• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.747-748
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 추계학술대회 논문요약집
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• pp.14-14
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• 2003

• 대한기계학회논문집B
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• 제41권4호
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• pp.277-283
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• 2017

본 연구에서는 높이에 따른 점프 전략 변화를 이해하기 위해 반동을 이용한 수직 점프 시 상변화 시점에서의 지면반력 벡터가 높이에 따라 어떻게 변하는지 분석하였다; 반동과 추진 구간에서 유사한 힘 작용선을 갖는 수직 점프의 경우, 상변화 시점에서 반동의 이득을 나타내는 합력 벡터의 크기와 방향이 일정한 경향성을 가지고 높이에 따라 변화할 것이라 가정하였다. 9명의 청년군 모두는 정해진 5 종류의 높이를 총 5세트에 걸쳐 랜덤 방식으로 점프하였으며, 해당 높이를 유도하기 위해 지면으로부터 191 cm에서 221 cm 사이에 일정한 간격을 두고 마커를 배치하였다. 점프 높이가 증가함에 따라 반동 시 무게중심을 낮추고, 수평, 수직 방향의 힘을 증가시키는 것이 관찰되었는데, 이는 추진일을 증가시키기 위해 관절의 가용범위를 넓히고 초기 힘(또는 가속도) 이득을 늘리기 때문으로 생각된다.

• 한국운동역학회지
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• 제18권1호
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• pp.31-38
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• 2008

본 연구는 8주간의 전방십자인대 손상예방훈련이 농구 리바운드 점프 후 착지 시 지면반력에 미치는 영향을 규명하는 것이다. 본 연구에 참가한 연구 대상자는 $16{\sim}18$세 사이의 여자 농구선수 16명이다. 8주간의 전방십자인대 손상예방훈련을 수행할 실험집단 8명과 스포츠상해 예방훈련을 수행하지 않을 통제집단 8명을 무작위로 나눈 후 훈련 전후에 농구 리바운드 점프 후 착지 시 초기피크(%BW), 최대피크(%BW), 충격량(%BW.sec) 및 부하율 (N/sec)을 산출하였다. 본 연구 결과 농구 리바운드 점프 후 착지 시에 8주간의 전방십자인대 손상예방훈련을 받은 실험집단에서 초기피크 값이 감소하였다. 또한, 실험집단에서 지면반력의 충격량과 부하율이 유의하게 감소한 것으로 나타났다. 이는 8주간의 전방십자인대 손상예방 프로그램이 점프 동작에 필요한 하지의 근신경 조직에 유의한 긍정적 영향을 미쳐 효율적으로 착지한 것으로 판단된다.

• The Journal of Korean Physical Therapy
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• 제22권1호
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• pp.9-17
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• 2010

Purpose: The purpose of this study was to compare the effects of Tai-Chi exercise (TCE) and resistance exercise (RE) when used as part of a community-based exercise program on improvement of physical function in elderly women with knee arthritis. Methods: Forty-seven women with knee arthritis participated in this study. They were assigned to one of two groups: the TCE group (n=22) or the RE group (n=25). Tai-Chi exercise and resistance exercise sessions were held for 1 hour per session, twice per week, for 8 consecutive weeks. At pre-treatment and post-treatment, subjects were tested using the following measurements: one-legged stand test (sec), a functional reach test (cm), a test of the strength of the knee extensor and flexor muscles, determination of the pathway of center of foot pressure and vertical ground reaction force for stance phase at pre and post treatment time points. An independent t-test and a ${\chi}^2$ were used to determine the significance of differences between group means using SPSS 12.0. Results: After 8 weeks of participation in the exercise programs, there were significant improvements for both groups in joint pain, difficulty of performing activity, muscle strength of knee extensor and flexor. Also, vertical ground reaction force increased at the loading response phase for both groups. The RE group was significantly different from TC group on the eyes-closed one-legged stand test (sec). Conclusion: Tai-Chi exercise and resistance exercise programs improve physical functioning and reduce pain and locomotion difficulties.

• 한국운동역학회지
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• 제19권3호
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• pp.581-592
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• 2009

본 연구는 일반운동화와 스프링신발의 운동역학적 분석을 통해 일상적인 보행에서 스프링신발이 갖는 특성을 알아보기 위해 실시하였다. 이를 위해 정상족궁인 30-40대 여성 12명을 대상으로 2종류의 실험용 신발(스프링신발)과 비교용 신발(일반운동화)을 착용시킨 후 1.7m/s의 보행속도에서 지면반력기와 EMG, 적외선 카메라를 이용한 운동 역학적 분석을 실시하였다. 분석 결과 지면반력 분석에서는 제 1정점과 제 2정점에서 실험용신발이 일반운동화에 비해 큰 전후성분값을 나타냈다. 근전도분석에서는 대퇴직근의 활동이 스프링 신발을 신었을 때 증가하는 것으로 나타났다. 후족각에서 스프링 신발이 착지 시와 제1정점간에 일반화보다 크며 발목 관절을 중심으로 내측으로 회전하는 회내 운동을 적절하게 제어 하면서 이지 시에 후족 각의 감소에 영향을 미치는 것으로 나타났다. 따라서 스프링신발은 일반 신발에 비해 보행 시 무릎 신전근들의 근력 향상에는 도움을 줄 수 있을 것으로 판단된다.

