• 한국운동역학회지
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• 제25권1호
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• pp.85-94
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• 2015

Purpose : The purpose of this study was to investigate the influence on the ground reaction force parameters according to wearing positions of backpack for during stair ascending and descending. Methods : Participants selected as subject were consisted of young female(n=10) and performed stairs walks(ascending and descending) with 2 types of wearing position(front of trunk[FT], rear of trunk[RT]). Passive(Fz 1) and active(Fz 2) forces of the vertical GRF were determined from time function and frequency domain. Also shear forces(Fx, Fy 1, Fy 2), dynamic postural stability index(MLSI, APSI, VSI, DPSI), loading rate and center of pressure (${\Delta}COPx$, ${\Delta}COPy$, COP area) were calculated from time function and frequency domain. Results : Fx, Fy 1, Fy 2, and Fz 1 in GRF didn't show significant differences statistically according to the wearing positions of backpack(p>.05), but stair descending showed higher forces than that of stair ascending. Particularly, Fz 2 of stair ascending showed higher forces than that of stair descending(p<.001), RT types showed higher than that of FT types(p<.05). MLSI, APSI, VSI, and DPSI of stair descending showed the increased stability index than that of stair ascending(p<.05), MLSI of RT types showed the decreased stability index than that of FT types(p<.05). Loading rate didn't show significant differences statistically according to the wearing positions of backpack(p>.05), but stair descending showed higher loading rate than that of stair ascending(p<.001). Also, ${\Delta}COPx$ in stair descending showed the increased movement than that of stair ascending(p<.05). Conclusions : A backpack of 10 kg(10 kg(ratio of body weights $17.61{\pm}1.17%$) showed significantly change GRF parameters according to wearing positions during stair ascending and descending. If possible, we suggest that the dynamic stability, in case of stairs walking with a smaller weights can be further improved.

• 한국운동역학회지
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• 제18권1호
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• pp.169-178
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• 2008

본 연구는 계단 보행 중 연속적인 두 스텝의 3차원적 지면반력 파라미터를 제공하고, 계단의 너비에 따른 지면 반력 파라미터의 차이 및 비대칭성과 일관성을 규명하는데 있다. 10명의 성인 대상자가 본 실험에 참여하였으며, 각 10번의 평지, 상향 및 하향보행을 3가지의 다른 너비의 계단에서 실시하였다. 본 연구를 수행한 결과 다음과 같은 결론을 얻었다. 첫째, 계단의 너비는 대부분의 지면반력 파라미터들의 패턴이나 일관성, 비대칭지수에 영향을 미치지 않았다. 둘째, 평지 보행과 계단보행은 지면반력 파라미터의 패턴에서 큰 차이를 보였다. 평지보행과 상향보행은 Fz1, Fz2, 그리고 Fz3로 구성되는 "M" 형태를 보인 반면에 하향보행에서는 Fz2가 거의 없고 큰 Fz1과 작은 Fz3로 구성된 패턴을 보였다. 또한 계단 보행은 평지보행과 매우 다른 전 후 지면반력 패턴을 보였다. 즉 상향보행은 Fy1이 존재하지 않는 패턴을, 하향보행은 Fy2가 존재하나 매우 작은 크기를 보였다. 셋째, 계단보행의 수직 지면반력 파라미터들은 적용가능한 일관성 지수 및 비대칭 지수를 나타내었다.

• 한국운동역학회지
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• 제18권4호
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• pp.161-169
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• 2008

이 연구는 성인 남성을 대상으로 계단 너비에 따른 계단 보행의 지지국면 시 하지분절의 역학적 변인을 정량적으로 분석하여, 보다 효과적인 계단의 너비를 제시하고자 실시하였으며, 이를 위해 20대의 남자 대학생 10명이 참여하였다. 계단의 높이는 18cm, 최소폭은 90cm로 동일하나 디딤면의 너비가 각각 26cm, 31cm, 36cm인 세 개의 계단을 사용 하였다. 이때 사용된 계단의 세 번째 디딤면에 지면반력기를 설치하여 지지구간의 하지관절 모멘트를 분석한바 다음과 같은 결론을 얻었다. 상향계단보행에서 발목관절의 굴곡/신전 모멘트변화를 분석한 결과 계단의 너비가 증가 할수록 pull-up 단계의 peak 모멘트가 감소하였으며(p<.05), 무릎관절에서는 굴곡/신전 모멘트를 분석한 결과 계단의 너비가 증가할수록 무릎에 작용하는 신전모멘트가 중지지기에 증가하는 것으로 나타났다(p<.05). 그러나 고관절에서 차이가 없는 것으로 나타났다. 그리고 하향계단보행에서 발목관절의 굴곡/신전 모멘트를 분석한 결과 계단의 너비가 증가할수록 지지기 동안 저측굴곡과 배측굴곡의 차이가 확연히 나타나는 것으로 나타났으며(p<.05), 무릎관절과 고관절에서는 굴곡/신전 모멘트를 분석한 결과 계단의 너비에 따라 신전 모멘트의 차이가 크지 않은 것으로 나타났다.

