• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 추계학술대회논문집
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• pp.109-113
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• 1995

This study was designed to investigate the effects of work postures and anthropometry on the musculoskeletal discomfort of the telephone operators involved in VDT tasks. The level of musculoskeletal discomfort were evaluated for 279 VDT operators from three different workplaces. The work postures and the anthropometric data were evaluated for 70 VDT operators out of the total of 279 operators. Multiple regression analysis was utilized to examine the relation- ship between the measured ergonomic variables and the level of the musculoskeletal discomfort. It is evident from the result of the study that the ergonomic factors have great influences on the level of the musculoskeletal discomfort.

• 산업공학
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• 제16권2호
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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.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 춘계학술대회논문집
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• pp.90-94
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• 1997

Many workers like welders are working in squat sitting postures with te object on the ground for an entire work shift. It is suspected that such prolonged squat sitting without any supporting stool would gradually cause musculoskeletal injuries to workers. This study is to quantitatively evaluate the physical stress caused by the prolonged squat sitting and to recommend a safe work/rest schedule for the task with squat sitting posture based on the lab experiment. In this study, 8 healthy student subjects participated in the experiment. They maintained a squat sitting posture for 16 minutes with 4 different stool height conditions: no stool, 10cm hight, 15cm height, 20cm height. Every 2 minutes, the discomfort was subjectively assessed using the magnitude estimation method for the whole body, lower back, upper leg and lower leg. Based on discomfort rating, we found that 10cm height stool relieved the workload most. Discomfort rating results also indicated that 20cm height stool showed the heghest workload, and that there was no difference in workload between 15cm height and no stool. We recommend to provide the workers with 10cm height stool for prolonged squat sitting tasks.

• Industrial Engineering and Management Systems
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• 제7권1호
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• pp.90-98
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• 2008

This research selects the lifting task to be the main subject. Four experiments were designed to measure which among lifting postures, lifting heights, waist-belt, and breathing control significantly influences intra-abdominal pressure (Gallagher, 1991; Lavender, Andersson and Natarajan, 1999). The experimental results were taken to be the recommendations of the manual materials handling work design. The research findings reveal that the symmetrical stoop posture is the most significant to the intra-abdominal pressure within all lifting postures. When the lifting height is increased, the intra-abdominal pressure produced relatively goes up. Also, the combination of symmetrical stoop posture, waist-belt use, and inspiration and holding at the same time is the most efficient in carrying out lifting tasks. Simultaneously, the research discovers that for any posture, the volume of the intra-abdominal pressure is much bigger when using the waist-belt compared to when it is not used. Therefore, the waist-belt design for the lifting works might be the future research approach.

• 로봇학회논문지
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• 제18권1호
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• pp.110-116
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• 2023

In this study describes the design of Exo-suit to assist those who work in unstructured positions. The present study aimed to analyze various types of work, especially those performed in unstructured postures by heavy industry workers. Based on the motion capture analysis results, an attempt was made to develop a shoulder muscle-assistive Exo-suit capable of assisting a wearer who is working using shoulder muscles. In the present study, as the first step of developing a shoulder muscle-assistive Exo-suit, different working scenarios were simulated, and the corresponding motion data were estimated using motion capture devices. The obtained motion data were reflected in the design of the Exo-suit. The main structure of the shoulder muscle-assistive Exo-suit was made of a carbon fiber-reinforced composite to obtain the weight reduction. The shoulder muscle assistive Exo-suit was designed to fully cover the range of motion for workers working in unstructured postures.

• 대한인간공학회지
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• 제30권4호
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• pp.481-489
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• 2011

Objective: The aim of this study was to develop an ergonomic checklist (AULA: Agricultural Upper-Limb Assessment) which can assess the risks of the work-related upper limb disorders of farming tasks in Korea. Background: There are few assessment tools that reflect the current condition of agricultural works as of now. Method: AULA was developed as following three stages. First of all, a physiological experiment was conducted with selected 14 upper limb postures which are frequently occurred in farming tasks and then, an ergonomic checklist was developed with determining risk levels of each body posture based on the experimental findings. Lastly, the ergonomic checklist was validated by comparing with the existing assessment tools. Results: When comparing the AULA which was developed in this study with the existing assessment tools, it was found that the AULA may get over limits of the existing ones which are sensitive to particular postures, but aren't sensitive to the rest of them. Conclusion: It is predicted that the developed upper limb posture assessment tool which gets over the existing tools' limits and is proper for domestic farm work conditions, will help to reduce musculoskeletal disorders caused by farm works, by assessing farm works more easily and objectively. Application: By further developing the theoretical groundwork on the induction of muscular skeletal system symptoms relating to agricultural works, it is expected to improve the level of preventing and managing such muscular skeletal system symptoms in the field of agricultural and farming works, which is relatively less advanced in terms of labor difficulties.

