• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.273-278
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• 2013

Objective: This study aims to analyze and evaluate fatigue in upper trapezius muscles of adults when inputting text on a smart phone, thereby examining the risk of cumulative trauma disorders in the musculoskeletal system of the upper extremity. Method: Forty-five healthy adults were divided equally into three groups: a smartphone group, a notebook group, and a desktop group. A surface electromyogram was placed on the upper trapezius muscle of each participant, after which they inputted text for ten minutes within an ergonomic setting; their side posture was recorded on video and analyzed. Results: The spectral edge frequency values for the smartphone group, as recorded from the upper right trapezius muscles on the surface electromyogram, showed a significant decrease(p<.05). Regarding the RULA, all three groups had results indicating "action level 2". Conclusion: All three groups had results indicating "action level 2" according to the RULA, which means that additional research on the posture of the participants while performing tasks is necessary, and their posture needs to be corrected. In particular, the smartphone group has the highest levels of fatigue in the upper trapezius muscles, suggesting that the task of inputting text on a smartphone is a high risk for causing cumulative trauma disorders.

• Journal of the Korea Safety Management & Science
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• v.10 no.4
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• pp.21-30
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• 2008

The psychosocial stress and musculoskeletal disorders(MSDs) have been one of major health problems for hospital workers. This study tried to understand the relationship between symptoms associated with MSDs and risk factors such as working posture, job stress, psychosocial stress and fatigue. A total number of 655 hospital workers participated in this study. Specifically, REBA was applied for evaluating working posture and a checklist prepared by KOSHA(Korean Occupational Safety and Health Agency) was used for symptom survey. A questionnaire from KOSHA was also used for collecting data associated with job stress, psychosocial stress and fatigue. All these data were formulated and modeled by path analysis which was one of major statistical tools in this study. Specifically, path analysis for the data we collected came up with several major findings. The risk scores from working posture based on REBA had indirect effects via fatigue factor(MFS) as well as direct effects on symptoms. The factors associated with job stress (KOSS) and psychosocial stress(PWI-SF) had significant effects on symptoms. Specifically, indirect effect of job stress factors via fatigue factors(MFS) had bigger than that of direct effect of job stress on symptom.

• Physical Therapy Korea
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• v.17 no.1
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• pp.53-61
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• 2010

This study investigated the relationships between Work-related musculoskeletal disorders (WMSDs), contributing factors, and the occupational stress of physical therapists. Self-reported questionnaires were given to 180 physical therapists in Gangwon Province. Variables examined included the prevalence of pain sites related to WMSDs; pain intensity; pain pattern; and job stress, which is thought to involve the physical environment; job demand; insufficient job control; interpersonal conflict; job insecurity; organizational system; reward system; and occupational culture. Among physical therapists, work-related musculoskeletal pain commonly affected the low back (30.1%), shoulder (29.3%), and wrist (12.2%). The sites of work-related musculoskeletal pain treated medically were the low back (22.8%), shoulder (19.8%), neck (12.7%), and wrist (12.1%). "Repeating the same work constantly" was suggested to be the major cause of the pain. The younger therapists were significantly more likely to feel high job stress due to the physical environment (p<.05), job demand (p<.05), and organizational system (p<.01). Women were more likely to feel greater job stress related to job demand, insufficient job control, the organization system, and job rewards. Men were more likely to feel greater job stress related to job insecurity. Weak positive relationships were observed between work-related musculoskeletal pain and job stress, which is thought to involve the physical environment; job demand; insufficient job control; interpersonal conflict; job insecurity; organizational system; reward system; and occupational culture. Physical therapists appear to be at higher risk of WMSDs because 80.1% of the physical therapists studied experienced work-related musculoskeletal pain. To reduce the risk, we need intervention strategies such as preventive education, ergonomically designed medical equipment, a psychosocial approach to work conditions, improved mechanical conditions related to therapeutic patterns, and an institutional infrastructure with sufficient personnel and scheduling.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.163-172
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• 2003

