• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1575-1579
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• 2008

The purpose of this study was to investigate how maximum-effort eccentric exercise over different contraction ranges affects the characteristics of torque-angle relationship of human ankle plantarflexor in-vivo. Subjects were randomly assigned in two groups. One group (n=6) performed 120 maximum-effort eccentric ankle dorsiflexion contractions at short muscle length (ankle range of motion from -5 to 15 deg) and the other group (n=6) at long (ankle range of motion from 10 to 30 deg) muscle length. Eccentric exercise decreased the maximum isometric ankle plantarflexion torque ${\sim}40%$. It was found that the optimum ankle joint angle changed from 7.5 deg to 11.1 deg and 10.1 deg, shifted toward the longer muscle length, regardless of the exercise range. The results of this study suggest that eccentric exercise alters the characteristics of torqueangle relationship of the muscle but there is no differential effect of the eccentric contraction range.

• The Journal of Korean Physical Therapy
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• 제34권5호
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• pp.267-271
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• 2022

Purpose: This study examined the effects of a kettlebell and aqua bag on the gluteus maximus, gluteus medius, and vastus medialis lower extremity muscle strength during a one-leg deadlift, a top-down exercise. Methods: Twenty healthy adults were enrolled in the one-leg deadlift exercise under two conditions. The muscle activity of the gluteus maximus, gluteus medius, and vastus medialis was measured by surface electromyography (S-EMG). A paired t-test was used for statistical analysis, and the statistical significance criteria were set to p<0.05. Results: A comparison of the muscle activity according to the degree of contraction of the gluteus maximus revealed low muscle activity in AD exercise compared to KD exercise (p<0.05), and there was no significant difference in the gluteus medius and vastus medialis (p<0.05). Conclusion: These results suggest that when the one-leg deadlift exercise is performed according to the weight characteristics, the gluteus maximus is suitable for intervention using a kettlebell, and the gluteus medius and vastus medialis are more suitable for intervention by providing instability using an aqua bag.

• 한국의류산업학회지
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• 제20권3호
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• pp.343-352
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• 2018

The objective of this study is to investigate the market of fitness compression wear as well as to design an optimal fitness compression wear by analyzing the muscle and movement characteristics of the elderly women in Korea. In this regard, research for functional garments is needed to increase muscle activity of elderly people during physical exercise. Firstly, we investigated the brand, design, size, material, and pattern of fitness wear based on the market survey. Secondly, we identified preference, evaluation items, evaluation method, and pattern design method based on the literature review. Finally, in addition, the motion type, range, angle to improve the muscle strength of the elderly were investigated and the maximum muscle strengths of each motion were analyzed by using 2007 Size Korea data (n = 386). It is also designed for muscle fatigue through exercise and rapid fatigue recovery after exercise. The evaluation methods for fitness compression wear were classified as motor functionality, physiological comfort, pattern and material suitability evaluations. The muscle strength at leg (pushing force) and waist (lifting force) of the ages of 60 to 69 years old showed 239.3 N and 274.5 N, respectively, which were the lowest forces compared to younger age groups. By applying these results to the design process of fitness wear, it is anticipated that the fitness wear will have a proper fit to the body shape of elderly people in South Korea as well as it can increase muscle efficiency to promote physical capability and healthy life for senior people.

• 대한인간공학회지
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• 제32권3호
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• pp.217-227
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• 2013

Objective: The purpose of this study was to analyze 'response time', 'peak response time' and 'overshoot value' for each muscle by applying the EMG signal to the vehicle response in ISO 7401 and to quantify the response of the driver according to vehicle characteristics by comparing vehicle characteristics and muscle responses of the driver. Background: The Open-loop test defined in international standards ISO 7401 is the only method for evaluating the performance of the vehicle. However, this test was focused only on mechanical responses, not driver's ones. Method: One skilled male driver(22 yrs. experience) was participated in this experiment to measure muscle activities of the driver in transient state. Then the seven muscle signals were applied to calculate 'response time', 'peak response time', and 'overshoot value'. Results: In the analyses of the EMG data, the effects of vehicle type and muscle were statistically significant on the 'response time' and 'peak response time'. Also, the effects of vehicle type, muscle, and lateral acceleration level were statistically significant on the 'overshoot value' in this study. According to the analyses of the vehicle motion data, vehicle motion variable(LatAcc, Roll, YawVel) was statistically significant on the 'response time' and vehicle type, vehicle motion variable, and lateral acceleration level were statistically significant on the 'peak response time', respectively. Conclusion: In the analyses of the 'response time' and 'overshoot value', the data of muscle activities(EMGs) was better index that could evaluate the vehicle characteristic and performance than the data of vehicle motion. In case of peak response time, both EMG and vehicle motion data were good index. Application: The EMGs data from a driver might be applicable as index for evaluation of various vehicle performances based on this study.

• 대한물리의학회지
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• 제18권2호
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• pp.83-92
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• 2023

PURPOSE: This study examined the effect of using a smartphone according to the direction of wearing a bag on muscle characteristics and balance ability in adults in their 20s with chronic ankle instability. METHODS: Twelve people with chronic ankle instability were examined for three weeks. The types of carrying a bag were classified into three conditions: to the right, to the left, and on both sides. The muscle characteristics and balance ability were measured and analyzed. The one-way ANOVA was used to obtain a difference between conditions. RESULTS: A significant difference in the muscle tone of medial gastrocnemius was observed between the dominant group and the non-dominant group. The muscle tone and stiffness of the peroneus longus decreased significantly after walking with a smartphone and carrying a bag. The maximum slope of the forward and reverse directions increased and decreased significantly, respectively, after walking with a smartphone and carrying a bag on both sides. CONCLUSION: In this study, muscle fatigue causes a decrease in muscle tone and stiffness with chronic ankle instability when carrying a heavy back while walking, and there were asymmetric changes in the balance ability. Therefore, adults with chronic ankle instability should carefully avoid carrying a heavy bag for extended times, irrespective of the style or type of the bag.

