• Fashion & Textile Research Journal
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• v.19 no.4
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• pp.504-514
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• 2017

Discomfort as well as muscular pain and musculoskeletal diseases occur in cases of stressed posture due to prolonged pressure. Therefore, the American Academy of Orthopaedic Surgeons (AAOS) and Pediatric Orthopaedic Society of North America (POSNA) recommend that bags that weigh no more than 15 - 20% of the wearer's weight. However, despite the prolonged pressure from using baby carriers, there are no recommendations and limited studies on how to protect wearers. Therefore, this study investigates subjective fatigue according to the usage of waist support and hip seat. Based on this, muscle fatigue and secondary subjective fatigue according to three types of currently commercial baby carriers (X-type, H-type, and H-hip type) were measured. Subjective comfortability was evaluated on a 5 point Likert-scale and subjective fatigue was evaluated on Borg's CR-10 scale. Objective muscle fatigue was also compared by measuring and analyzing electromyogram (EMG). The results of primary subjective fatigue showed statistically significant changes in the shoulders, waist, calves, and soles of the feet according to the usage of hip seats and waist support. Electromyogram measurements also showed less muscle fatigue at the upper trapezius muscle and thoracic erector spine muscle for the H-hip seat baby carrier, which has both waist support and hip seat, compared to an X-type baby carrier, which has neither. However, results of subjective fatigue showed opposite results at the waist despite having same results at the shoulders and beneath the shoulders. This show discrepancies between objective muscle fatigue and subjective fatigue; therefore, that both aspects must be taken into consideration when developing ergonomic baby carriers.

• Korean Journal of Human Ecology
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• v.24 no.2
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• pp.255-266
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• 2015

In this study, we have developed the ergonomic pattern from the 3D human body reflecting cycling posture and extensibility of the stretch fabrics. Adjusting pressure level in the construction of athlete's tight-fitting stretch garments by reducing the original pattern is a challenging subject, which influence on the performance of the wearer directly. Therefore, in this study, relationships between the reduction rates of the 2D pattern obtained from the 3D human scan and resultant clothing pressure were explored to improve the fit and pressure exerted by reduced clothing pattern. Subjective wear sensations of the experimental garments were rated using a seven-point Likert scale on two consecutive days. While wearing the garments, subjects were asked to take five different postures including waist flexion, sitting and others. A Likert-type scale was used for the evaluation, with 7 points indicating the best fit in tight-fitting pants. Comparing 2/3T-pattern with T-pattern, the latter was superior to 2/3T-pattern in terms of adhere well to the waist and hip area in the 0.032 significance level. T-pattern was superior to 2/3T-pattern in terms of fitting and wear comfort. As results, the pattern obtained from the flexed body reflecting cycling posture already included the contraction and extension of the skin while cycling posture, so that the extra ease for movement and good fit was not need to be considered. The optimized reduction rates were determined with the proposed reduction rate, the resultant pressure range was within the range of $0.5{\sim}3.0gf/cm^2$ at eight locations on the body except front waist band and thigh band.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.9-20
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• 2013

Background: This study was conducted to provide preventive measure for the musculoskeletal disorders in automobile parts manufacturing workers. Method: The author surveyed to the musculoskeletal symptoms prevalence and its related factors from 10th to 17th April 2011 with structured self administered questionnaires. 223 out of 225 collected questionnaires were used for final analysis, excluding 2 questionnaires with no valid response. Based on the diagnostic criteria of NIOSH (National Institute for Occupational and Health), an investigation was made into the prevalence of musculoskeletal symptoms as well as into the factors related to individual items. Results: The prevalence of musculoskeletal symptoms according to the criteria of NIOSH was the highest in the shoulder (52.9%), followed by the neck (39.%), the hand/wrist (35%), the waist (29.6%), the arm/elbow (24.7%), and the leg/food (23.8%). One-way analysis showed that among general characteristics, age was the musculoskeletal risk factor with the greatest effect. Whereas among work-related characteristics, significant risk factor didn't find. Yet it was shown that among ergonomic work postures, high degree of musculoskeletal risk was shown by the posture involving frequent and repetitive movement of the arm and the hand/wrist and also by the posture involving standing for a long time. Multiple regression analysis showed that musculoskeletal risk was 1.795 times higher in those age 50 and over than in those under age 50; 1.67 times higher in the high risk stress group than in the low risk stress group; and 1.131 higher in the group involving the repetitive use of the hand/arm than in the other groups (p<.05). Conclusion: The prevalence and stress score of automobile parts manufacturing workers were higher than other occupation workers. Among general characteristics, drinking and smoking were shown to be related to stress score; while age was shown to have significant effect on musculoskeletal risk.