• 대한가정학회지
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• 제49권3호
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• pp.113-121
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• 2011

This study developed a method of calculating dynamic wearing ease (DWE) to make patterns for coverall work clothing. The DWE was measured from 3D body scan data of women in their 20's (n = 10). The body postures adopted for measuring the DWE were sitting and deep bending postures. Three types of experimental patterns (A, B, C) were developed. The DWE was applied at the waist and hip lines of the pattern. The location and size of the DWE varied from one pattern to another. For pattern B, DWE of 8.8cm was applied at the back of the waistline. For pattern C, 5.3cm was applied at the waist for the center back line, and 3.5cm was applied at the under hip level. The comfort of the experimental clothing was evaluated in six body postures. The results showed that patterns B and C were comfortable at the crotch, shoulders, and arm pits. Pattern C was comfortable at the hip and crotch areas in the arms lifting-up posture and the stepping-up posture. The appearance and fit of the experimental clothing were evaluated by the panels. Patterns B and C fitted better than pattern A at the abdomen. The results suggest that DWE should be applied at the waist and hip levels for making coverall work clothing patterns.

• 대한인간공학회지
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• 제30권2호
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• pp.349-356
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• 2011

Objective: The purpose of this study was to analyze the risk factors of the musculoskeletal workload of mid-old-age female caregivers by identifying work postures and subjective symptoms. Method: This study was carried out on a total of 206 subjects 206 mid-old-age caregivers(45~65 years old) from November 2009 to April 2010: 206 mid-old-age caregivers (45~65 years old) at the long-term hospital. A questionnaires survey on general factors and subjective symptoms of subjects was conducted. The risk factors of the musculoskeletal workload evaluation method is based on OWAS, RULA, REBA according to occupation properties. Results: The analysis of the rates of the subjective symptoms showed that 78.6% subjects experience low back pain. The analysis of the work type showed that transfer is the highest rate(36.3%) and position change is the second(18.2%). The analysis of the work postures showed that the thrusted back with twisting position over $20^{\circ}$ is highest rate(37.4%), the bended back forward with twisting position is the second(27.5%). Conclusion: This study suggested that the need of preventive education for caregivers and workload improve. It is hoped that subsequent study on the difference of subjective symptoms between educated caregivers and non educated caregivers will be conducted.

• 대한가정학회지
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• 제40권11호
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• pp.193-205
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• 2002

To evaluate farmers' workload during harvesting grapes in summer, this study investigated farmers' physiological, psychological responses, work postures and thermal environment around in the field. This field study was conducted in the Anseong County of Kyonggi Province at the end of August. Five career farmers (1 male, 4 females) volunteered as subjects. Three of them were over their sixties. During harvesting grapes in the field, physiological responses were monitored continuously. 1. Air temperature (T/sub a/), air humidity(H/sub a/), black globe temperature(T/sub g/), air velocity and WBGT around the grape field were 26.9℃, 77.7%RH, 32.8℃, 0.08㎧ and 26.3℃, respectively. Because farmers started the harvesting task in early morning, thermal environments weren't conditions to give farmers severe heat strain. 2. The percentage of the work postures was larger in order of standing, walking, and bending one's back posture. Particularly, the percentage of standing posture with raising both arms above shoulder of two farmers was up to 29% and 61% of the total work duration. 3. Rectal temperature (T/sub re/), mean skin temperature (T/sub sk/), clothing microclimate temperature (T/sub cl/) on the chest and the back, heart rate (HR) and energy expenditure (EE) were 37.2℃, 33.1℃, 32.0℃, 32.4℃, 88bpm and 1.3 Kca1/㎡/min respectively. In the point of these physiological results, we evaluated that the harvesting task was a moderate work. 4. All farmers expressed‘hard, hot, humid and slightly uncomfortable’ at the end of works for each subjective questionnaire. The grape harvesting tasks were not evaluated as a very hard work in the point of physiological work standards. But we considered 1) inappropriate work posture (standing posture with raising both arms above shoulder) and 2) farmers' age as burden factors. These findings suggest that adding adequate protective clothing/equipments for farmers may contribute to maintain their body temperature within the normal range, stabilize HR and decrease psychological strain.

• Safety and Health at Work
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• 제7권1호
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• pp.49-54
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• 2016

Background: Prolonged sitting leads to low back discomfort and lumbopelvic muscle fatigue. This study examined the characteristics of body perceived discomfort and trunk muscle fatigue during 1 hour of sitting in three postures in office workers. Methods: Thirty workers sat for 1 hour in one of three sitting postures (i.e., upright, slumped, and forward leaning postures). Body discomfort was assessed using the Body Perceived Discomfort scale at the beginning and after 1 hour of sitting. Electromyographic (EMG) signals were recorded from superficial lumbar multifidus, iliocostalis lumborum pars thoracis, internal oblique (IO)/transversus abdominis (TrA), and rectus abdominis muscles during 1 hour of sitting. The median frequency (MDF) of the EMG power spectrum was calculated. Results: Regardless of the sitting posture, the Body Perceived Discomfort scores in the neck, shoulder, upper back, low back, and buttock significantly increased after 1 hour of sitting compared with baseline values ($t_{(9)}=-11.97$ to -2.69, p < 0.05). The MDF value of the EMG signal of rectus abdominis, iliocostalis lumborum pars thoracis, and multifidus muscles was unchanged over time in all three sitting postures. Only the right and left IO/TrA in the slumped sitting posture was significantly associated with decreased MDF over time (p = 0.019 to 0.041). Conclusion: Prolonged sitting led to increased body discomfort in the neck, shoulder, upper back, low back, and buttock. No sign of trunk muscle fatigue was detected over 1 hour of sitting in the upright and forward leaning postures. Prolonged slumped sitting may relate to IO/TrA muscle fatigue, which may compromise the stability of the spine, making it susceptible to injury.