• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2317-2323
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• 2010

When the muscle is contracted by continuous and same, the force takes fatigue and stiffness. The aim of this study was to know how the fatigue and muscle stiffness change during an isometric contraction. Surface Electro myography(EMG) signal monitoring system and ultrasonic transducer set up the same muscle stem, subjects contract his right femoris muscle by submaximal isometric contraction(50% of MVC) until exhaustion. Before and after the test, muscle stiffness was measured and EMG was measured during the contraction. As time goes by, muscle fatigue was increased. and the stiffness was shown strongly after the contraction. These results show if the muscle becomes more and more fatigued, the circulation of muscle is delayed although the contraction doesn't happen. So muscle stiffness is increased.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.10a
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• pp.116-120
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• 1994

최근 항공우주 및 생산자동화 분야의 급격한 발달에 따라 정밀도와 효율성을 향상시키기 위해 저중량, 고강도 구조물이 요구된다. 그러나 경량화 추세로 인해 수반되는 구조물의 유연성 증가로 외력에 대한 구조응답의 진폭이 커지고 구조물의 피로 수명이 단축되어 매우 위험한 상황에 이를 수 있다. 이런 바람직하지 않은 진동현상을 제어하기 위해 여러 제어이론을 응용한 진동억제시스템의 연구가 활발하며, 신소재인 압전재료의 개발로 새로운 방향이 제시되고 있다. 압전재료는 유연한 구조물에 부착되어 압전재료의 수축, 팽창 운동에 의해 발생된 에너지를 부착된 구조물에서의 제어력으로 사용되어, 진동 혹은 자세 및 형상 제어에 활용되고 있다. 압전재료에 대한 연구로는 Crawley, de Luis3가 보의 표면 혹은 내부에 압전세라믹을 부착하여 액튜에이터로 사용하는 경우 집중모멘트를 가하는 역할을 함을 밝혔고, Hanagud, obal은 압전재료를 센서와 액튜에이터로 사용해 복합재료 보에 대한 최적 진동제어 알고리즘을 개발, 그 성능에 대한 효과를 조사하였고 임의의 위치에 부착된 센서 및 액튜에이터를 고려한 복합재료 보의 운동방정식을 유한요소법을 이용 유도하였으며 변위율 피드백(rate feedback)과 모달피드백(modal feedback) 제어기를 적용하여 진동제어 효과를 고찰하였다. 그리고 Tomas, James, Hubbard는 압전필름을 액튜에이터로 사용해 복합재료 보에 Liapunov 제어기와 변위율 피드백 제어기를 사용하여 능동감쇠기를 설계하였고, Lee, Chaing, Sullivan은 압전필름을 센서와 액튜에이터로 사용해 평판에 변위율 피드백 제어기를 적용한 능동감쇠기를 설계하고 실험적으로 수행하였다. Base가 백색잡음가진을 지속적으로 받을 때 보끝의 움직임이 최소가 되도록 제어하고자 연구를 수행 중인 바 그 결과로소 본 논문에서는 적용시켰고 F-P-K 방정식을 이용해 확률영역으로 변환하여 LQR 제어기와 pole allocation 제어기를 시스템에 적용시켜 우수한 특성을 갖음을 제어 시뮬레이션의 결과를 통해 입증하였다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.96-96
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• 2012

최근 주 5일제 근무 실행과 사회복지의 확산, 여가 선용에 대한 욕구와 더불어 건강증진에 대한 싸이클이 주목을 받고 있음. 싸이클웨어(Cycle Wear)에 요구되는 개발요소는 경기력 향상을 위한 기능적 요소와 패션성을 부여하는 심미적 요소로 크게 구분 가능하며 해외에서는 기능성과 패션성이 적절하게 조화를 이룬 제품을 계속 출시되고 있음. 본 연구에서는 운동 시 발생하는 열을 흡한속건 기능으로 효과적으로 발산하고 동절기에는 보온 기능을 갖는 세섬도 하이멀티 OY형 이형단면사 및 잠재권축사를 이용한 고신축 환편 및 경편물 개발하고, 극한환경에서도 고견뢰도를 유지할 수 있는 섬유의 염색법 및 기능성 발현 가공법의 적용, 내마모성과 필링이 우수한 아라미드+나일론 복합가공사 신축직물 제직 및 염색가공 공정 개발을 통해 기능성을 발현할 수 있는 싸이클 웨어 원단을 개발하였음. 또한 종래 Compression Wear에만 적용하던 테이핑 요법을 응용한 근력강화형 싸이클웨어 패턴과 디자인 개발을 통해 다양한 형태의 근력강화형 싸이클웨어를 개발하였으며, 무산소파워, 유산소파워, 젖산분석, EMG 분석 및 에너지 대사분석 등의 운동능력 성능평가를 통해 테이핑 요법이 적용된 싸이클웨어의 근력강화 효과를 확인하였음. 이와 같이 개발된 싸이클웨어는 무산소파워, 유산소파워, EMG 분석에서 각각 근력강화 효과를 보였으며, 피로물질인 젖산의 경우는 발생의 정도가 낮게 나타났음. 또한 여성에 비해 남성의 근력강화 효과가 크게 나타나는 경향을 보였음.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.2
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• pp.121-124
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• 2010

