed.     

Musculoskeletal outcomes in multiple body regions and work effects among nurses: the effects of stressful and stimulating working conditions

This study investigated the various stressors encountered by the nursing profession. In particular, the following hypotheses were tested: (1) working conditions of nurses significantly affect perceived risk of injury and illness, work dissatisfaction, work satisfaction, energy state at the end of workday, the effort exerted by the registered nurse (RN), psychosomatic outcomes, and musculoskeletal symptoms (in multiple body regions); (2) both intermediate work effects (i.e., effort, perceived risk of injury/illness, work satisfaction/dissatisfaction, energy state at end of workday) and psychosomatic outcomes significantly affect musculoskeletal outcomes (in multiple body regions); (3) both working conditions and effects significantly affect musculoskeletal outcomes. In a preliminary study conducted on 34 registered nurses, results show that: (1) stressful working conditions affect musculoskeletal outcomes in multiple body regions, and (2) physical maladies such as lower back problems are not only associated with physical factors but also with a complex interaction of working conditions. Further research is warranted to obtain a better understanding of the complex interaction and the synergistic effects of the various nursing working conditions.     

A cross-sectional study of self-reported back and neck pain among English schoolchildren and associated physical and psychological risk factors

This study set out to identify the associations between ergonomics and other factors with back and neck pain among schoolchildren. Self-reported questionnaires were used to record health outcomes and potential risk factors in state schools. Six hundred and seventy-nine schoolchildren from Surrey in the United Kingdom aged 11–14 years took part. Twenty-seven percent of children reported having neck pain, 18% reported having upper back pain, and 22% reported having low back pain. A forward stepwise logistic regression was performed with pain categories the dependent variables. Neck pain was significantly associated with school furniture features, emotional and conduct problems, family history of low back pain and previous treatment for musculoskeletal disorders. Upper back pain was associated with school bag weight (3.4–4.45 kg), school furniture features, emotional problems and previous treatment for musculoskeletal disorders. Low back pain was associated with school furniture features, emotional problems, family history and previous injury or accident. It is important to recognise the influence of physical, psychological and family factors in children's pain.     

Evaluation of an intervention comprising a no lifting policy in Australian hospitals

The No Lifting Policy has been adopted in Australia to prevent back pain and injuries among nurses. The present study focuses on the intervention of the "No Lift System" (NLS). The purpose of this cross-sectional study was to evaluate the use of transfer equipment, number of injuries, pain/symptoms and absence from work among nurses after the intervention of the NLS (n=201), and compare to nurses at two control hospitals (n=256). A comprehensive questionnaire was used for data collection. The results show that at the hospital where the NLS had been introduced, the nurses used the purchased transfer equipment regularly. They had significantly fewer back injuries, less pain/symptoms and less absence from work due to musculoskeletal pain/symptoms compared with nurses at the control hospitals. The study showed strong evidence for supporting the implementation of the NLS. The positive results shown in the present study can probably be explained by the agreement between the management, the union and the nurses concerning the implementation of the NLS, as well as its comprehensive approach and participatory design.     

The role of whole-body vibration in back pain: A cross-sectional study with agricultural pilots

ObjectiveA cross-sectional study was conducted to investigate the role of whole-body vibration as a risk factor for spinal musculoskeletal symptoms among agricultural pilots.MethodThe study was conducted in two stages that included measuring the pilots’ exposure to whole-body vibration during the flight procedures and applying a self-administered questionnaire about musculoskeletal symptoms of the spine.ResultsNone of the four aircraft texted exposed the pilot above the Exposure Limit Value (ELV) established by the standards. However, in a few specific situations, two of them exceeded the Exposure Action Value (EAV). About 62% of the pilots who operated these aircraft reported some musculoskeletal symptoms of the spine in the last few 12 months.ConclusionUsing the data from this study, it was possible to calculate the odds ratio of the agricultural pilot suffering low back pain, based on eight personal and work-related factors.Relevance for the industryBased on the results of the present study, it was possible to define strategies to reduce whole-body exposure in agricultural aircraft and, consequently, improve the pilots’ health. Strategies included management of the exposure and aircraft improvement.     

