• Journal of the Ergonomics Society of Korea
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• v.23 no.4
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• pp.45-56
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• 2004

The purpose of this study is to evaluate perceived discomfort of working postures in terms of upper body (back, shoulder, and elbow) flexions when an external load varies. Eighteen subjects participated in an experiment of appraising perceived discomfort of varying upper body postures with three levels of external loads given. The ANOVA results showed that the perceived discomfort of upper body postures was significantly affected by the external load. It was also apparent that the interactions between external load and upper body posture were significant (p< 0.001). The result implies that a new posture classification scheme for workload assessment methods may be in need to reflect such interactions between external load and upper body posture. In order to support the statement, a regression model of perceived discomfort of upper body postures obtained from the experiment was developed and compared to that of perceived discomfort of seven work-related postures found in automobile assembly operations. The correlation coefficient between predicted and actual values of perceived discomfort was about 0.96. It is expected that the result help to properly estimate the body stress resluting from worker's postures and external loads and can be used as a valuable design guideline on preventing work-related musculoskeletal diseases in industry.

• IE interfaces
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• v.10 no.3
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• pp.197-208
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• 1997

In workplace design, an ergonomic solution should ensure low postural stress in the operator during his/her work. Stress caused by awkward working postures of the trunk, shoulders and legs can result in fatigue, discomfort, musculo-skeletal disorders and nerve entrapment syndromes. Since discomfort and musculo-skeletal disorders are both related to exposure to biomechanical load on the musculo-skeletal system, minimization of discomfort will contribute to reduction of the risk for musculo-skeletal disorders as well. Therefore, in this study, perceived discomfort on the human body joints was measured in the standing postures using the magnitude estimation in order to have a standardized numerical scale for joint discomfort. Nine healthy graduate students participated voluntarily in the laboratory study. The results revealed that perceived discomfort of all the joints increased as the joints deviated from neutral position. Especially, it showed drastic increment on perceived discomfort when deviation from neutral position in each human body joint increased from 75% to 100%. in terms of relative range of motion(R0M). On the basis of these experimental results, a preliminary ranking for assessment of stressfulness of non-neutral postures around the human body joints was suggested.

• Korean Journal of Computational Design and Engineering
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• v.15 no.5
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• pp.333-342
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• 2010

This paper describes a novel quantitative discomfort evaluation method based on motion data and its application to discomfort analysis of ingress/egress motions for cars. To develop the discomfort evaluation model, we introduced the discomfort regression curve and the range of motion for each degree-of-freedom of the joints of a whole human body. The maximum discomfort value for the joints at a specific time is selected to represent the discomfort value of the whole body at the time. The results of the experiments and questionnaires support the claim that our discomfort measure matches experimental subjective discomfort levels.

• Journal of the Ergonomics Society of Korea
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• v.30 no.6
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• pp.695-703
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• 2011

Objective: This study was to investigate the effects of coordinated upper-limb body postures on the subjective discomfort rating, heart rate, and muscle activities. Background: Although generally many checklists such as OWAS, RULA, and REBA were applied to evaluate various body postures, the body postures were might be overestimated or underestimated because each body part(i.e., back, shoulder, and elbow etc.) was evaluated separately, and then added all rates of individual body parts to assess an overall risk level for the body posture in these methodologies. Methods: A total of 20 participants maintained 14 postures which were combinations of back, shoulder, and elbow flexion angles and then muscle activities, subjective discomfort, and heart rates were collected every three minute during a sustained 15 minute and 0.5kg weight holding task. Four muscle groups were investigated: erector spine, anterior deltoid, upper trapezius, triceps brachii. Results: Results showed that subjective discomfort was the lowest when the angle of back and shoulder were both $0^{\circ}s$, while the body posture with $45^{\circ}$ of back angle and $45^{\circ}$ shoulder angle was rated as the most subjective discomfort posture. In general, the subjective discomfort ratings increased as back and shoulder flexion angles increased. It was noted that, however, the subjective discomfort of body posture with a $45^{\circ}$ back angle and $45^{\circ}$ shoulder flexion angle was lower than that of body posture with a $0^{\circ}$ back and $45^{\circ}$ shoulder flexion angle. The research findings of heart rates and muscle activities showed similar results for the analyses of subjective discomfort ratings. Conclusions: The possible limitations of the current ergonomics evaluation techniques which assessing a body posture with summing all body part score after individually analyzed in this study. Based on the analyses of subjective discomfort, heart rate, and muscle activities, it was recommended that a use of effects of coordinated upper-limb body postures would be considered when one evaluates work-load for various working postures. Application: These findings can be used for developing a more accurate assessment checklist for working posture as well as preventing musculoskeletal disorders of workers in workplaces.

• Physical Therapy Korea
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• v.14 no.2
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• pp.85-90
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• 2007

In many manufacturing occupations, industrial workers reported foot or lower leg problems such as discomfort, pain or orthopedic deformities. This study investigated the effects of two different working conditions upon assembly worker's perception of discomfort and foot pain associated with various body parts. Twenty-three male volunteers performed work in the factory. Ergonomic intervention has been to modify the flooring in an attempt to alleviate the problems associated with constrained standing and walking work. The worker's standing conditions consisted of standing on a hard floor while wearing shoe insoles. Questions were asked regarding body discomfort and foot pain. Significant differences in body discomfort and foot pain were found when comparing the overall effects of wearing shoe insoles on a hard floor (p<.05). This investigation indicated that shoe insoles reduced body discomfort and foot pain (p<.05).

