• Journal of the Ergonomics Society of Korea
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• v.24 no.2
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• pp.65-70
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• 2005

Evaluation of repetitiveness for upper extremity intensive tasks is essential to determine the level of risk for upper extremity musculoskeletal disorders at the workplace. However, experimental data available to establish the acceptable levels of repetitiveness for various postures and forces is lacking. The present study examined the maximum acceptable frequencies(MAFs; motions/min.) of shoulder, elbow, wrist, and index finger motions at different forces(1kgf and 4kgf for shoulder, elbow, and wrist; 0.25kgf and 1 kgf for index finger) in sitting. Seventeen right-handed males in 20s without having any history musculoskeletal disorders participated in the MAF experiment. The participants determined their MAFs for the upper extremity motions by using the self-adjustment method and their work pulse(increase in heart rate; beats/min.) and rating of perceived exertion(RPE) were measured when working at MAF. The MAFs of elbow, wrist, and index finger motions for each force level were about 2, 3, and 6 times the corresponding MAF(9 at the high force and 24 at the low force) of shoulder motion and the MAFs at the low force increased about 2 times those at the high force. The work pulses of elbow, wrist, and index finger motions for each force level were 70%, 50%, and 30% of the corresponding work pulse(17 at the high force and 12 at the low force) of shoulder motion and the work pulses at the low force were about 70 % of those at the high force. Lastly, the RPEs of the upper extremity regions were about level 3(moderate) or below.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.5
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• pp.852-859
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• 1996

The factors and mechanism of arm surface changes were analyzed by regression analysis for the relationship between changes in arm joint angle and arm surface changes, according to the direction of upper extremity motion. Body surface change patterns among subjects were tested also. Experiments were carried out on 3 female subjects of different body types to examine 26 motions in 4 directions for 4 upper extremity parts. The major conclusions of the study are as follows: 1. The expansion or contraction of arm surface length depends on the direction of upper extremity motion. 2. Arm surface length changes by linear expansion or contraction according to the joint angle of the direction of motion. The mechanism of arm surface changes is represented by a linear relation between arm surface changes and the (actors of the direction of upper extremity motion and arm joint angle. 3. Arm surface length shows the same pattern of body surface changes regardless of body type. A quantitative model of body surface changes at upper extremity should be developed for functional sleeve design.

• Journal of the Korean Society of Clothing and Textiles
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• v.46 no.4
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• pp.613-623
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• 2022

This study developed a functional prototype jacket designed to reduce loads on the upper extremities of workers performing repetitive motions in the same posture for extended periods of time. Dynamic taping lines were applied to the upper extremities, and three dimensional (3D) supporters were inserted in the abdomen and back waist areas corresponding to the core muscles. Clothing pressure on the upper-extremity dynamic taping lines was set to two levels (proto P1 and proto P2), and the 3D supporters were designed in three types (proto FW, proto FW/BW, proto FW/BW/BBX). According to the subjective pressure perceived on each part of the upper extremities, the level proto P1 pressure was preferred. The proto FW/BW/BBX 3D supporter was rated as excellent, and the perceived pressure was ranked as satisfactory. The prototype jacket performed upper-extremity load reduction when the upper-extremity clothing-pressure level was set to 1.8 kPa, 2.1 kPa, and 2.4 kPa on the upper arm, forearm, and wrist regions, respectively, and when 3D supporters were installed in the abdomen and back of the waist with the addition of a back band.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.185-204
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• 2003

The purpose of this study was to obtain the data for stable and accurate techniques of the free throw in basketball. The subjects of this study were seven male basketball player consisted of college students athletes. Free throw motions were taken by video camera. The three-dimensional coordinates was processed by DLT. The variables were the velocity, the angular velocity of the upper extremity segments, degree, and angular momentum. The result of analysis is summarized as follows. 1. The velocity and angular velocity of the upper extremity segment was showed an gradual increase and a smooth velocity transfer, transferring from proximal segment to distal segment at free throw motion in basketball. 2. The local term and remote term angular velocity momentum of the proximal segment showed larger than that of the distal segment in X, Y, Z axis component all. 3. The remote term angular momentum was showed larger than that of the local term angular momentum in X, Y, Z axis component all. 4. The angular motion of the upper trunk and upper arm, upper arm and forearm was showed in opposite direction and symmetrical angular momentum in local term angular momentum of the Y and Z axis component. 5. All the segments of upper extremity segment was showed left rotation in remote term angular momentum of the Y axis component and right rotation in remote term angular momentum of the Z axis component.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.2 no.1
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• pp.45-49
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• 2009

This paper proposes a data glove for a rehabilitation robot interface for the upper extremity paralysis. The designed data glove uses seven flexible sensors so as to measure the flexion angles of fingers and wrist. We verified the performance of the data glove using a 3D graphic interface developed. The experimental results show that the proposed data glove is feasible to sense hand motions and applicable to the robot interface.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.6
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• pp.911-923
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• 1995

