• IE interfaces
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• v.16 no.2
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• pp.222-228
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• 2003

Computer-dominated jobs and industrial automation have rapidly created work-related musculoskeletal disorders(WMSDs) and WMSDs are also founded in employees of other general industries. WMSDs has been growing problems for Korean industries with higher incidence rate every year. The objective of this paper is to analyze the effects of the neck muscle workload according to postures(joint angle) and load weights. Seven male students participated in this study. Neck workload was rated on each person using a Borg's CR-10 scale. ANOVA showed that the CR-10 ratings were statistically significant according to postures and load weights. To reduce the large number and severity of WMSDs, which employees have been experiencing, we need to redesign the job in workplace so that we can control hazards that are reasonably likely to be causing or contributing to the WMSDs. The results of this study can be used to establish the safety criteria of joint angle and weight of neck workload.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.148-153
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• 2005

Computer dominated jobs and industrial automation have rapidly created work-related musculoskeletal disorders(WMSDs) and WMSDS are expanding to employee of other general industry. Specific risk factors associated with WMSDs include repetitive motion, heavy lifting, forceful exertion, contact stress, vibration awkward posture and rapid hand and wrist movement. The purpose of this paper is to analyze the effects of the neck muscle workload according to posture(joint angle) and load weight. Seven male students participated in this study. To analyze neck muscle workload was studied on electromyographic(EMG) activity for sternocleidomastoid and trapezius, was subjectively rated using a Borg's CR-10 scale. ANOVA showed that the CR-10 ratings and most EMG root-mean-square (RMS) value were statistically significant improvement according to posture(joint angle) and load weight. The results of this study indicate the joint angle and weight of neck muscle workload to provide safe working conditions. To reduce the large number and severity of WMSDs employees have been experiencing, we need to redesign the job in workplace to identify and control hazards that are reasonably likely to be causing or contributing to the WMSDs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.69
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• pp.51-64
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• 2001

A laboratory experiment was conducted to investigate the effects of working posture. work/rest ration, and task type on the physical workload in automobile assembly jobs. Ten healthy male university students participated as subjects in the experiment. East subject performed 18 experimental session with combination of 3 working posture 3 work/rest ratio and 2 task types. To examine the effect of various working conditions on workload, DMG analysis was performed on 4 different muscles in the neck an arm area, Also RPE scale and heart rate were taken as response variables. The result showed that all working conditions considered in the experiment had significant effects on the workload concluding that labor intensity in auto assembly jobs should be adjusted with respect to different levels of working posture, work/rest ratio, and task type. Detailed analysis are presented in the paper.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.137-147
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• 2007

Dentists are known to be highly exposed to the musculoskeletal disorders (MSD). The present study investigated the prevalence of MSD among Korean dentists and association between their MSD and physical workload. In addition, work-related causes of high physical workload were identified and needs of dentists were collected for improvement of dental instrument and environment. Four types of questionnaires including the Nordic questionnaire were used to investigate body troubles, physical workload, causes of physical workload, and improvement priority of dental components. A total of 104 dentists in Seoul were participated in the survey. Neck trouble (82%) was the most prevalent in the participated dentists and shoulder (68%) and low back trouble (56%) followed, while low back trouble was reported to be most common in previous western studies. The body troubles were related to the physical workload of the corresponding body parts, although they were not associated with personal characteristics. Most dentists selected 'to keep direct view inside patient's mouth' and 'no support of the hand with dental instruments' as causes of awkward and strenuous work postures. They wanted design improvement for some components in their operating room such as operating light and arrangement of workplace.

• Safety and Health at Work
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• v.9 no.3
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• pp.326-333
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• 2018

Background: Echocardiography involves strenuous postures of the upper limbs. This study explored the physical workload in the neck and upper limbs in sonographers performing echocardiography, and the extent to which the workload differs from than in other work tasks (other sonographic examinations, and nonsonographic tasks). Methods: The physical load was assessed by inclinometry, goniometry, and electromyography methods in 33 female sonographers during authentic work using three different echocardiography techniques and other work tasks. Results: Echocardiography was characterized by low velocities of the head, arms, and wrists, and a low proportion of muscular resting time in the forearms, in the transducer limb, and the computer limb. The transducer limb was more elevated in one of the techniques, but this technique also involved a higher proportion of muscular resting time of the trapezius muscle. We also found a high proportion of awkward wrist postures in the transducer wrist in all three techniques; in one due to prolonged flexion, and in the others due to prolonged extension. Other work tasks were less static, and were performed with higher upper arm and wrist velocities. Conclusion: None of the three echocardiography techniques was optimal concerning physical workload. Thus, to achieve more variation in physical load we recommend that the equipment be arranged so that the sonographer can alternate between two different techniques during the workday. We also propose alternation between echocardiography and nonsonographic tasks, in order to introduce variation in the physical workload. Clinical expertise should be used to achieve further improvements.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.437-440
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• 1997

The association of poor body postures with pains or symptoms of musculoskeletal discorders has been reported by many researchers. An ergonomic evaluation of postural stresses as well as biomechanical stresses is also important especially when a job involves highly repetitive or prolonged poor body postures. The human body is divided into five parts: shoulder/upper arm, lower arm/wrist, back, neck, lower extremities. A work-sampling based macropostural classification system was developed to characterize various postures in this study. Application of the posture classification schema developed in this study to 7 automobile assembly tasks showed that the schema can be used as a tool to didntify the operation and tasks involving highly stressful body postures. This posture classification schema can also be applied as a basis for quantitive evaluating the workload of manual task.

