• Korean Journal of Occupational Health Nursing
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• 제26권3호
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• pp.133-141
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• 2017

Purpose: The purpose of this study was to identify the relationship between work-related characteristics and job stressors and the factors influencing musculoskeletal symptoms of the warehouse employees. Methods: The research was a cross-sectional, descriptive study. Data were collected from 319 warehouse employees who agreed to participate in the study by using self-report questionnaires. Data were analyzed using descriptive statistics, $x^2-test$, and logistic regression analysis (SPSS 18.0). Results: The overall prevalence of musculoskeletal symptoms was 37.6%. The logistic regression analysis revealed a posture that renders fatigue or pain, repetitive work, and a higher total score of job stressors as the risk factors for musculoskeletal symptoms in many body parts. Conclusion: Employers should plan to educate employees who work in warehouses about the correct working posture to prevent musculoskeletal diseases, stop repetitive work, and manage job stressors.

• Journal of the Korea Safety Management & Science
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• 제8권3호
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• pp.77-86
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• 2006

After conducting an investigation of a specific workplace, 372 labor workers, who are employed at a certain domestic petrochemical company valve operating and maintenance processing section, were personally questioned about specific work-related ailments. According to the results, 57% of workers who were working in the petrochemical industry have suffered from pain-related musculoskeletal disorders in, at least, more than 1 body part. Specifically, there are more than 28% of workers suffering from pain in more than two body parts. Among the total work population, 18.8 % of workers are assumed to have a high probability of being diagnosed with musculoskeletal disorder. Also, according to the RULA checklist which evaluates environmental improvement conditions of the workplace, 76.7% of workplaces among the inspected areas have high hazardous work factors that are related to musculoskeletal disorder and needs to be improved upon and observed right away or in the foreseeable future. The prior factor has a high correlation and pain rate which is due to an improper work posture. Originally, this improper work posture is caused mostly by ergonomically incorrect facility design. Furthermore, the structure of the workplace does not consider the worker's individual build.

• Journal of the Korean Society of Safety
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• 제31권4호
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• pp.111-119
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• 2016

This study aimed to analyze postures that were frequently conducted in manufacturing industry. To find grip strength and muscle activities of each posture, Maximum Voluntary Contraction (MVC) and ElectroMyoGraphy (EMG) were measured. Based on the results of this study, the most appropriate posture could be suggested and used as a basic information for preventing musculoskeletal disorders. Most work-related musculoskeletal disorders have been occurred in the fields of manufacturing industry. According to previous studies, it was reported that the rate of musculoskeletal diseases of upper extremity was higher than that of other body parts. Accordingly, there were many studies about discomfort and grip strength of upper extremity. However, these studies dealt with single selection of wrist, elbow and shoulder. So, it was insufficient for comprehensive studies about upper extremity. And in order to improve the work posture, the physiological changes being generated by the combination of wrist, elbow and shoulder postures should be observed and analyzed. In order to conduct this study, thirty university students who had no records of MSDs involved were recruited. Independent variables were postures of wrist(pronation, neutral, supination), postures of elbow(flexion $45^{\circ}$, $90^{\circ}$) and postures of shoulder(flexion $0^{\circ}$, $90^{\circ}$). And dependent variables were MVC values and EMG values. Jamar dynamometer and TeleMyo 2400T G2 was used to measure MVC and EMG. MVC and EMG for 12 postures were measured for three second and for three times. Experiment was performed randomly. A 10 minutes rest period was provided after each t. To measure muscle load, the EMG signals of eight muscles (Biceps, Medial triceps, Lateral triceps, Brachioradialis, Extensor carpi ulnaris, Extensor carpi radialis, Flexor carpi ulnaris and Flexor carpi radialis) were evaluated. MVC values and EMG values were analyzed using Minitab ver. 14. The results showed that MVC value was the highest at shoulder $0^{\circ}$, elbow $45^{\circ}$ and wrist supination. In case of wrist postures, MVC of supination is the highest. In case of elbow and shoulder postures, MVC of flexion $45^{\circ}$ and $0^{\circ}$ was the highest. It was found that there were interaction between wrist and elbow posture under shoulder flexion and between shoulder and wrist under elbow flexion $45^{\circ}$. In case of the angle of shoulder $0^{\circ}$, elbow $45^{\circ}$ and wrist supination, the EMG values of four muscles(Medial Triceps, Extensor carpi ulnaris, Extensor carpi radialis, Flexor carpi ulnaris) were the highest. Based on this study, it is worth to note that the combination postures of upper extremity have a large impact on the MVC and EMG. The optimal condition upper extremity was shoulder flexion $0^{\circ}$, elbow flexion $45^{\circ}$ and wrist supination for preventing work-related musculoskeletal disease.