Background and Purpose. Physical therapists are at risk for work-related musculoskeletal disorders (WMSDs). Little understand the characteristics of work in physical therapist or the effort they take to prevent injury. The purpose of this study was to investigate the characteristics of work in physical therapist and the efforts for prevent injury Subjects. Standardized questionnaire was administered to 103 physical therapist in Pusan association. Methods. An questionnaire was given to each subject. Questions investigated the characteristics of work in physical therapist, efforts and caring of injury prevention. Chi-square Test used to assess the association of general characteristics with the characteristics of work in physical therapist. AVONA and T-test used to assess the association of efforts of prevent injury in independent variable Results. Physical therapist was reported a higher prevalence of WMSDs in most body areas. These attributes sometimes resulted in behaviors that contributed to the development of their WMSDs.

• Journal of the Korean Society of Safety
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• v.26 no.1
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• pp.49-57
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• 2011

A questionnaire study was carried out to understand the status of performing the risk assessment of work-related musculoskeletal disorders(WMDSs), which is the employers' legal responsibility when the employees are involved in doing tasks with risk factors. Employers or managers from 340 companies and the representative employees from 250 companies participated in the survey. According to the participated employers and employees, 35.0~46.2% of companies had performed the first risk assessment before the end of 2005. However, it is presumed that the real condition might not be as much as the result, because most companies were very reluctant to took part in the survey. It was found that the type of business and size of the company are the main factors affecting the performance of the risk assessment in terms of the performing ratio, method, and so on. The participants were positive in the thought that the assessment would be helpful in preventing msuculoskeletal disorders, while there was a little difference between the employers and employees in the thought that the assessment would be helpful in finding the injuries in the early stage. It was found that it is necessary to modify and improve the definition and criteria of the tasks to be examined in the assessment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.276-283
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• 2006

Work-related musculoskeletal disorders (WMSDs) were a major source of disability and lost work time after 'Foreign Currency Crisis(1998-2000)' in Korea. There is considerable evidence documenting the association between psychosocial risk factors and work disability due to WMSDs. But, there is not much in Korea. The present study aimed to explore the predictive association between the changed working conditions and WMSDs after 'Foreign Currency Crisis' in Korea. A study sample of 8,670 automobile assembly workers were recruited for this study. A structured-questionnaire was used to assess general characteristics, working conditions, and information concerning medical treatment of WMSDs. After adjustment for sociodemographic factors, increased overtime work(OR=1.22), daily work time(OR=1.20), work speed (OR=1.32), number of workers(OR=0.83), supervisory control(OR=1.39), physical load(OR=1.39), and mental load (OR=1.25) were all founded to be significantly associated with WMSDs. This study has shown the importance of changed working conditions in the occurrence of WMSDs. Therefore, it will be necessary to reduce WMSDs with controlling both physical and psychosocial factors.

• Bulletin of the Korean Institute for Industrial Safety
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• v.3 no.1
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• pp.11-17
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• 2003

In recent years, work-related musculoskeletal disorders (WMSDs) are one of major issues in occupational safety and health in Korea, since the number of injured workers has rapidly increased and the related regulation was amended to improve the work conditions. Main risk factors of WMSDs in Korean industries include manual handling of heavy weight loads, awkward postures, repetitive tasks, prolonged static muscle contraction, and so on. in this article, some ergonomics case studies for identifying the risk factors of WMSDs and far their prevention were introduced. They include a biomechanical analysis for the heavy-weight handling task in a machine-repair shop, physiological evaluation of backpack-carrying tasks in a beverage delivery job, and a set of psychophysical studies to evaluate static-postural load. These studies showed that there are several different ergonomic approaches to identifying and evaluating risk factors of WMSDs and to eliminating them or reducing their levels, and that it is important to select proper methods and apply them in improving the work conditions according to the characteristics of the task. In addition, it needs to develop practical and effective ergonomic tools to prevent WMSDs and to provide these tools to the safety managers in the field so that they can improve the tasks by themselves.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.728-735
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• 2022