• Journal of Biosystems Engineering
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• v.36 no.1
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• pp.58-67
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• 2011

A high prevalence of protected horiculture farmer's work-related musculo-skeletal disorders (MSDs) have been reported in precedent studies. One of the tasks required ergonomic intervention to reduce the musculo-skeletal risks is the task of harvesting. The purpose of this study is to evaluate quantitatively the spinal load of worker harvesting with squatting posture to predict and prevent musculo-skeletal risks. Spinal load in Squatting posture with asymmetric trunk motion were analyzed. Before evaluating spinal load on harvesting worker by bio-mechanical approach, it is needed to validate human model. In this study, ADAMS LifeMOD human model shows satisfactory results, comparing with already validated model's results or measured results. While worker reached arms (20%, 40%, 70% arm reach) with various asymmetric trunk motion (0, 45, 90 degree), their spinal loads (extension, twisting and lateral bending moment) were evaluated. In case of extensor moment at lumbo-sacral joint, the more the arm reach got increased, the moment increased. however, in case of twisting moment and lateral bending moment, the more both arm reach and asymmetric trunk motion got increased, the moment increased significantly. The findings of this study suggest that it need to be determine the spinal load, especially twisting, lateral bending moment in evaluating musculo-skeletal workload in squatting posture.

• Journal of Biosystems Engineering
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• v.34 no.4
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• pp.286-294
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• 2009

A high prevalence of protected horticulture farmer's work-related musculo-skeletal disorders (MSDs) have been reported in precedent studies. One of the tasks required ergonomic intervention to reduce the musculo-skeletal risks is the task of product transporting. The purpose of this study is to evaluate quantitatively the spinal load of operator using manual vehicles to predict and prevent musculo-skeletal risks. Spinal load in operators using 4 kinds of manual vehicle were analyzed. Before evaluating spinal load on operator using the manual vehicles by bio-mechanical approach, it is needed to validate human model. In this study, ADAMS LifeMOD human model shows satisfactory results, comparing with already validated model's results or measured results. While Operators pushed the manual vehicles(wheelbarrow, Trolley, 2 wheel cart, and 4 wheel cart) contained loads that were 0 N and 800 N, their spinal loads(compression force, shear force) were evaluated. The compression force demonstrated under the NIOSH action limits - 3410N - for all 4 manual vehicle's operators(McGill 1997; Marras 2000). However, the lateral shear force demonstrated over the University of Waterloo - 500N - for all 3 manual vehicle's operators except 4Wheel cart (Yingline and McGill, 1999). Therefore, operators have risks in prevalence of the musculo-skeletal disorders due to shear force. The findings of this study suggest that it need to be determine the spinal load, especially lateral shear force in designing the manual vehicles in the future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.101-110
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• 2007

This study was performed to find out hazardous factors in the loaded works of muscular skeletal disorders(MSDs) for four company attached to dining workers from October 2005 to June 2006. The results are summarized as follows. 1. 42.5% of workers in study group were 40-50 years old, and females were higher than males, and the average of body weight was 70kg, 57kg in males and females, respectively. Working time per day was mostly 7-9hours, and the rate of worker who had never education and training was 46%. 2. The upper part and right part of body were higher than lower part and left part in symptoms of muscular skeletal disorders. Body parts which complained of symptoms were the order of right shoulder(55%), right arm(54%), right hand,(40%) waist(35%), leg(25%), and neck(24%). 3. The results of evaluation in the loaded works of muscular skeletal disorders to cooking, dish supply, preparing side dish, and washing the dishes and cleaning the floor of cooking room using RULA and OWAS checklists was action level 4(potential hazards, needs of change workplace), and the result of evaluation using back compressive force needed control measures as 779.27 lbs~1,274.04 lbs. In a view point of the result of this study, large dining rooms should be designed by ergonomic technology for the work surface height, width, and depth. The height of carrying car should be lower to 70cm, and repetitiveness and handling weight should be reduced by mechanical means, and education and training also should be performed for all of workers positively.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.106-111
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• 2015

Purpose: Impaired reaching movement is commonly observed in children with cerebral palsy. The purpose of this study was to determine whether the inclination of seat surface can influence the reaching movement in children with spastic diplegic cerebral palsy (CP). Methods: The subjects were 31 children, 16 children with spastic bilateral CP and 15 typically developing (TD) children. The children performed static sitting and forward reaching under three conditions: a horizontal seat surface (Horizontal $0^{\circ}$), a seat surface inclined anterior 15 degrees (Ant $15^{\circ}$), and a seat surface inclined posterior 15 degrees (Post $15^{\circ}$). A 3-axis accelerometer ('ZSTAR3') was used for analysis of the reaching movement. A 3-axis accelerometer was attached on the manubrium of the sternum, lateral epicondyle of the humerus, and styloid process of the ulna. We measured the reaction time, movement time, and data amount during reaching the 8 cm target with an index finger on the three inclined seat surfaces. Results: Reaction time and movement time for CPs showed significant delay; comparing the TD's and CP's amount was significantly greater than the TD's during reaching task (p<0.05). In particular, CP's reaction time and movement time on a seat surface inclined Ant $15^{\circ}$ was significantly more delayed compared with the other seat surfaces (p<0.05). Conclusion: Our results suggest that seat-inclination intervention may provide an ergonomic approach for children with spastic cerebral palsy.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.608-621
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• 1993