• KIEAE Journal
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• v.7 no.5
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• pp.29-34
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• 2007

Discomfort glare from windows is an important issue in window and daylighting design. This study aims to investigate the effect of luminance difference between the lower and the upper part of a large glare source. Experiments were conducted using a luminous body divided into two parts, the upper part and the lower part. The degree of discomfort glare from the luminous body was examined. The result shows that the part with lower luminance is perceived as a glare source when the part has higher luminance then the background luminance. The degree of discomfort glare was estimated for the experimental conditions, and compared to the observations. The estimation was made using two methods: one summed the glare sensation for each section, and the other used the average luminance of the whole luminous body. The result of the comparison shows that the method using the average luminance has approximate values to the observations. Consequently, the use of the average luminance was proposed for evaluation of discomfort glare from non-uniform large glare sources.

• Journal of muscle and joint health
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• v.17 no.2
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• pp.212-221
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• 2010

Purpose: The purpose of this study was to determine the effects of music therapy (Jang-Gu) on depression, stress, pain and body discomfort in women with osteoarthritis. Methods: The study is designed using one group pretest-posttest experimental design. 31 arthritis patients, the subjects of the group participated in the music therapy program. The program was provided for 12 weeks (two times per week). The questionnaires were used to measure the outcome variables before and after the program. Data were analyzed with the SPSS 17.0 using descriptive statistics, paired t-test. Results: Depression, Stress, Pain did not decrease. But body discomfort decreased (p=0.001). Conclusion: Therefore this program was effective in body discomfort and can be a community based self-help management program for arthritis patient.

• Journal of Environmental Science International
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• v.14 no.2
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• pp.215-220
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• 2005

Thermal neutrality is not enough to achieve thermal comfort. The temperature level can be the optimal, and still people may complain. This situation is often explained by the problem of local discomfort. Local discomfort can be caused by radiant asymmetry, local air velocities, too warm and too cold floor temperature and vertical temperature difference. This temperature difference may generate thermal discomfort due to different thermal sensation in different body parts. Therefore, thermal comfort can not be correctly evaluated without considering these differences. This study investigates thermal discomfort sensations of different body parts and its effect on overall thermal sensation and comfort in air-heating room. Experimental results of evaluating thermal discomfort at different body parts in an air-heating room showed that thermal sensation on the shoulder was significantly related to the overall thermal sensation and discomfort. Although it is known that cool-head, warm-foot condition is good for comfort living, cool temperature around the head generated discomfort.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.7 no.1
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• pp.16-29
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• 2000

The purpose of this study was to examine the effects of a warmed blanket on relieving the cold discomfort after Cesarean Section delivery. A nonequivalent control group pre-test/post-test design was used for this quasi-experimental study. Sixty women were recruited for this study and divided by two groups: experimental and control groups. Blankets warmed to $40^{\circ}C$ were applied to the women in the experimental group for one hour and unwarmed blankets were applied to the control group. Using Abbey's shivering scales, subjective thermal sensation score, and Celsius mercury thermometer, cold discomfort was measured at four time points: 1) baseline measure (at the point the blanket was applied) 2) 15 min. later, 3) 30 min. later, and 4) 45 min. after application. Data were analyzed using SPSS/WIN and t-test and MANOVA were used to examine the effects of the warmed blanket for relieving cold discomfort. The results of the study are as follows. The experimental group had less cold discomfort than the control group(Wilts's value =0.580, p=0.000) at the 45 minute point after blanket application. the Experimental group reported less shivering and subjective thermal sensation than the control group. Shivering scores showed significant differences between the two groups at each of the four time points (baseline, 15 min., 30 min., and 45 min.) and subjective thermal sensation score showed significant differences between two groups at 45 minutes. after blanket application. In conclusion, the application of a warmed blanket was more effective on shivering and subjective thermal sensation than body temperature measured by objective means. Because women in this study were in the normal range of body temperature, differences in the objective body temperature between the two groups may not be sensitive enough to be detected. Even though differences in objective body temperature were not found, reduced subjective discomfort for low body temperature may be a sufficient significant finding in for nurse clinicians to utilize this method on their practice. Further studies in this area are needed to support these findings.

• Journal of the Ergonomics Society of Korea
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• v.28 no.1
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• pp.9-19
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• 2009

Repetitive movement, inadequate working posture, overuse of force, physical contact with sharp edge, vibration and temperature were well known risk factors of WMSDs (Work-related Musculoskeletal Disorders). Many researchers have investigated the relationship between inadequate working postures and incidences of WMSDs of the upper extremities, whereas relatively few researchers have tried to evaluate workload associated with the lower-body postures. The effects of lower-limb postures including various knee flexion angles on the subjective discomfort, heart rate and EMG of lower-limb muscles were investigated in this study. Thirty graduate students were asked to maintain thirteen different body postures, and heart rate and EMG data of five muscle groups (electro spine, biceps femoris, vastus medialis, gastrocnemius and tibialis anterior) from each posture were collected during fifteen minutes sustaining tasks. All participants were also asked to report their discomfort ratings of body parts. Results showed that high subjective discomfort ratings and heart rates were reported at the postures of knee angles of $60^{\circ}$ and $90^{\circ}$, whereas low discomfort ratings were founded at the postures of chair heights with 20cm, 40cm, and sitting with crossed legged. The change of median frequency for each muscle group during fifteen minutes tasks was investigated for each body posture to evaluate the relationship between muscle fatigue and body posture. It was found that the trends of changes of median frequency were different based on muscle group as well as lower-limb body posture from this study.