Musculoskeletal disorders among visual display terminal workers: individual,ergonomic, and work organizational factors

A number of individual, ergonomic, and organizational factors of presumed importance for the occurrence of musculoskeletal disorders were investigated in a group of 260 visual display terminal (VDT) workers. The cross-sectional study utilized medical and workplace investigations as well as questionnaires. The results were subjected to a multivariate analysis in order to find the major factors associated with various upper-body muscular problems. Several such factors were identified for each investigated type of musculoskeletal problem. Some were related to the individual: age, gender, woman with children at home, use of spectacles, smoking, stomach-related stress reactions, and negative affectivity. Organizational variables of importance were opportunities for flexible rest breaks, extreme peer contacts, task flexibility, and overtime. Identified ergonomic variables were static work posture, hand position, use of lower arm support, repeated work movements, and keyboard or VDT vertical position.     

Work-related musculoskeletal disorders in home care nurses: Study of the main risk factors

BackgroundNurses are a risk group for work-related musculoskeletal disorders (WMSDs). Several studies reveal that nurses have high prevalence rates of injuries and symptoms related to WMSDs. However, many of these studies focus mostly on hospital nurses. Worldwide, few studies include home care nurses.ObjectiveThis work aimed to identify the body region most affected by musculoskeletal complaints in home care nursing, and subsequently develop a statistical model, that includes the main risk factors, to predict the risk of having musculoskeletal complaints in the identified region.MethodsThe research method was based on the Standardised Nordic Questionnaire applied to home care nurses working at Health Centres of northern Portugal. Univariate and multivariate models of logistic regression were used to meet the goals of this work.ResultsHome care nurses have a three times greater chance of having lumbar complaints than their counterparts working only at Health Centres (OR = 3.19 (p < 0.05), with a 95% confidence interval [1.256; 8.076]). A statistical model with seven variables (forearm posture; static postures; arm posture; arm supported; bed height; job satisfaction; assistive devices) was obtained to predict lumbar complaints.ConclusionsThe lumbar region was identified as the most affected by musculoskeletal complaints. These complaints were associated with seven factors.     

Prevalence of musculoskeletal symptoms in relation to gender, age, and occupational/industrial group

Although musculoskeletal symptoms (MSS) are common worldwide, little is known about its prevalence amongst the working population in relation to gender, age, and occupational/industrial group. This paper describes the prevalence of MSS in a sample of 3003 men and women aged 20-64 randomly selected from the New Zealand Electoral Roll. MSS experienced during the previous 12 months in 10 body regions was assessed in telephone interviews using a modified version of the Nordic Musculoskeletal Questionnaire (NMQ). MSS prevalence was 92% (for any body region). The highest prevalence was for low back (54%), neck (43%), and shoulders (42%). Females reported a statistically significantly higher prevalence of MSS in the neck, shoulders, wrist/hands, upper back and hips/thighs/buttocks regions compared to males while males reported more symptoms of the elbows, low back and knees. There were no statistically significant differences in prevalence among age groups. In general, participants with heavy physical workloads had significantly higher prevalence of symptoms in most body regions than those with light physical workloads although women with light physical workloads reported more neck symptoms. The study indicates that the New Zealand working population has a high prevalence of MSS and that exposure in the workplace plays a role.

Relevance to industry

The findings of this study imply that efforts to reduce MSS in the workplace should focus on females and employees with high physical workloads.     

A test of two training interventions to prevent work-related musculoskeletal disorders of the upper extremity

We investigated, on behalf of a large electronics manufacturer, two types of worker training interventions for their efficacy in preventing unnecessary muscle tension and the symptoms of work-related musculoskeletal disorders. The first intervention, Muscle Learning Therapy (MLT), used electromyographic (sEMG) feedback and operant conditioning to decrease muscle tension during complex work tasks. The second intervention used adult learning and cognitive behavioral techniques in small group discussion to advance the worker's capabilities for symptom and stress management and problem-solving. Workers were randomly assigned to a control group or one of the two treatment conditions. Prior to training, baseline data were collected using symptom diaries and sEMG recordings of the trapezius and forearm muscles of the left and right arms. The training interventions were conducted for 6 weeks with reinforcement training provided at 18 and 32 weeks post-baseline. Follow-up data were collected after the initial 6-week training period and at 32 weeks, prior to the reinforcement training. Symptom outcomes demonstrated significant differences at 6 weeks, increasing in severity for the control group and declining modestly for the educational group, with little change for the MLT group. These differences were not maintained at further follow-up. The MLT group was consistently effective in reducing muscle tension in the trapezius areas after 6 and 32 weeks, and was partially effective for the forearms. Further testing is recommended of these training interventions, especially with the inclusion of strategic, periodic reinforcement of the worker's learning.     