• Journal of the Ergonomics Society of Korea
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• 제31권3호
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• pp.437-444
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• 2012

The purpose of this study was to suggest appropriate human model for ergonomic evaluation considering working postures on 3D space. Background: Traditionally extreme design rules have been widely utilized at the stage of designing products. Body size of 5th percentile and 95th percentile in stature has been generally selected for controllability and clearance evaluation, respectively. However, these rules had limitations in reflecting working posture in ergonomic evaluation. Method: In order to define working posture on 3D space, not only sagittal plane but also lateral plane was considered. Kinematic linkage body model was utilized for representation of working posture. By utilizing the anthropometric data of 2,836 South Korean male populations, the point cloud for end points of linkage models was derived. The individuals who were lacking in certain controllability were selected as human models for the evaluation. Result: In case of standing posture it was found that conventional approach is proper for all controllability evaluations. Contrary to standing posture, tall people had less controllability on control location below shoulder point in sitting posture. Conclusion: From the derived proper range on controllability, ergonomic evaluation rule was suggested according to working posture especially in standing and sitting. Application: The results of the study are expected to aid in selection of appropriate human model for ergonomic evaluation and to improve the usability of products and work space.

• Journal of the Korean Society of Safety
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• 제20권2호
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• pp.127-132
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• 2005

The purpose of this study is to compare representative posture classification schemes of OWAS, RULA and REBA in terms of correctness for postural load. The comparison was based on the evaluation results by the three methods for 224 working postures sampled from steel, electronics, automotive, and chemical industries. The results showed that OWAS and REBA generally underestimated postural stress than RULA irrespective of industry type, work performed and whether or not leg posture is balanced. While about $71\%\;and\;73\%$ of the 224 posture were evaluated with the action category/level 1 or 2 by OWAS and REBA respectively, about $60\%$ of the postures were classified into the action level of 3 or 4 by RULA. The coincidence rate of postural stress category between OWAS and RULA was just $33.5\%$, while the rate between RULA and REBA was $46.0\%$. It is concluded from the findings of this study and the previous research that compared to OWAS and REBA, RULA more precisely evaluates postural stress.

• Journal of Practical Engineering Education
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• 제16권2호
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• pp.115-119
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• 2024

With the increase in the number of ICT industry workers, there is a demand for research on preventing VDT syndrome. However, existing posture correction products mostly rely heavily on cameras or sensors in wearable devices. In this paper, we have developed a posture correction system that utilizes built-in cameras and circular pressure sensors to collect posture information. Additionally, the system provides a personalized service by capturing the correct posture of the user initially and monitoring the user's posture based on that input. By precisely correcting postures during users' daily tasks, this system aims to prevent and improve VDT syndrome, ultimately enhancing the efficiency of ICT industry workers.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• 제25권2호
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• pp.57-64
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• 2019

Background: This study was designed to identify the effect of the taping on the forward head posture during computer work. Methods: Twenty healthy adults were statistically assigned into 2 groups, the taping group (n=10) and the control group (n=10). In order to induce delayed onset muscle soreness (DOMS), twenty subjects performed isometric exercise of the neck on Bobath table for 20 minutes. During the experiment, subjects in taping group were attached Kinesio-tape on their upper trapezius. By using 2-D motion analysis, measurements were taken before taping, at 24 hour, 48 hour, and 72 hour after inducing DOMS. The effects of taping were evaluated by the angle of the head. Results: The results of this study were as follows; 1) There was no significant difference between the taping group and the control group (p>.05). 2) The control group had no significance, but the taping group shown a significance on the angle of head during computer work (p<.01). The interaction of group x period also shown a significance (p<.01). Conclusion: From these result, it was revealed that the taping therapy on upper trapezius could improve the angle of head during computer work.

• Physical Therapy Korea
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• 제13권4호
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• pp.39-46
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• 2006

The purpose of this study was to determine the effects of slump sitting postures on the masticatory, neck, shoulder, and trunk muscles associated with work-related musculoskeletal disorders (WRMD). Eleven healthy adults (age, $23.3{\pm}2.7$ yrs; height, $174.0{\pm}4.1$ cm; weight, $61.4{\pm}6.6$ kg) participated in this study. The participants were free of injury history and neurologic deficits in the masticatory, neck muscles and upper extremities at the time of participation. The subjects were asked to perform erect and slump sitting postures under the guidance of physical therapists. The surface electromyography (EMG) was recorded from the anterior temporalis, masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique, gluteus maximus muscles of 11 adults as they performed visual terminal display work, which are known as the weakened and tightened muscles owing to WRMD. The recorded signals were averaged and normalized to the mean amplitude of the EMG signal obtained during submaximal reference voluntary contractions. The results of study were as follows: The masseter, upper trapezius, serratus anterior, middle trapezius, L3 paraspinal, external abdominal oblique muscles significantly differed in the slump sitting posture (p<.05). The muscle activities of the serratus anterior, middle trapezius muscle, and external abdominal oblique were significantly lower and that of the masseter, upper trapezius, L3 paraspinal muscles were significantly higher. Further research is needed to assess the motor control problems and the function of the deep muscles in posture stability of patients with WRMD.

• The KIPS Transactions:PartB
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• 제18B권5호
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• pp.305-314
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• 2011

Research into the visual perception of human emotion to recognize an intention has traditionally focused on emotions of facial expression. Recently researchers have turned to the more challenging field of emotional expressions through body posture or activity. Proposed work approaches recognition of basic emotional categories from body postures using neural model applied visual perception of neurophysiology. In keeping with information processing models of the visual cortex, this work constructs a biologically plausible hierarchy of neural detectors, which can discriminate 6 basic emotional states from static views of associated body postures of activity. The proposed model, which is tolerant to parameter variations, presents its possibility by evaluating against human test subjects on a set of body postures of activities.

• Journal of the Ergonomics Society of Korea
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• 제23권4호
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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.