The Purposes of this study were 1)to find the body surface total line and segment line significantly(${\alpha}$=0.05) changed by the leg movement including all movement direction of hip joint, knee joint and ankle joint for the more functional clothing. 2)to classify them into 3 types-expansion type, contraction type, expansion & contraction type, and 3)to identify the characteristics of the body surface length changes. 10 Crosswise and 5 lengthwise body surface total lines and 48 crosswise & 39 lengthwise body surface segment lines of 26 female college students aged from 18 to 24 years were measured directly on the body surface and were analyzed by ANOVA & Multiple Comparison Test (Tukey). The results were as following : Body surface total lines significantly changed were all the body surface total lines except abdoman girth, 1/2thigh girth of lower leg and ankle girth, and these were classified into 3 types : Center front leg line belonged to expansion & contraction type, whereas lateral leg line, legscye girth, and total crotch length belonged to contraction type. The rest belonged to expansion type. Knee girth showed maximum expansion, whereas center front leg line showed maximum contraction. Body surface total lines have shown large expansion crosswise whereas lengthwise they have mainly shown contraction. At least more than one component segment line of each body surface total lines except abdoman girth and ankle girth have shown significant change. Top segment of inner leg line showed maximum expansion. whereas just below top segment of center front leg line showed maximum contraction. Crosswise all the body surface segment lines have shown expansion except inner back segments of thigh girth and 1/2thigh girth of upper leg which have shown contraction. Lengthwise they have shown both expansion and contraction according to the location of front or back, and below or upper 1/2thigh girth line except the component segment lines of lateral leg line, which has shown contraction only.(cf. figure 2. figure 3. and table 2-2).

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.2
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• pp.271-286
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• 2015

This study presented functional designs for development of functional compression wear for men in their forties based on body muscles as well as designed 2D patterns using 3D standard body form data of men in their forties. Patterns with an optimal stretch rate were proposed through a comfort evaluation. Different material was used for different areas such as the sports ability strengthening areas including body parts that often move for sports (such as the shoulders, abdomen and lower arm), areas that require ventilation for perspiration (such as the chest and back center, and armpits), and stable form areas (such as the chest, waist and elbows). The front and back surface areas of the developed pattern was an average 102.4% size compared to the body surface area. The results indicated that the 90% reduction pattern showed changes in pressure value according to area of movement, had the best breathability when worn, and had the best, most comfortable fit compared to the other subjects. The clothing pressure values of the pattern were around 22.1-23.4mmHg for the arm area (which has a big movement range and has many muscles) and 10.4-11.8mmHg for chest and abdomen areas related to major organs and breathing, indicating appropriate clothing pressure. A compression wear top pattern with pressure appropriate to the target age range and excellent appropriateness for the body form will be developed for men in their forties. A study method will be proposed to develop design technology for ergonomic compression wear tops with excellent fit and comfort.

• Journal of the Korea Furniture Society
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• v.22 no.3
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• pp.151-159
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• 2011

This study is to suggest versatile chair designs that are organically shaped to take individual orientation. This study intends to provide design method to ensure the face of the chair that contacts the body of its user is transformed flexibly to support the body. The movement of human body is not just a behavior but the ways and tools that reflexively express against external stimuli that are sensed and identified by the person. The versatile chair whose users' sitting position is fixed is made by covering the lump form with a piece of cloth ensuring that the content is firmly fixed and by placing the beads-woven wood fabric according to the shape. And then, it is covered with the external cover. The proposed versatile chair designs assume specific forms as follows: First, it is a versatile chair whose user's sitting position can fix. The organically-shaped form that can accept varying postures is made as a mass, which changes into different shapes when human body touches the form so that users can lie down or sit. Due to such transformation, body posture is determined and individual differences in shape changing are all acceptable. Second, it is a versatile chair that reflects the user's position in a fixed chair, where a cloth-wrapper feature is applied to the form a sifit wrapped postures so that a variety of body postures can be accepted. Finally, a versatile chair that reflects the user's position by changing the shape of is covered with forms so that it will be transformed and used in accordance with situations and chair shapes and reflect multiple shapes including round or square ones.