• 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.27 no.4
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• pp.96-100
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• 2012

Low back pain (LBP) is a major issue in modern industrialized society which is mainly caused by manual material handling (MMH) tasks. The objective of this study was to provide scientific data for establishing work standard for Korean workers throughout the laboratory experiment including some specific lifting tasks. Thirty male college students were recruited as participants. The maximum voluntary contraction (MVC), recommended weight limit (RWL), and psychophysical safety weight using Borg's CR-10 scale were studied. Results showed that the RWL was 8.4% MVC higher than the proposed psychophysical safety weight. Based on this result, it is suggested that the NIOSH lifting equation (NLE) should not be directly applied to Korean without reasonable modifications. The ratio of psychophysical safety weight to MVC was ranged from 20.1 to 26.4%. It is expected that use of the methodology in this study may provide better expectation of the work ability of Korean for reducing lower back pains caused by MMH.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.151-157
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• 1996

Postural tremor of the upper arm in a static posture was measured to provide guidelines of hand tool weight. Three types of camera recording postures were selected. Postural tremor was measured on five levels of tool weights; no weight, 400g, 800, 1200g, and 1600g. For each conditions, upper arm postural tremor was measured together with EMG of biceps, deltoid, and pectoralis major, and Borg's CR-20 scale ratings of perceived exertion. Results of the experiment are as follows; Frequency analysis of tremor revealed that increased amplitude of frequency band of 2-4Hz and 10-14Hz was observed. Postural tremor of the upper arm maintained the initial level until fatigue developed. After the development of fatigue, the rate of the change of postural tremor was significantly increased. Different tool weights and hand postures showed different rate of tremor increase. And time to fatigue and the corresponding endurance time was positively correlated with Borg's RPF scores.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.67-79
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• 2007

The objective of this study is to investigate a perceived discomfort and cause of Korean elderly in various activities such as work and leisure as well as in daily activities. 120 subjects (30 female and 30 male for each age: the young and elderly) participated in the interview type of questionnaire. Each participant answered to 41 items of activities of daily living. The examination of each item was progressed with 3 steps: whether to do the activity or not, degree of activity discomfort, and the reasons or causes of discomfort. Borg's CR10 scale is used to measure the degree of discomfort of daily activities. As a result, there are differences for the proportion of performers between two age groups, except for essential activities such as individual maintenance and housekeeping. The elderly complained about their daily activities more than the young did, and the degree of discomfort of women was significantly larger than that of men with aging. There are seven items, the mean degree of discomfort of which is over three points for the elderly, and they showed significant difference between two age groups. It was the important reason that physical capacities such as muscle strength and suppleness are declined. The results showed the characteristics of Korean elderly in the whole daily activities. These will be used to understand various life styles of them and to propose a field or direction of study related to the aging.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.105-110
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• 2008

This study focused on the decreased effect of the work load on using the lower extremity supporter in kneeling posture. Fatigue measures included subjective discomfort ratings through the use of the Borg's CR-10 scale based parameters. The resting period and work method were considered as independent variables. The break time conditions are grouped into 10 seconds after work for 1 min and not exist break time. The method of work conditions are divided into four types. There are kneeling with the lower extremity supporter, kneeling with the knee protector, just kneeling and squatting. The result of the ANOVA of the shift value of subjective discomfort showed the followings: 1) There were differences as regards to the method of the work, the break time and the part of body($p{\leq}0.05$). 2) The lower extremity supporter showed the least subjective discomfort in other part of body except the upper leg.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.99-104
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• 2013

With diversity of mobile services (e.g., messenger, and social network service) on smartphone, the demand of text input using a soft keyboard is increasing. However, studies on subjective and physiological responses of users for various touch locations are lacking. The present study investigated the ergonomic effects according to touch locations of a soft keyboard on smartphone. The experiment of the present study measured perceived discomfort using Borg's CR-10 scale and electromyography (EMG) on forearm (abductor pollicis longus, and extensor digitorum communis) and thumb (abductor pollicis brevis, and first dorsal interossei) muscles. Perceived discomfort was significantly varied from 0.7 (extremely weak discomfort) to 2.5 (weak discomfort) depending on touch locations. %MVC according to touch locations was only significant at abductor pollicis brevis which varied from 10% to 23%. The experimental results of the present study can be utilized in the ergonomic design of a soft keyboard.

• 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 the Korean Society of Safety
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• v.16 no.1
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• pp.79-83
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• 2001

Posture of the upper limbs in field works is known to be an important risk factor associated with CTD(Cumulative Trauma Disorders). In particular, uncomfortable posture and highly repetitive works in shipbuilding industry(for instance, sand blasting, grinding and blast painting, etc) made workers exposed to a great risk of injuries. The purpose of this paper is to analyze recruitment pattern of the muscles according to posture(joint angle displacement) during grinding. In this study, EMG signals of pectoralis major, latissimus dorsi, and posterior deltoid muscle were measured and analyzed from FlexComp EMG solution. And subjective ratings of perceived exertion were made using Borg's CR-10 rating scale.

• Journal of Korean Academy of Medicine & Therapy Science
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• v.10 no.2
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• pp.73-80
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• 2018

Objective: We developed an ergonomic pruning shears that allows the user to freely adjust the width of the grip and conducted this study to examine the effects of the pruning shears on grip strength and the fatigue of the fingers. Method: The maximum grip strength was first measured with an digital dynamometer, and the maximum grip strength was measured again after the subjects repeated scissoring 100 times using general pruning shears or ergonomic pruning shears. Borg's CR-10 scale was used to measure subjective fatigue after using the two pruning shears. Results: When the grip strength values after using the two pruning shears were compared with each other the mean grip strength after using ergonomic pruning shears was 27.69 kg, which was higher than that after using general pruning shears, 25.73 kg (p<.05). The subjective fatigue when the two pruning shears were used was shown to be 3.6 points for general pruning shears and 1.73 points for ergonomic pruning shears (p<.05). Conclusion: After repeating scissoring 100 times, the fatigue of the fingers was lower when ergonomic pruning shears were used than when general pruning shears were used and grip strength was higher when ergonomic pruning shears were used than when general pruning shears were used.

• Journal of the Korean Society of Safety
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• v.23 no.2
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• pp.30-36
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• 2008

This paper suggests the best work conditions, including short break time and number of mouse clicks on a computer, to prevent MSDs(Musculoskeletal Disorders) on VDT(Visual Display Terminal) work. Discomfort measures are calculated according to the Borg's CR-10 Scale. The short break time conditions are grouped into 7, 15, and 30 seconds after every 10-minute work period and the number of mouse clicks are divided into 10 clicks/min, 20clicks/min, and 30clicks/min. The result of the ANOVA on the shift value of subjective discomfort shows the following: 1) Regarding the break time and the number of mouse clicks, there are statistical differences between the measured values for the neck and the wrist(p<0.05). 2) Regarding the number of mouse clicks, there are statistical differences between the measured values for the shoulder and the forearm(p<0.1). 3) Regarding the break time and the number of mouse clicks, there are no statistical differences between the measures values for the eyes, upper arms and back(p<0.1).