• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.187-194
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• 2007

The purpose of this study is to determine the characteristics of ground reaction force(GRF) in golf swing for various slopes of flat lie and uphill lies of 5 and 10 degrees. Five right-handed professional golfers were selected for the experiment and the 7 iron club was used. We used four forceplates to measure GRF and synchronized with the three-dimensional motion analysis system. Results showed that slope did not affect the total time for golf swing, but the time until the impact had a tendency to slightly increase for the uphill lie(p<0.05). The medial-lateral GRF of the right foot increased toward the medial direction during back swing, but less increases were found with the angle of uphill lie(p<0.05). The GRF of the left foot increased rapidly toward the medial direction at the uncocking and the impact during down swing, but decreased with the increase in the angle of uphill lie(p<0.05). The anterior-posterior GRF of both feet showed almost the same for different slopes. With the slopes, the vertical GRF of the right foot increased, but the vertical GRF of left foot decreased(p<0.05). Uphill lies would have negative effect to provide the angular momentum during back swing, restricting pelvic and trunk rotations, and to provide the precise timing and strong power during down swing, limiting movements of body's center of mass. The present study could provide valuable information to quantitatively analyze the dynamics of golf swing. Further study would be required to understand detailed mechanism in golf swing under different conditions.

• 한국융합학회논문지
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• 제9권8호
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• pp.301-309
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• 2018

본 연구의 목적은 여성선수의 신경인지능력이 양발 착지 시 비접촉성 전방십자인대 손상의 위험요인과 어떠한 관계가 있는지 규명하는 것이다. 여성선수 32명을 대상으로 신경인지검사와 양발 착지에 대한 동작분석을 실시하였다. 전산화된 신경인지 검사의 원점수와 동작분석을 통해 산출된 3차원 관절각, 모멘트, 파워, 수직지면반력, 부하율, 지지시간의 상관관계 분석을 위해 피어슨의 정률상관분석을 실시하였다. 연구결과 신경인지 점수가 높을수록 착지 시 자세유지를 위한 전략을 사용하는 것이 관찰되었다. 따라서 신경인지 검사는 잠재적인 전방십자인대 손상의 위험인자를 검출하기 위한 스크리닝 방법으로 사용 될 수 있을 것으로 생각된다.

• 대한의용생체공학회:의공학회지
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• 제32권2호
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• pp.165-176
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• 2011

The femoral nerve innervates the quadriceps muscles and its dermatome supplies anteromedial thigh and medial foot. Paralysis of the quadriceps muscles due to the injury of the femoral nerve results in disability of the knee joint extension and loss of sensory of the thigh. A child could walk independently even though he had injured his femoral nerve severely due to the penetrating wound in the medial thigh. We measured and analyzed his gait performance in order to find the mechanisms that enabled him to walk independently. The child was eleven-year-old boy and he could not extend his knee voluntarily at all during a month after the injury. His gait analysis was performed five times (GA1~GA5) for sixteen months. His temporal-spatial parameters were not significantly different after the GA2 or GA3 test, and significant asymmetry was not observed except the single support time in GA1 results. The Lower limb joint angles in affected side had large differences in GA1 compared with the normal normative patterns. There were little knee joint flexion and extension motion during the stance phase in GA1 The maximum ankle plantar/dorsi flexion angles and the maximum knee extension angles were different from the normal values in the sound side. Asymmetries of the joint angles were analyzed by using the peak values. Significant asymmetries were found in GA1with seven parameters (ankle: peak planter flexion angle in stance phase, range of motion; ROM, knee: peak flexion angles during both stance and swing phase, ROM, hip: peak extension angle, ROM) while only two parameters (maximum hip extension angle and ROM of hip joint) had significant differences in GA5. The mid-stance valleys were not observed in both right and left sides of vertical ground reaction force (GRF) in the GA1, GA2. The loading response peak was far larger than the terminal stance peak of vertical ground reaction curve in the affected side of the GA3, GA4, GA5. The measured joint moment curves of the GA1, GA2, GA3 had large deviations and all of kinetic results had differences with the normal patterns. EMG signals described an absence of the rectus femoris muscle activity in the GA1 and GA2 (affected side). The EMG signals were detected in the GA3 and GA4 but their patterns were not normal yet, then their normal patterns were detected in the GA5. Through these following gait analysis of a child who had selective injuries on the knee extensor muscles, we could verify the actual functions of the knee extensor muscles during gait, and we also could observe his recovery and asymmetry with quantitative data during his rehabilitation.