• 대한의용생체공학회:의공학회지
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• 제22권6호
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• pp.543-550
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• 2001

본 연구에서는 하퇴 절단환자에서 고정형. 단축형, 다축형 인공족관절 장착시 지면반발력과 에너지 소비량을 측정하여 하퇴의지에 대한 생체역학적 평가를 하였다. 실험에는 각각 2명의 남성과 여성 하퇴 절단 환자가 3종류의 의지를 착용하고 참여하였으며. 3차원 보행분석은 7개의 기준점에 대하여 전체 입각기에 대한 지면 반발력의 체중에 대한 비율로 나타내었다. 하퇴의지 에너지 소비량은 피 실험자들이 각각 2km/h, 3km/h 그리고 가장 걷기 편한 속도로 런닝머신 위에서 보행하게 하면서 측정하였다 실험결과는 지면반발력에서 다축형 인공족관절 장착시 추진력과 후진력의 보행특성에 대하여 우위를 보이며, 고정형 인공족관절 장착시에는 보행균형과 무게중심의 이동에 대해 상대적인 우위를 보였다. 에너지 소비량은 2.3km/h 이상의 보행속도에서 단축형 인공족관절 장착시 다른 두 의지에 비해 적은량의 에너지 소비를 보였다.

• 한국운동역학회지
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• 제26권4호
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• pp.413-420
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• 2016

Objective: The purpose of this study was to analyze and compare different kinds of outdoor walking shoes in terms of muscle fatigue and ground reaction force on walking, and to provide foundational data for developing and choosing outdoor walking shoes that fit the users. Method: The study subjects were 30 healthy men. The experiment was conducted by using outdoor walking shoes with different inner and outer harnesses of the midsole, and shapes of the outsole. For data collection, electromyography was used to measure the muscle fatigue of the anterior tibial muscle and gastrocnemii, which contribute to the dorsiflexion and plantarflexion of the ankle joint, and the biceps muscle of the thigh and lateral great muscles, which contribute to the flexion and extension of the knee joint. A GRF measurement device was used to measure the X, Y, and Z axes. Results: In the type A outdoor walking shoes, regarding the hardness of the midsole, the inner part was soft, while the outer part was hard. The vertical ground reaction force was the lowest, which means least impact while walking and light load to the knees and ankles. The type C outdoor walking shoes were intended to provide a good feel in wearing the shoes. The tibialis anterior, biceps femoris, and gastrocnemii indicate low fatigue, which means that during a long-distance walk, it will minimize the fatigue in the muscles of the lower limbs. Conclusion: To sum up the study results, the different types of outdoor walking shoes indicate their unique characteristics in the biomechanical comparison and analysis. However, the difference was not statistically significant. Thus, a systematic and constant follow-up research should be conducted to cope with expanding market for outdoor walking shoes. Lastly, this study is expected to present foundational data and directions for developing outdoor walking shoes.

• Physical Therapy Rehabilitation Science
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• 제10권2호
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• pp.161-166
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• 2021

Objective: The purpose of this study was to quantitatively evaluate the Wii Balance Board (WBB)-based jump performance for the elderly and to confirm the difference in jump performance according to age. Design: Cross-sectional study. Methods: 40 young adults (aged 22.5±2.2 years) and 33 elderly (aged 75.1±5.2 years) without orthopedics disease participated in this study. Standing on the WBB then, with the signal "start," jump vertically to the maximum height at which you can jump, land on the force plate after jump and keep it standing on both feet. All subjects were required to practice the jump sufficiently before starting the measurement, each measuring three times, and the mean values were used. A one-minute break was provided between each trial. Evaluators waited within 1meter for every test to prepare for fall. Results: The vertical ground reaction force of elderly and young adults when jumping using WBB showed a significant difference (p<0.05) and demonstrated discriminant validity. Between two groups, there were significant differences in overall jump time (p<0.05), maximum value (p<0.05), minimum value (p<0.05), center of pressure (COP) pathlength (p<0.05), and flight time p<0.05). Conclusions: This study found that performing the vertical jump, the elderly showed longer jump time, lower vertical ground reaction force, COP pathlength and shorter flight phase than healthy young adults using WBB and demonstrated that as a measurement tool, WBB discriminated vertical jump performance between elderly and young adults.

• 대한통합의학회지
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• 제11권2호
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• pp.207-219
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• 2023

Purpose : This study was conducted to investigate the changes in trunk movement and ground reaction during sit to stand motion using visual feedback. Methods : Fifteen adults (average age: 23.53±1.77 years) participated in this study. An infrared reflective marker was attached to the body each participant for motion analysis, and the participants performed sit to stand motion while wearing a hat attached with a laser pointer, which provided visual feedback. First, the sit to stand action was repeated thrice without obtaining any visual feedback, followed by a three minute break. Next, the laser pointers attached to hats were irradiated on a whiteboard, located at a distance of 5 m in front of the chairs, on which the participants sat; a baseline was set, and the participants performed stand up movements three times under this condition. A visual feedback was provided to the participants to prevent the laser pointers from crossing the set baseline. During each stand-up movement, the position of the reflective marker attached to the subject's body was recorded in real time using an infrared camera for motion analysis. The trunk movement and ground reaction force were extracted through recorded data and analyzed according to the presence or absence of visual feedback. Results : The results indicated that in the presence of a visual feedback during the sit-to-stand movements, the range of motion of the trunk and hip joints decreased, whereas that of the knee and ankle joints increased in the sagittal plane. The rotation angle of the trunk in the horizontal plane decreased. The left and right movement speed of the center of pressure increased, the pressing force decreased, and the forward and backward movement speed of the trunk decreased. Conclusion : The results suggest that the efficiency and stability of the stand up movement of a body increase when a visual feedback is provided.