The zone of expansion and contraction of arm surfaces was analyzed, the correlation between arm surface changes was studied, and ergonomic sleeve designs were presented in which the consideration of body surface changes is emphasized. Experiments were carried out which include 43 upper extremity segments, 21 motions and 35 female subjects. The major conclusions of the study are as follows : 1. As a sleeve drafting method, detailed measures should be applied on the base of the sensitivity of body surface changes. The range of arm surface changes can be divided into three zones : concentrated expansion zone, zone of little change, and contraction part. The maximum expansion zone was the upper part of elbow. 2. The correlations were higher in lengths than in circumferences. Arm lengths were mainly correlated with upper arms. The more detailed the arm surface was, the lower the correlations between surface changes were. So there was not a lot of relation between segment changes. Tendency of body surface changes depended on the anatomical structure of the upper extremity and the movements of arm muscles. 3. As an application of measures and ease, ergonomic sleeve designs weve presented in which arm surface changes were considered. Ergonomic sleeve designs are recommended for working clothes and sports wear.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.5
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• pp.826-841
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• 1995

This study is concerned with the functional utility of movement in sleeve from an ergonomic viewpoint. Experiments were carried out which include 43 upper extremity segments, 21 motions and 35 female subjects. The major conclusions of the study are. 1. The expansion rate of upper extremity was higher in length than in circumference mesurements. The amounts of expansion were, especially high (more than 60mm) for inner arm length, axillary arm circumference, and outer arm length. Therefore, a lot of ease is necessary for these parts. On the other hand, armhole circumference, forearm circumference, and wrist circumference had low rates of expansion. The sleeve cap length was also contracted in all motions. 2. The expansion rate and the range of expansion and contraction were higher in the upper arm than in the forearm. The main points of expansion were the axillary and elbow parts. The segment of maximum expansi (rate of 44.8%) was Iii of axillary parts. As the body surface expands mainly in some segments, it is desirable to allow ease to the main segments of expansion. 3. In a basic sleeve, necessary ease was lacking in the measurements for outer arm length and axillary arm circumference, while it was too large in armhole circumference, forearm circumference, wrist circumference, and sleeve cap length. Therefore, a basic sleeve is inadequate as a functional sleeve for hard work in point of functional utility of movement. Wider application of these findings would lead to an improvement in the comfort of workers.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.400-408
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• 2022

Objective: The purpose of this study is to compare EMG activity during horticulture motion and upper limb rehabilitation motion, to confirm whether horticulture motion is suitable for upper extremity rehabilitation of hemiparesis. Design: Three-group cross-sectional design. Methods: The 45 subjects were divided into three groups: hemiparesis (n=15), elderly (n=15) and healthy (n=15). We have recorded EMG signals of six upper limb muscles Upper trapezius (UT), Middle deltoid (MD), Anterior deltoid (AD), Biceps brachii (BB), Triceps brachii (TB), Brachioradialis (BR) during horticultural motions and three upper limb rehabilitative motions. The dependent variables were peak EMG, integral EMG, co-contraction ratio. A two-way repeated measures ANOVA was used to compare the horticultural motion and rehabilitation motion of the three groups. Results: The peak EMG was significantly different in MD, AD, BB, TB according to the motion(p<0.05), and the UT, BB were significant differences according to the group(p<0.05). The integral EMG was significantly different in MD, AD, BB, TB, BR according to the motion(p<0.05), and the BB were significant differences according to the group(p<0.05). The co-contraction ratio was significantly different in TB/BB according of the motion, and there was no difference between the groups. Conclusions: As a result of this study, horticultural motion alone was insufficient for upper arm rehabilitation, and horticultural motion alone was insufficient to induce continuous activity of the forearm.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.519-524
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• 2023

The purpose of this study is to construct basic data for efficient technical training by investigating the difference in muscle activity during badminton technical movements involving jump motions similar to game situations. Seven male badminton players were randomly assigned to perform smash, drop, and clear techniques, and electromyograms were measured during the implementation of three technical movements. Measured EMG was calculated by RMS and one-way ANOVA was performed. The muscle activity of the smashing motion did not show any significant difference according to the site. In drop motion, activity of PM in the upper extremity muscles was lower than that of BC and ECR, and FCR activity was lower than that of EC. The activity of ECR was higher than that of PM and FCR. The activity of ES in trunk muscles was lower than that of RF and GM. RF activity of lower extremity muscles was higher than that of ES and BF. In clear motion, the activity of TC in upper extremity muscle was higher than FCR. The activity of ES in trunk muscles was lower than that of BF. RF activity of lower extremity muscles was higher than that of BF, and BF activity was lower than that of RF and GM. The activity of GM was higher than that of BF. As for muscle activity according to badminton skills, smash and drop motions were higher than clear motions in FCR, and clear motions were higher than smash and drop motions in RA. In conclusion, it is considered that muscle activity during the badminton game is different according to the characteristics of each skill, and FCR can affect the smash and drop, and RA can affect the clear motion.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.786-791
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• 2007

Statistical differences between men and women are investigated for a total of eleven joint motions during level walking. Human locomotion which exhibits nonlinear dynamical behaviors is quantified by the chaos analysis. Time series of joint motions was obtained from gait experiments with ten young males and ten young females. Body motions were captured using eight video cameras, and the corresponding angular displacements of the neck and the upper body and lower extremity were computed by motion analysis software. The maximal Lyapunov exponents for eleven joints were calculated from attractors constructed and then were analyzed statistically by one-way ANOVA test to find any difference between the genders. This study shows that sexual differences in joint motions were statistically significant at the shoulder, knee and hip joints.