• Geomechanics and Engineering
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• 제29권3호
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• pp.207-218
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• 2022

In submerged floating tunnels (SFTs), a next-generation maritime transportation infrastructure, the tunnel module floats in water due to buoyancy. For the effective and economical use of SFTs, connection with the ground is inevitable, but the stability of the shore connection is weak due to stress concentration caused by the displacement difference between the subsea bored tunnel and the SFT. The use of an elastic joint has been proposed as a solution to solve the stability problem, but it changes the dynamic characteristics of the SFT, such as natural frequency and mode shape. In this study, the finite element method (FEM) was used to simulate the elastic joints in shore connections, assuming that the ground is a hard rock without displacement. In addition, a small-scale model test was performed for FEM model validation. A parametric study was conducted on the resonance behavior such as the natural frequency change and velocity, stress, and reaction force distribution change of the SFT system by varying the joint stiffness under loading conditions of various frequencies and directions. The results indicated that the natural frequency of the SFT system increased as the stiffness of the elastic joint increased, and the risk of resonance was the highest in the low-frequency environment. Moreover, stress concentration was observed in both the SFT and the shore connection when resonance occurred in the vertical mode. The results of this study are expected to be utilized in the process of quantitative research such as designing elastic joints to prevent resonance in the future.

• 한국운동역학회지
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• 제26권2호
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• pp.161-166
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• 2016

Objective: The purpose of this study was to determine the knee and ankle joint kinematics and kinetics by comparing downhill walking with valley-shape combined slope walking. Method: Eighteen healthy men participated in this study. A three-dimensional motion capture system equipped with eight infrared cameras and a synchronized force plate, which was embedded in the sloped walkway, was used. Obtained kinematic and kinetic parameters were compared using paired two-tailed Student's t-tests at a significance level of 0.05. Results: The knee flexion angle after the mid-stance phase, the mean peak knee flexion angle in the early swing phase, and the ankle mean peak dorsiflexion angle were greater during downhill walking compared with valley-shape combined slope walking (p < 0.001). Both the mean peak vertical ground reaction force (GRF) in the early stance phase and late stance phase during downhill walking were smaller than those values during valley-shape combined slope walking. (p = 0.007 and p < 0.001, respectively). The mean peak anterior GRF, appearing right after toe-off during downhill walking, was also smaller than that of valley-shape combined slope walking (p = 0.002). The mean peak knee extension moment and ankle plantar flexion moment in late stance phase during downhill walking were significantly smaller than those of valley-shape combined slope walking (p = 0.002 and p = 0.015, respectively). Conclusion: These results suggest that gait strategy was modified during valley-shape combined slope walking when compared with continuous downhill walking in order to gain the propulsion for lifting the body up the incline for foot clearance.