The Suitability for the Work‐Related Musculoskeletal Disorders Checklist Assessment in the Semiconductor Industry: A Case Study

Musculoskeletal disorders and symptoms are common among workers in the semiconductor and related industries. Ergonomic‐related checklists are used to identify musculoskeletal disorder risk factors in the workplace. This study explores the suitability of the Occupational Safety and Health Administration (OSHA) musculoskeletal disorders (MSDs) checklist for use in the semiconductor manufacturing industry. Six companies were enrolled in the current study, and 122 subjects, ranging in age from 21 to 54 years old, were evaluated through a questionnaire survey and field observation using the OSHA MSDs checklist. The observers were administered an ergonomics‐based checklist training course with a duration of 36 hours. Experimental results demonstrated that nearly 50% of subjects reported physical discomfort, with shoulder symptoms (38.5%) being the most common complaint. In addition, the aggregated sensitivity, specificity, and positive predictive values for the MSDs checklist in the six companies were 47.3%, 62.4%, and 30.0%, respectively. This study concluded that the OSHA MSDs checklist appeared to contain better estimates for capturing musculoskeletal discomfort and found that the OSHA MSDs checklist provided an easily administered, proactive surveillance instrument to assist in early identification of musculoskeletal discomfort. © 2012 Wiley Periodicals, Inc.     

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.     

A randomized and controlled trial of a participative ergonomics intervention to reduce injuries associated with manual tasks: physical risk and legislative compliance

A participative ergonomics approach to reducing injuries associated with manual tasks is widely promoted; however only limited evidence from uncontrolled trials has been available to support the efficacy of such an approach. This paper reports on a randomized and controlled trial of PErforM, a participative ergonomics intervention designed to reduce the risks of injury associated with manual tasks. One hundred and seventeen small to medium sized food, construction, and health workplaces were audited by government inspectors using a manual tasks risk assessment tool (ManTRA). Forty-eight volunteer workplaces were then randomly assigned to Experimental and Control groups with the Experimental group receiving the PErforM program. Inspectors audited the workplaces again, 9 months following the intervention. The results showed a significant decrease in estimates of manual task risk and suggested better legal compliance in the Experimental group.     

Processes, barriers, and outcomes described by ergonomics consultants in preventing work-related musculoskeletal disorders

Despite the importance of reducing work-related musculoskeletal disorders, there appears to have been little evaluation of routine ergonomics consultancy interventions aimed at reducing risks leading to these conditions. In many instances, the effectiveness of advice depends on organisations accepting and implementing measures recommended, involving changes of both individual and collective behaviour. Behaviour change theory, developed elsewhere, suggests that if change is to take place, recipients need to hold positive attitudes and beliefs relating to the desirable behaviour. To investigate the extent to which this is accommodated by current ergonomics consultancy practices, 14 ergonomics consultants were interviewed to explore the consultancy process from which recommendations are developed, exploring the factors that are assessed by consultants, perceived barriers to promoting change, and the extent to which evaluation of outcomes takes place. Consultants' recommendations generally focused on physical aspects of the work environment and did not take explicit account of employees' knowledge or attitudes. Little evaluation of outcomes was conducted by the consultants interviewed. Implications of these findings for improving the efficacy of interventions to reduce work-related musculoskeletal disorders within organisations are discussed.     

Computer-telephone interactive tasks: predictors of musculoskeletal disorders according to work analysis and workers' perception

Sixty-two workers engaged in computer-telephone interactive tasks in an active telemarketing center and a telephone call center of an international bank subsidiary in S?o Paulo. Brazil, were assessed by means of a work analysis and a self-administered questionnaire aiming to determine the statistical relationship of ergonomic, organizational and psychosocial characteristics of their jobs with the report of symptoms in neck-shoulder and hand-wrist for more than 7 consecutive days and any time away from work during the current job due to musculoskeletal disorders (MSD). According to chi-square univariate tests and multiple logistic regression models, active telemarketing operations, duration in the job and the low level of satisfaction with the physical arrangement of the workstation emerged as the factors most related to neck-shoulder and hand-wrist MSD and MSD-induced time away from work. This study emphasizes the role of psychosocial factors and duration in the job in MSD occurrence and induced absenteeism among workers engaged in computer-telephone interactive tasks.     