In athletes, repetitive low-energy impacts in plantar lesion lead often to tendinitis, stress fracture, or overuse syndrome. The major cause of heel pain in athletes is plantar fasciitis. And it is most often attributable to repetitive low energy impact, but the vast majority patients with heel pain achieve symptomatic relief with conservative treatment and return to full activities. Not commonly, Nerve entrapment may be occurred from repetitive low energy trauma in athletes, and is not as easily diagnosed. The authors observed a basketball player who complained of chronic heel pain that do not respond to conservative treatment, he had the lesions both plantar fasciitis and lateral plantar nerve entrapment. The authors described an unusual mechanism of entrapment of the lateral plantar nerve combined with a chronic plantar fasciitis in a basketball player and reported with review of literature.

• Journal of Korean Orthopaedic Sports Medicine
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• v.11 no.1
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• pp.8-16
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• 2012

With the increase of participation in the sport activities, there has been a commensurate rise in the number of sport injuries. A more commonly encountered injured region in the upper-extremity is the wrist. Sport injuries are often characterized as overuse and traumatic. Traumatic injuries include fractures, dislocations, and ligament tears often seen in contact or collision sports. Overuse injuries, represented damages by a level of repetitive microtrauma sufficient to overwhelm the tissues$^{\circ}{\O}$ ability to adapt, include inflammatory conditions such as De Quervain$^{\circ}{\O}s$ disease, extensor carpi ulnaris tendinitis, intersection syndrome. Also included is a traumatic problem such as stress fractures of the hook of the hamate, subluxation of the extensor carpi ulnaris tendon, chronic scapholunate instabilities, and degenerative triangular fibrocartilage tears. This review will focus on both overuse and traumatic injuries of the wrist in the athletes. A significant emphasis will be placed on the evaluation, pearls and pitfalls of conservative and operative treatments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.307-315
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• 2016

With advances in health care, the cancer survival rate has significantly increased. Even though cancer treatment has finished, cancer survivors may continuously suffer from physical and psychosocial problems. In order to investigate the problems cancer survivors have experienced, a comprehensive rehabilitation program must be developed. This study sought to determine the content and structure of rehabilitation programs for cancer survivors, analyze the effectiveness of such programs, and develop a basis for future comprehensive rehabilitation program development. Through this review, thirteen programs were selected and classified according to exercise, psychosocial, and integrated or comprehensive aspects. Exercise programs improve physical function, fatigue, and hormone-related cancer effects. Psychosocial programs improve quality of life, mood changes such as depression, anxiety, and post traumatic factors. Comprehensive programs improve both physical and psychosocial aspects.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.115-124
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• 2006