• 한국운동역학회지
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• 제24권1호
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• pp.51-57
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• 2014

The purpose of this study was to compare and analyze kinetic variables of lower limbs according to types of ankle taping in drop landing. For this, targeting seven male basketball players (average age: $20.8{\pm}0.74yrs$, average height: $187.4{\pm}3.92cm$, average weight: $79.8{\pm}7.62kg$) with no instability of ankle joints, the drop landing motion was conducted according to three types of inelastic taping (C-type), elastic taping (K-type), and no treatment (N-taping). Based on the result, the next conclusion was reached. First, the effect of taping for the players with stable ankles was minimal and the high load on ankle joints offset the fixing effect of inelastic taping. Thus the inelastic taping for the players with stable ankles did not have an effect on the control of dorsal flexion during one-foot landing. Second, increasing angular velocity by increasing the movable range of knee joints disperses impact forces, yet inelastic taping restricted the range of knee joint motion and at the same time increased angular velocity, adding to a negative effect on knee joints. Third, inelastic taping induced inefficient motion of Lower limbs and unstable impact force control of ankle joints at the moment of landing and produced maximum vertical ground reaction force, which led to an increase of load. Therefore, inelastic ankle taping of players whose jump actions occur very often should be reconsidered. Also, it is thought that this study has a great meaning in proving the problem of inelastic taping related to knee pain with unknown causes.

• 대한물리의학회지
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• 제8권1호
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• pp.49-58
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• 2013

PURPOSE: The purpose of this study was to determine if auditory cues velocity has a greater effect on the gait pattern of patients with Parkinson's disease (PD) than the cues applied individually. METHODS: The subjects were 15 elderly patients diagnosed with PD, 15 healthy elderly persons. Patients were measured of three conditions performed in random order: slow, general, fast. The auditory cue velocity consisted of a metronome beat ${\pm}20%$ than the subject's general gait speed. Using a motion analysis and a force platform measurement system, changes in spatiotemporal variables, kinetic and kinematic variables were compared to gait analysis. RESULTS: Comparison between the auditory cues velocity, there was a significant difference in the spatiotemporal variables with regard to the cadence, stride length, support time, step length, double support time (p<.05). Comparison between the auditory cues velocity, there was a significant increase general and fast velocity gait than slow velocity gait in the maximum flexion in swing phase of knee joint (p<.05). There appears to be the aspect of an increasing ground reaction force (GRF) on the first peak in the vertical axis (p<.05). CONCLUSION: Auditory cues velocity improved of spatio-temporal factors, kinematic and kinetic factors depending on the velocity of the faster. Therefore at the rehabilitation training of PD patients auditory cues velocity would be used for recovery and gait reeducation, may arise through the patients functional ability.

• 융합정보논문지
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• 제10권4호
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• pp.160-167
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• 2020

본 연구는 달리기 시 속도와 경사변화가 하지관절의 생체역학적 요인에 미치는 영향을 보고자 한다. 이를 위해 20대 성인남성 15명이 트레드밀에서 2.7, 3.3 m/s와 -9°, -6°, 0°, 6°, 9°로 달리기를 실시하였고, 속도와 경사 변화에 따른 주행특성(보장, 보빈도), 생체역학적 변인(발목, 무릎, 엉덩관절의 가동범위, 모멘트, 관절파워), 지면반력(수직지면반력, 부하율, 제동력, 추진력)을 측정하였다. 연구결과, 주행특성은 오르막 달리기(UR)가 내리막 달리기(DR)에 비해 크게 나타났다(p<.05). 하지관절의 가동범위와 수직지면반력은 UR에서 크게 나타났고(p<.05), 하지관절의 모멘트와 제동력, 추진력, 부하율은 DR에서 크게 나타났다(p<.05). 관절파워는 발목관절은 DR에서 크고, 엉덩관절에서는 UR이 크게 나타났다(p<.05). 이러한 결과로부터 3.3m/s의 속도로 DR을 달리는 경우에서 발목관절 부상의 영향이 클 것으로 예상된다.