• Journal of the Ergonomics Society of Korea
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• v.35 no.2
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• pp.67-74
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• 2016

Objective: The aim of this study is to develop a farming shovel to reduce workload, which helps farmers lower the risk of musculoskeletal disease. Background: Most of work using farming tools including shovels requires repetitive works and awkward postures on body parts, and it could possibly cause work-related musculoskeletal disorders. It is necessary to develop and distribute farm equipment and tools in order to reduce physical workload. Method: To improve the most uncomfortable task perceived by ten farmers during the work with a shovel, the improved shovel was designed and made as a prototype for experiment for the comparison of the existing and improved shovels. Twenty males were recruited for this experiment, and muscle activity (%MVC) of six body parts and subjective discomfort ratings by body parts while working with a shovel were measured. A paired t-test was performed to compare physical workload between the existing shovel and the developed one. Results: A shovel applying foothold tied between shaft and blade was designed, which can help workers reduce repetitive bending of back and pressures for upper limbs while digging soil. According to compared evaluation of the developed shovel and the existing shovel, the developed shovel's %MVCs in all experimental muscles were significantly lower than those of the existing shovel. The developed shovel showed the biggest drop in perceived subjective discomfort rating of back, followed by arm and neck, compared to the existing shovel. Conclusion: It was confirmed that attaching a foothold to a shovel was an effective way of reducing workload in back and upper limbs during digging. Application: In the near future, if we put the prototype of developed shovel to practical use after making up for defects, it will help farm work environment be healthier and safer.

• Journal of the Ergonomics Society of Korea
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• v.29 no.1
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• pp.139-144
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• 2010

Grape weeding work requires Ergonomics improvement, because it performs motion likely to cause Musculoskeletal disorders (MSDs) repeatedly and continuously. The object of this study was to reject workload in Grape weeding works raised MSDs with the Moving Rail-chair and Electromotive Scissors. As objective method of analysis, we used heart rate, EMG, RULA, REBA. As subjective method of analysis, we used questionnaire that indicate lethargy area of body, pain of muscle and bone. As a result, working with Moving Rail-Chair and Electromotive Scissors is lower heart rate and EMG than typical working. Also for the subjective evaluation, reducing of neck and shoulder movement makes improve workload.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.4
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• pp.33-40
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• 2012

Dentists are known to be highly exposed to the musculoskeletal disorders (MSD). The present study investigated the prevalence of MSD among Korean dentists and association between their MSD and physical workload. In addition, detailed causes related to the physical workloads were identified in dental operation, and needs for improvement of dental instrument and environment were collected from Korean dentists. The standardized Nordic questionnaire was used to survey body troubles and three types of questionnaires were made to investigate the physical workloads, causes of the physical workloads and improvement priority of dental equipments, respectively. A total of 104 Korean dentists were participated in the survey. Neck trouble (82%) was the most prevalent in Korean dentists, and shoulder (68%) and low back trouble (56%) followed, while low back trouble was reported to be most frequent in previous studies. The body troubles were related to the physical workload of the corresponding body parts, although they were not associated with personal characteristics. Most Korean dentists selected 'to keep direct view inside patient's mouth' and 'no support of the hand with dental instruments' as the causes of awkward and strenuous work postures. They wanted design improvement for some equipment in their operating room such as operating light and arrangement of workplace.

• Korean journal of aerospace and environmental medicine
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• v.31 no.2
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• pp.31-32
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• 2021

In Vol. 31, No. 2, our journal prepared a review article, two original papers, and three case reports. First, autonomous systems are increasingly being introduced in aircraft systems. Therefore, it is crucial that flight crews are trained to adapt and handle these autonomous systems better. Consequently, we discussed crew resource management for handling autonomous systems. The fatigue of aviation workers is one of the biggest threats to aviation safety. Therefore, we analyzed the degree of fatigue in commercial aircraft pilots and evaluated the relationship between fatigue and their workload and the effect of fatigue on sleep. Since obesity has a significant impact on the health of aviation workers, we also comparatively analyzed the prevalence of obesity in Korea and Japan based on the data from the National Health and Nutrition Examination Survey. We defined cases that are difficult for aviation medical examiners to evaluate. This issue included cases of peripheral dizziness and tinnitus, cases of atopic dermatitis treated with biological agents, and cases of malignant tumors.