• 한국운동역학회지
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• 제25권3호
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• pp.323-333
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• 2015

Objective : The purpose of this study was to investigate the changes of gait patterns and muscle activations with increased loads during stair walking. Also, it can be used as descriptive data about continuous stair walking in a real life setting. Method : Twelve sedentary young male adults(Age: $27.0{\pm}1.8yrs$, Weight: $65.8{\pm}9.9kg$) without any lower extremity injuries participated in this study. Participants performed stair walking up 7 floors and their ascending and descending motion on each floor was analyzed. A wireless electromyography(EMG) were attached on the Rectus Femoris(RF), Biceps Femoris(BF), Gastrocnemius(GN), Tibialis Anterior(TA) muscle to calculate integrated EMG(iEMG), median frequency(MDF) and co-contraction index(CI). Chest and left heel accelerometer signal were recorded by wireless accelerometer and those were used to calculate approximate entropy(ApEn) for analyzing gait pattern. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was LSD. Results : During ascending stairs, there were a statistically significant difference in Walking time between 1-2nd and other floors(p=.000), GN iEMG between 2-3th and 6-7th(p=.043) floor, TA MDF between 1-2nd and 5-6th(p=.030), 6-7th(p=.015) floor and TA/GN CI between 2-3th and 6-7th(p=.038) floor and ApEn between 1-2nd and 6-7th(x: p=.003, y: p=.005, z: p=.006) floor. During descending stairs, there were a statistically significant difference in TA iEMG between the 6-5th and 3-2nd(p=.026) floor, and for the ApEn between the 1-2nd and 6-7th(x: p=.037, y: p=.000, z: p=.000) floor. Conclusion : Subjects showed more regular pattern and muscle activation response caused by regularity during ascending stairs. Regularity during the first part of stair-descending could be a sign of adaptation; however, complexity during the second part could be a strategy to decrease the impact.

• 한국운동역학회지
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• 제25권3호
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• pp.241-248
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• 2015

Objective : The purpose of this study was to investigate the theta on the components of ground reaction force according to the ground conditions during gait. Method : Six healthy women(mean age: 22 yrs, mean height: $166.14{\pm}2.51cm$, mean body weights: $56.61{\pm}4.58kg$) participated in this study. The medial-lateral GRF(Fx 1), anterior-posterior GRF(Fy 1, Fy 2), vertical GRF(Fz 1, Fz 2, Fz 3), and impact loading rate were determined from time function and frequency domain. Also, GRF theta were time function and forces. Results : Fx 1, Fy 1 and Fy 2 of stair descending showed significant statistically higher forces than that of level walking, and ascending. Fz 1 of stairs descending showed significant statistically higher forces than that of level walking and stairs ascending(theta $88.62^{\circ}$). Also, Fz 2 of level walking showed significant statistically higher forces than that of stairs ascending and descending(theta $65.78^{\circ}$). Fz 3 of stairs ascending showed significant statistically higher forces than that of level walking and stairs descending($65.26^{\circ}$). Impact loading rate of stairs descending showed significant statistically higher forces than that of level and ascending walking. The GRF showed similar correlation with GRF theta(r=.603) according to the ground conditions during gait. Conclusion : These results suggest that the GRF theta can be used in conjunction with a gait characteristics, prediction of loading rate and dynamic stability.

• 재활복지공학회논문지
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• 제6권2호
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• pp.15-22
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• 2012

외골격 보행보조로봇은 로봇 시스템을 인체에 직접 착용하는 형태이므로 기구적인 측면에서는 인체 근골격 구조에 최적화된 메커니즘으로 구성되어야 하며, 제어적인 측면에서는 근골격계의 손상을 일으킬 수 있는 로봇의 부적합한 거동을 예방할 수 있는 안전장치를 갖추어야 한다. 외골격 보행보조로봇을 개발하기 위해서는 보행이나 근골격계의 거동특성에 대한 이해 및 분석이 필요하다. 본 연구에서는 최적화된 로봇시스템 설계를 위하여 구동장치의 관절력과 동력 용량을 예측하였으며 몇 가지 보행동작에 대한.관절거동특성을 파악할 수 있는 자료를 획득하였다. 평지보행을 제외한 나타나는 주요한 동작으로는 계단오르고 내리기, 안기, 서기, 경사면 걷기 등이 있다. 본 연구에서는 경사면 걷기를 제외한 모든 동작에 대한 동작 실험을 수행하고 분석하였다.