• 한국염색가공학회지
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• 제26권3호
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• pp.181-186
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• 2014

This paper surveys improvement characteristics in muscle fatigue with bio-activity material imbedded fabric. For this purpose, the subjects wear the garment which is covered by bio-activity materials all over every day during 2 weeks of experimental period. After 2 weeks period, VAS(Visual Analogue Scale) index evaluation regarding muscle fatigue and pain has been conducted in comparison between before wearing and after so that we can evaluate the effect on muscle fatigue improvement. The effectiveness survey for testing products consists of improvement on krunkle, muscle fatigue and exercise capacity. As a result, 100% of test subject group completes a questionnaire with positive answer as above normal in every question. In addition the preference of testing products is researched in wearing comfort, activity and convenience. And it is marked above normal by 100% of test subject group as well. Moreover any kind of unusual skin reaction has not been detected in safety evaluation. Therefore this testing products is being judged as a beneficent product for improvement on muscle fatigue without any skin irritation.

• Journal of Korean Biological Nursing Science
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• 제21권2호
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• pp.152-159
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• 2019

Purpose: To understand awareness, attitude and knowledge levels of muscle health of adults over 18 years old. Methods: This study was a cross-sectional study using questionnaires. A total of 401 questionnaires were included for final analysis. Mean and standard deviation of the continuous variables were analyzed and frequency analysis of categorical variables was performed. To identify differences according to general characteristics, t-test was used. Results: Awareness scores about the importance of muscle health and exercises were 8.3 and 13.0, respectively. Attitude score and knowledge score were 12.4 and 15.0, respectively. There were differences in attitude toward muscle health according to gender, age, physical activity, and diet habits. However, there was no difference in attitude toward muscle health according to educational level, smoking, drinking, or sleeping. Conclusion: It is necessary to seek a strategy to improve awareness and attitude toward muscle health based on knowledge, not merely to raise knowledge level about muscle health. Since nurses play a central role in health promotion and disease prevention, they should also play an important role in strategic development and application of intervention.

• 대한물리의학회지
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• 제14권4호
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• pp.173-181
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• 2019

PURPOSE: This study examined the necessity of a musculoskeletal injury-prevention program for automobile parts manufacturing workers by assessing the body composition, muscle strength, and posture according to sex and age. METHODS: Two hundred eighty-two workers (men, 218; women, 64; mean age, 38.97 years; and mean work tenure, 10.29 years) participated in this study. They completed a questionnaire on their general characteristics, excluding personal identification codes. The participants were evaluated for body composition, muscle strength, and posture using InBody, a hand dynamometer, and the Image J program through photography, respectively. An independent t-test and one-way analysis of the variance were used for the comparisons according to sex and age, respectively. RESULTS: Significant sex-related differences in muscle strength and grip force were observed (p<.05). In addition, the left-side pelvic inclination was significantly higher in the female participants than in the male participants (p<.05). Significant age-related differences in the skeletal muscle mass and muscle strength were observed around 40 years (p<.05). Significant correlations were observed among the body composition (skeletal muscle and body fat masses), muscle strength, and posture (pelvic inclination; p<.01). CONCLUSION: Significant differences in pelvic inclination by sex and muscle strength by age were found, even in healthy workers. Additional posture and muscle strength measurements will be needed for workers who participate in the musculoskeletal injury prevention program because they are exposed to an incorrect posture for many hours or in many repetitive tasks.

• 한국정밀공학회지
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• 제26권6호
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• pp.122-130
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• 2009

The analysis of human movement requires the knowledge of the Hill type muscle parameters, the muscle-tendon and moment arm length change as a function of joint angles. However, values of a subject's muscle parameters are very difficult to identify. It turns out from a sensitivity analysis that the tendon slack length and maximum muscle force are the two critical parameters among the Hill-type muscle model. Therefore, it could be claimed that the variation of the tendon slack length and maximum muscle force from the Delp's reference data will change the muscle characteristics of a subject remarkably. A numeric optimization method to search these tendon parameters specific to a subject is proposed, and the accuracy of the developed algorithm is evaluated through a numerical simulation.

• 한국수산과학회지
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• 제45권5호
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• pp.430-437
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• 2012

The effects of low temperature and starvation on the physiochemical characteristics of the muscle of the olive flounder Paralichthys olivaceus, were examined. Fish were deprived of feed for 28 days at 2, 4, 6, 8, 10, 12, and $20^{\circ}C$ in order to establish suitable conditions for live fish transportation. Throughout most of the 4 weeks of feed restriction, the physiochemical characteristics of the muscle of olive flounder were found to be dependent on the acclimation temperature. The breaking strength of muscle did not show a significant reduction during feed restriction at 2 and $4^{\circ}C$. With increasing temperatures, however, the breaking strength of muscle differed significantly according to the individual and feed restriction period (P<0.05). The moisture content in muscle acclimated at 10, 12, and $20^{\circ}C$ increased steadily over the feed-restriction period, while the crude lipid content decreased during the same period (P<0.05). At water temperatures above $2-8^{\circ}C$, no significant differences were shown during the same period. After it reached 6, 8, 10, 12, and $20^{\circ}C$, the muscle had an accumulation of lactate, and a loss of ATP. There was no change in the lactate or ATP content during the feed restriction period at 2 and $4^{\circ}C$, although there were differences among the water temperature groups. These results clearly show that temperature can have an important influence on the of muscle of physiochemical characteristics of muscle during live fish transportation.