• 한국전문물리치료학회지
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• 제7권4호
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• pp.39-46
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• 2000

본 연구는 강직성 편측 뇌성마비 환자의 보행 기시(gait initiation)의 특성을 파악하고, 동적 단하지 보조기(dynamic ankle foot orthosis : DAFO)가 이런 환자들의 보행 기시에 미치는 영향을 알아보기 위하여 실시하였다. 연구대상자는 19세 선천성 강직성 우측 뇌성마비를 가진 여자 대학생이었다. 연구대상자는 4개의 다른 보행 기시 조건에서 각 조건당 7회의 보행 기시를 하였는데, 각각의 보행 기시 조건은: 1) 보조기 없이 좌측 하지로 보행 기시; 2) 우측 하지 보조기 착용 상태에서 좌측하지로 보행 기시; 3) 보조기 없이 우측 하지로 보행 기시; 4) 우측 하지 보조기 착용 상태에서 우측 하지로 보행 기시였다. 두개의 힘 판(force plate) 위에서 본인이 선택한 가장 편안한 방법과 속도로 2 m를 걷도록 하였다. 연구대상자가 보행 기시를 하는 동안 양쪽 가자미근과 앞정강근에 부착된 4개의 표면 전극으로부터 근 전도 신호와 보행 기시를 하는 연구 대상의 양 발 아래 놓인 두개의 힘 판의 자료를 분석하여 체중(body weight : BW)으로 정량화 하였다. 실험결과는 각 조건마다 7회 실시된 측정값들의 평균을 이용하였다. 본 사전연구의 결과는 다음과 같다. 1. 보행 기시 전 양다리로 선 상태에서 환측보다 건측으로 많은 체중지지를 하였으나(환측 42.57%BW, 건측 58.03%BW) 보조기의 착용이 환측으로의 체중지지를 향상시켰다(환측 44.46%BW, 건측 55.54%BW). 2. 보행 기시 중 가자미근과 앞정강근의 동시수축(coactivation)이 계속되었는데 이러한 양상은 보조기의 착용 유무에 따라 크게 달라지지 않았다. 3. 힘 판에서 들어온 지면 반발력(ground reaction force)의 수직 분력(vertical element, Fz)과 전후 분력(anterior-posterior element, Fx)을 분석한 결과, 건측 다리로 보행 기시를 할 때 보조기 착용은 가속을 촉진시켜 역학적으로 유리하였다. 이상의 연구 결과는 보조기의 착용이 건측 다리로 보행 기시를 할 때 미치는 신경학적, 역학적 장점들에 대한 구체적 연구의 필요성 및 근거를 제시하고, 환자들의 보행훈련 접근에 보다 효율적인 보행방법을 소개하는데 이용될 수 있다.

• 한국운동역학회지
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• 제19권3호
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• pp.457-466
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• 2009

본 연구는 현대무용 아라베스크 동작 시 팔의 사용 유.무에 따라 아라베스크 동작 바로직후의 턴으로 이어지는 동작에 영향을 미치는 운동역학적 변인을 분석하여 무용 동작에 대한 과학적 근거를 마련하고자 하는 연구의 목적이 있다. 상지를 이용하지 않은 아라베스크 턴 동작이 상지를 이용한 아라베스크 턴 동작 보다 머리의 회전력과 몸통의 회전력을 더 사용 하였고, 오른쪽 어깨를 이용한 회전력을 얻었다. 상지를 이용한 아라베스크 턴 동작은 왼쪽의 고관절 범위와 왼쪽 발끝의 위치변화가 수직축으로 크게 상승되어 있고, 상지를 이용하지 않는 아라베스크 턴 동작은 발끝의 위치가 이벤트별 아래로 떨어졌다. 신체중심 변위에서는 상지를 이용한 아라베스크 턴 동작이 회전하는 축으로 더 크게 이동하였고, 상지를 이용하지 않은 아라베스크 턴 동작의 신체중심이 낮게 위치하였다. 또한 최대 수직지면반력의 결과 상지를 이용한 아라베스크 턴 동작이 상지를 이용하지 않은 동작보다 낮은 값으로 나타나, 상지를 이용하지 않은 아라베스크 턴 동작이 상지를 이용한 동작보다 하지의 체중부하를 더 사용한다는 것으로 나타났다.