This study was conducted to investigate the running motion in the max-velocity phase(150-160m) and the fatigue phase(350-360m) during 400m sprint by performed elementary school athletes. Eighteen elementary school male athletes who achieved at least the 3rd place in the sprint at the Korea Gangwon-Do elementary school track and field meetings during 2004 and 2005 were selected as subjects. The running motions performed by the subjects were recorded using two 8mm high speed cameras at the nominal speed of 100 frames per second. The Direct Linear Transformation technique was adopted from the beginning of filming to the final stage of data extraction. KWON 3D motion analysis package program was used to compute the 3 Dimensional coordinates, smoothing factor in which lowpass filtering method was used and cutoff frequency was 6.0 Hz. The movement patterns during foot touchdown and takeoff for the running stride were related with the biomechanical consideration. Within the limitations of this study it is concluded: In order to increase running velocity, several conditions must be fullfilled at the instant of leg touchdown and takeoff during the fatigue phase(350-360m). First, the body C.O.G(Center of Gravity) height should be raised at the instant of leg touchdown and takeoff during the fatigue phase. Second, the foot contact time should be shortened and the takeoff distance should be increased at the foot takeoff during the fatigue phase. Third, the shank angular velocity with respect to a transverse axis through the center of gravity should be increased during the leg touchdown and takeoff in the fatigue phase. Forth, the active landing style described as clawing the ground with the sole of the foot should be performed during the leg touchdown and takeoff in the fatigue phase) phase. Fifth, In order to increase running velocity in the fatigue phase while taking a slightly greater leg knee angle and body lean angle within the range of the subject's running motion during the fatigue phase would result in greater flight distance.

• Journal of East-West Nursing Research
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• v.14 no.2
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• pp.16-23
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• 2008

Purpose: To examine the effects of a nursing intervention including moxibustion and theraband exercise on pain, fatigue, flexibility, and depression in aged patients with degenerative osteoarthritis. Methods: This study had a one group pretestposttest design. Thirty people over 60 yr-of-age with degenerative osteoarthritis were recruited from a community health center from November 1, 2005 to June 14, 2006. The 6 week treatment intervention included twice weekly 60 min sessions of of theraband exercise (30 min) and moxibution (30 min). Data was analyzed by SPSS Ver. 12.0. Results: Intervention was associated with significant decreases in pain (t=8.28, p<.001) and fatigue (t=5.19, p<.001), and significant increases in knee flexibility (t=-3.54, p=.001), dorsal flexibility (t=-9.05, p<.001), and plantar flexibility (t=-4.09, p<.001). Depression was significantly decreased after intervention (t=-4.09, p<.001). Conclusions: Moxibustion and theraband exercise should be utilized as an effective nursing intervention for the aged with degenerative oateoarthritis.

• Journal of muscle and joint health
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• v.17 no.1
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• pp.47-57
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• 2010

Purpose: The purpose of the study was to identify the effects of a 9-week self-help management aquatic exercise program on pain, flexibility, balance, fatigue and self-efficacy in the patients with osteoarthritis living in the suburban area. Methods: Utilizing a quasi-experimental design, 43 osteoarthritis patients consisted of the experimental group (n=20) and the control group (n=23). Due to the busy schedule of the patients working in the farm, the program was provided for 9 weeks instead of 12 week program under the guidance of professional advice. The questionnaires and physical measurements were used to measure the outcome variables before and after the program. Data were analyzed with the SPSS WIN using descriptive statistics, t-test and ANCOVA. Results: The age was significantly different between the groups. After controlling for the age, pain and fatigue in the experimental group decreased significantly more than the control group. Flexibility, balance and self-efficacy in the experimental group improved significantly more than the control group. Conclusion: This 9-week program could be an effective nursing intervention to be used especially for osteoarthritis patients in the suburban area during the leisure seasons of the farmers to improve their arthritic symptoms and self-efficacy.

• Korean Journal of Applied Biomechanics
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• v.23 no.4
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• pp.335-345
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• 2013

The purpose of this study was to investigate the effects of foot type and ankle joint fatigue levels on the trajectories of center of pressure and center of mass during a single-leg stance. The study subjects included 24 healthy women (normal foot group, n=10; pronated foot group, n=14). Ankle joint muscle fatigue was induced by using an isokinetic dynamometer, where the fatigue levels were measured on plantar flexion and dorsiflexion at angular velocities of $30^{\circ}/s$ at 50% and 30% of the peak torque of ankle plantar flexion. Following assessments in the anteroposterior direction according to the level of fatigue, the pronated foot group showed decreased single-leg stance ability at 50% and 30% of the fatigue level. Moreover, the normal foot group showed better single-leg stance ability than the pronated foot group at 30% of the fatigue level. Following assessments in the mediolateral direction, we noted that the single-leg stance ability did not differ significantly according to the levels of fatigue or foot type. In conclusion, ankle plantar flexion at 50% and 30% of the peak torque reduced the ability of the pronated foot group to achieve a single leg stance in the anteroposterior direction. Moreover, the normal foot group showed better single-leg stance ability than the pronated foot group.