• Annals of Clinical Neurophysiology
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• v.2 no.2
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• pp.95-100
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• 2000

Purpose : Primary writing tremor(PWT) can be classified as either type A or type B depending on whether tremor appeared during writing or whilst writing and also on adopting the hand postures normally used for writing. Through the clinical experience author has had an impression that PWT type B may not be purely dependant on specific writing postures. The objective of this study was to clarify whether PWT type B have writing posture-specificity or not. Results : The data indicated that type B PWT is not writing posture-specific. Various pronation and supination postures could evoke tremor as well as writing postures. Furthermore most of other pronation- and supination-related tasks could evoke tremors as well as action of writing. Conclusions : The present data suggest that PWT should be limited only on the pure form of task-spesific PWT type A.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.05a
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• pp.307-312
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• 1998

In forklift operations, awkward postures due to backward driving may put drivers to the risk of CTD or low back pain. In this research, 6 forklift drivers were surveyed with OWAS for objective posture evaluation and bodymaps for self-report evaluation. The backward driving happened more frequently than forward driving as expected, and, as work hours passed by, the drivers naturally tended to assume the easier work postures in inverse proportion to the frequency of the backward operations. According to the results of OWAS, 60 % of the work postures in the forklift operations belonged to the category II, III, and IV classified serious. Especially, in the backward driving, the postures with the neck twisted over $45^{\circ}$ occupied 82.4 %. In addition, discomfort on the neck, left shoulder, and low back was frequently reported in the self-reports.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.139-148
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• 2015

For design research of teenagers' posture correcting shirt, postures of teenagers were analyzed and became the base of inventing suitable patterns. The subjects of this study were 198 of both female and male middle school students from the city of Seoul. Students' postures in classroom and length change of body surface were observed and analyzed; based on this, total of 5 postures was selected, and length changes of body surface were applied. The patterns in this study were designed with stretch material to help antagonism by muscle movements. Each fabric that was used in this study had 110% of stretch, 120~140% of stretch, and 150~170% of stretch. Both of one-way-fabric and duplex-fabric were used in this study, depending on application site.

• 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.16 no.2
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• pp.73-82
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• 1997

Daily exposure to constrained body postures and deviations from neutral postures over a long period may result in discomfort as well as pains and aches in the muscles, joints, tendons, and other soft tissues. Furthermore, it was known that poor body postures are a major cause of musculoskeletal disorders in industry. Therefore, in this study, comfort ranges of joint motions were obtained as a criterion for evaluating body postures and designing workplaces ergonomically, which were bases on subjects' perceived discomfort level estimated by magnitude estimation. Nineteen healthy male subjects participated in the laboratory study. They results showed that comfort ranges of joint motions occurred in the wrist, elbow, neck, and ankle were little less than their normal range of joint motions, but those in the back(L5/S1) and hip joint were much less than their normal ones. This fact implies that the back and jip movements are more stressful than the other joints movements. It is expected that comfort ranges of joint motions can be used as a valuable guideline when designing and evaluating workplaces.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.178-183
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• 2002

The purpose of this study was to quantitatively investigate the effects of external load upper extremity posture on perceived discomfort. An experiment was conducted for measuring discomfort scores depending upon external loads and upper extremity postures, in which the free modules and numeric estimate method of the magnitude estimation was adopted as a tool for obtaining discomfort ratings. The upper extremity postures were controlled by wrist flexion/extension, elbow foexion, shoulder flexion, and shoulder adduction/abduction. The results showed that all experimental variables except shoulder adduction/abduction were significant at ${\alpha}$=0.01 or 0.05. The effect of external load was very much larger than that of upper extremity postures. Therefore, it is recommended that a new posture classification scheme taking effect of external load to into consideration be developed for quantifying postural load.

• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.99-105
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• 2021

Vehicle occupant postures are anticipated to vary more widely during automated driving and to become more significant in terms of the autonomous vehicle safety. Experimental and computational approaches are needed to investigate and evaluate occupant behaviors during automated driving in general. However the validity and effect of such occupant postures are unknown, thus it is necessary to examine occupant behaviors and injury countermeasures for various occupant postures. This study was focused on the development and evaluation of restraint system model for occupant behavior examinations in the first step according to autonomous vehicle occupant safety. The finite element models of dummy and restraint system were set up and simulation results showed overall model performance and safety tolerances of different reclined occupant postures during frontal impact loading.

• Physical Therapy Korea
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• v.15 no.4
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• pp.80-86
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• 2008

Cross-legged sitting postures are commonly assumed during computer work. The purpose of this study was to determine the effects of leg crossing on trunk muscle activity while typing at a computer. Trunk muscle activity was measured in three 8 different sitting postures, in random order. These posture were: normal sitting with a straight trunk and both feet on the floor (NS), upper leg crossing (ULC), and ankle on knee (AOK). The right leg was crossed onto the left leg in both cross-legged postures. Twenty able-bodied male volunteers participated in this study. Subjects typed on a computer keyboard for one minute. Surface electromyography (EMG) was used to record bilateral muscle activity in the external oblique (EO). internal oblique (IO), and rectus abdominis (RA). The EMG activity of each muscle in the NS posture was used as a reference (100% EMG activity) in relation to the two cross-legged postures. Muscle activity in the right EO. right IO, and left IO was significantly lower in the ULC posture than in the NS posture. In contrast, muscle activity in the right RA was significantly higher in the ULC posture than in the NS posture. Muscle activity in the tight RA was significantly higher in the AOK posture, as compared to the NS posture, whereas activity in the left IO was significantly lower in the AOK posture, as compared to the NS posture. The right-left muscle activity ratios in the EO and IO showed significantly different patterns in the cross-legged postures, suggesting that asymmetrical right-left oblique muscle activity had occurred.

• Science of Emotion and Sensibility
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• v.8 no.1
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• pp.29-36
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• 2005

This study investigated which recumbent posture can give rise to the highest vagal modulation in patients with coronary artery disease(CAD), among three recumbent postures; namely, the supine, left lateral, and right lateral postures. For this purpose, 43 patients as CAD group and 31 patients as control group were studied. Heart rate variability(HRV) was measured on these patients for three recumbent postures in random order Normalized high-frequency power was the highest, whereas normalized low-frequency power was the lowest in the right lateral postures, among the three recumbent postures.

• Journal of the Ergonomics Society of Korea
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• v.29 no.6
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• pp.933-942
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• 2010

Objective: To develop an ergonomic evaluation tool which can be apply to assess the lower-limb postures associated with farming tasks. Background: In general, most of existing ergonomic assessment tools was developed to investigate the work-related musculoskeletal disorders of the upper-limb postures in manufacturing industry. Methods: As the first step of development of the evaluation tool, 13 lower-limb postures that were commonly observed in farming task were investigated by the subjective discomfort ratings, heart rates, and muscle activities. And then, an ergonomic evaluation tool for the lower-limb postures was developed based on results of the first experiment. Lastly, the ergonomic checklist which was developed in the current study was compared with other existing ergonomic assessment tools. Results: Based on the results of comparisons between a newly developed assessment tool and other existing assessment tools, it was found that a newly developed tool can perceive more sensitively for the various lower-limb postures than other assessment tools. Conclusions: Lower-limb posture assessment tool which can evaluate and assess risks of lower-limb WMSDs which were prevalent in farming tasks more easily and accurately was developed in this study. The lower-limb assessment tool can also be utilized to prevent WMSDs related with lower-limbs as well as improve working environments.