Roofers get exposed to increased risk of knee musculoskeletal disorders (MSDs) at different phases of a sloped shingle installation task. As different phases are associated with different risk levels, this study explored the application of machine learning for automated classification of seven phases in a shingle installation task using knee kinematics and roof slope information. An optical motion capture system was used to collect knee kinematics data from nine subjects who mimicked shingle installation on a slope-adjustable wooden platform. Four features were used in building a phase classification model. They were three knee joint rotation angles (i.e., flexion, abduction-adduction, and internal-external rotation) of the subjects, and the roof slope at which they operated. Three ensemble machine learning algorithms (i.e., random forests, decision trees, and k-nearest neighbors) were used for training and prediction. The simulations indicate that the k-nearest neighbor classifier provided the best performance, with an overall accuracy of 92.62%, demonstrating the considerable potential of machine learning methods in detecting shingle installation phases from workers knee joint rotation and roof slope information. This knowledge, with further investigation, may facilitate knee MSD risk identification among roofers and intervention development.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.95-101
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• 2013

This study tried to develop a basis for quantitative index of working postures associated with WMSDs(Work-related Musculoskeletal Disorders) that could overcome realistic restriction during application of typical checklists for WMSDs evaluation. The baseline data for this study was obtained from automobile manufacturing company(A total of 603 jobs were observed). Specifically, data for shoulder postures was analyzed to have a better and more objective method in terms of job relevance than typical methods such as OWAS, RULA, and REBA. Major statistical tools were Clustering, Logistic regression and so on. The main results in this study could be summarized as follows; 1) The relationships between working postures and WMSDs symptoms at shoulder were statistically significant based on the results from logistic regression. 2) Based on clustering analysis, three levels for WMSDs risk at shoulder were produced for both flexion and abduction were statistically significant. Specific results were as follows; Shoulder flexion: low risk(< $37.7^{\circ}$), medium risk($37.7^{\circ}{\sim}70.0^{\circ}$), high risk(> $70.0^{\circ}$) Shoulder abduction: low risk(< $26.5^{\circ}$), medium risk($26.5^{\circ}{\sim}56.8^{\circ}$), high risk(> $56.8^{\circ}$). 3) The sensitivities on risk levels of shoulder flexion and abduction were 64.0% and 20.6% respectively while the specificities on risk levels of shoulder flexion and abduction were 99.1% and 99.3% respectively. The results showed that the data associated with shoulder postures in this study could provide a good basis for job evaluation of WMSDs at shoulder. Specifically, this evaluation methodology was different from the methods usually used at WMSDs study since it tried to be based on direct job relevance from real working situation. Further evaluation for other body parts as well as shoulder would provide more stability and reliability in WMSDs evaluation study.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.307-314
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• 2013

Objectives: The aim of this study was to determine the prevalence of symptoms relating to musculoskeletal disorders (MSDs) and investigate the risk factors among researchers at university laboratories. Methods: 209 researchers were included in this study, drawn from 27 laboratories at three universities in Korea. Checklists for MSD symptoms and risk factor assessment were utilized. Results: The symptoms checklist showed reliable results with Cohen's Kappa 0.33-0.56, percent agreement 81.0-96.8%, and correlation coefficient 0.41-0.63. The overall prevalence of MSD symptoms was 68.9%, while the prevalence in specific parts of body were as follows: shoulders (47.6%), lower back (46.9%), neck (46.9%), knees (25.4%), wrists (20.1%), elbows (13.6%). The symptom prevalence among women was higher than among men (OR 2.67, 95% CI 1.37-5.18). Daily exposure time was observed to be a significant risk factor for developing MSD symptoms (OR 2.14-6.07). Conclusions: This study suggested that repetitive pipetting and static work posture are the most significant risk factors for MSD symptoms among laboratory researchers.