• 전자공학회논문지
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• 제52권3호
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• pp.181-189
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• 2015

동력의족은 하지 절단 환자나 다리근력이 부족한 사람들의 보행 보조를 위해 사용된다. 동력의족의 자연스러운 구동을 위해 선 보행단계가 잘 분류되어야 한다. 물리센서를 이용하여 보행단계를 분류하는 기존 연구는 동력의족이 사전에 훈련된 보행속도로만 재현되는 단점이 있다. 따라서 본 논문에서는 물리센서를 사용하지 않고, 근전도 신호만을 이용하여 오르막, 내리막 계단보행을 각각 4단계로 분류하는 방법을 제안한다. 근전도 신호를 RMS, VAR, MAV, SSC, ZC, WAMP 특징으로 산출하여 LDA(Linear Discriminant Analysis) 분류기를 통해 보행단계를 인식한다. 훈련 단계에서는 AHRS센서를 이용하여 무릎각도 변화에 따른 보행단계 범위를 생성한다. 실험 결과, 선행 연구의 경우 오르막 보행에서 평균 58.5%, 내리막 보행에서 35.3%의 정확도를 보인다. 반면, 제안하는 방법은 오르막 보행에서 평균 85.6%, 내리막 보행에서 69.5%의 인식률을 보인다. 또한, 본 연구를 통해 개별 근육 별 보행단계 평균 인식률을 분석하였다.

• 한국정밀공학회지
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• 제23권4호
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• pp.75-82
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• 2006

In this paper, we propose an optimal trajectory for biped robots to move up-and-down stairs using a genetic algorithm and a computed-torque control for biped robots to be dynamically stable. First, a Real-Coded Genetic Algorithm (RCGA) which of operators are composed of reproduction, crossover and mutation is used to minimize the total energy. Constraints are divided into equalities and inequalities: Equality constraints consist of a position condition at the start and end of a step period and repeatability conditions related to each joint angle and angular velocity. Inequality constraints include collision avoidance conditions of a swing leg at the face and edge of a stair, knee joint conditions with respect to the avoidance of the kinematic singularity, and the zero moment point condition with respect to the stability into the going direction. In order to approximate a gait, each joint angle trajectory is defined as a 4-th order polynomial of which coefficients are chromosomes. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot that consists of seven links in the sagittal plane. The trajectory is more efficient than that generated by the modified GCIPM. And various trajectories generated by the proposed GA method are analyzed in a viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.84-85
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• 1998

This study was conducted to characterize the gait of a person climbing or descending the stairs. Using our motion analysis system (Vicon 370), gait patterns of ten healthy females (18.8 - 19.6 yrs. old) were measured 1) when a subject tip-toed the stairs, 2) when a subject climbs the stairs with the whole foot, and 3) when a subject went down the stair, respectively. The results of each cases were compared with the data for the level walking collected from 21 healthy females in the previous studies. The stairway gait data can be used as a useful reference in the design of artificial limbs for the lower-limb amputee.

• 한국응급구조학회지
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• 제11권1호
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• pp.11-25
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• 2007

Objective: The purpose of this study was to investigate the effects of combined exercise on the change of postural control, functional status in patients with osteoarthritis of the knee. Methods : The subjects were consisted of 24 women patients fifties and sixties with knee osteoarthritis. Each group had a exercise for 30 minutes per day and three times a week during 8 weeks period. Was used to measure muscular function(60, $180^{\circ}/sec$), postural control. functional capacity(15 M walking test, Rising form a chair test, stair climbing and descending test) and the functional state of a joint(WOMAC). Results: This study results in following 1. In case of muscular function have significantly increased in both groups. 2. There was no significant difference in the postural control of the bilateral between two groups. However, the postural control of a isokinetic exercise program group showed a significant difference in the bilateral side(overall, $M{\cdot}L$ stability index). Especially, the change of postural control in the isokinetic plus postural control exercise program group decreased more significantly in the bilateral(overall, $A{\cdot}P$ stability index). 3 It was significantly decreased in climbing and descending the stairs, and rising from the chair, although functional capacity decreased in lam walking in both groups. 4. The functional state of a joint(WOMAC) showed a significant decrease in both groups. Conclusion : In order to improve the functional status and postural control of patients with osteoarthritis of the knee, performing exercise programming of isokinetic plus balance will be more effective than the exercise program composed of only the isokinetic exercise program.