Self-administered questionnaire and direct observation by checklist: comparing two methods for physical exposure surveillance in a highly repetitive tasks plant

Background

We evaluated the agreement between a questionnaire and an observational checklist for exposure assessment in the setting of an upper-limb work-related musculoskeletal disorders (UWMSD) surveillance program in a population with a high level of physical exposures.

Methods

A surveillance program was implemented in a large shoe factory. Physical exposures were assessed in 1996 by a self-administered questionnaire and by the direct observation of work tasks assessed using a checklist filled out by trained assessors. Items were summed into a “questionnaire” score and an “observational” score. These scores were compared by Pearson's correlation. The association between exposure assessment by each method and UWMSD incidence between 1996 and 1997, defined by a standardized examination, was also studied.

Results

Correlation between the “questionnaire” score and the “observational” score was low among the 196 workers (77%) who received both evaluations (rho=0.06, p>0.05). Only exposure assessed by the questionnaire method was significantly associated with high incidence of UWMSD between 1996 and 1997, with good sensitivity (97%) and poor specificity (27%).

Conclusion

In this surveillance program, self-reported physical exposures assessed by questionnaire and by direct observation did not evaluate same dimensions of high physical exposures. In this sample, exposures assessed by questionnaire identified workers at high risk of incident UWMSD more precisely than exposures identified by direct observation.     

The future of research in understanding and controlling work-related low back disorders

Our knowledge of low back disorder (LBD) causation has progressed well over the years with in-depth understanding accelerating in the traditional disciplines of biomechanics, psychology, psychophysics, psychosocial, physiology, genetics, organizational psychology and rehabilitation. However, each of these disciplines has studied LBD causality in isolation of other disciplines. The underlying assumption is that each discipline can fully explain causality and each discipline is treated as if it were mutually exclusive and exhaustive of the other disciplines. Hence, the body of knowledge has progressed along research silos where we have in-depth knowledge along given research tracks that are defined by the boundaries of the discipline. Furthermore, a wealth of knowledge has been amassed within each of these research silos. How can they all be correct if they are indeed mutually exclusive and exhaustive? The answer is: they cannot be. This brief review of the state-of-the art in LBD research applied to ergonomics, suggests that instead of observing LBD through the myopic lens of each discipline, we need to begin to view LBD causality as a system. Recent work attempting to understand the interaction between these traditional disciplines has demonstrated that many of the findings along these silos are really interrelated and can be explained in terms of changes in the biomechanical loading at the tissue level. It is argued that further efforts to understand these interactions represent the next level of understanding causality of LBDs.     

The investigation of work-related musculoskeletal disorders among female workers in a hazelnut factory: Prevalence,working posture,work-related and psychosocial factors

BackgroundWork-related musculoskeletal disorders (WMSDs) are the most common occupational health problems in the industrialized world. The identification of WMSDs specific to occupation is essential to plan and implement preventative programs. This study investigated the prevalence of WMSDs and determined the factors related to the severity of the most common disorders among female workers in a hazelnut factory.MethodsA total of 114 female workers were examined in this cross-sectional study using the Nordic Musculoskeletal Questionnaire, the Dutch Musculoskeletal Questionnaire, and an author-developed questionnaire (for socio-demographic characteristics and psychosocial factors). Working posture, craniovertebral angle, thoracic kyphosis angle (TKA), and lumbar lordosis angle were evaluated based on a photogrammetry method using the ImageJ program.ResultsThe prevalence of WMSDs in at least one body part during the last 12 months was 92.1%. The highest prevalence of WMSDs was in the lower back (61.4%), neck (57.9%), shoulder (53.6%), and upper back (45.6%). The least affected part was the elbow. Lower back, shoulder, and neck disorders were the most common causes of activity limitation. The severity of lower back pain was associated with stress in the workplace and work-related factors. The neck pain severity was related to craniovertebral angle and work-related factors. The shoulder pain severity increased with TKA and employment duration. TKA was related to upper back pain severity.ConclusionsWMSDs are common among female workers in a hazelnut factory. Reorganizing of working posture, work-related factors, and stress at work may be beneficial to decrease the prevalence of WMSDs and pain severity.Relevance to Industry; The female workers in the hazelnut factory are vulnerable to the work-related musculoskeletal disorders, particularly in the spinal region. The employers should endeavor to improve the health of the workers by the adjustment of the working posture and environmental factors.