• 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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• 제25권2호
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• pp.191-198
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• 2015

Objective : The purpose of this study was to conduct biomechanical analysis of varying backpack loads on the lower limb movements during downhill walking over $-20^{\circ}$ ramp. Method : Thirteen male university students (age: $23.5{\pm}2.1yrs$, height: $175.7{\pm}4.6cm$, weight: $651.9{\pm}55.5N$) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked over $20^{\circ}$ ramp with four different backpack weights (0%, 10%, 20% and 30% of body weight) in random order at a speed of $1.0{\pm}0.1m/s$. Five digital camcorders and two force plates were used to obtain 3-d data and kinetics of the lower extremity. For each trial being analyzed, five critical instants were identified from the video recordings. Ground reaction force, loading rate, decay rate, and resultant joint moment of the ankle and the knee were determined by the inverse dynamics analysis. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among four different backpack weight conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results : The results of this study showed that the medio-lateral GRFs at RHC in 20% and 30% body weight were significantly greater than the corresponding value in 0% of body weight. A consistent increase in the vertical GRFs as backpack loads increased was observed. The valgus joint movement of the knee at RTO in 30% body weight was significantly greater than the corresponding values in 0% and 10% body weight. The increased valgus moment of 30% body weight observed in this phase was associated with decelerating and stabilizing effects on the knee joint. The results also showed that the extension and valgus joint moments of the knee were systematically affected by the backpack load during downhill walking. Conclusion : Since downhill walking while carrying heavy external loads in a backpack may lead to excessive knee joint moment, damage can occur to the joint structures such as joint capsule and ligaments. Therefore, excessive repetitions of downhill walking should be avoided if the lower extremity is subjected to abnormally high levels of load over an extended period of time.

• 한국전문물리치료학회지
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• 제26권2호
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• pp.1-7
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• 2019

Background: In previous studies, changes in postural alignment were found when the slope was changed during walking. Downhill walking straightens the trunk by shifting the line of gravity backward. Objects: This study investigated the effect of the downhill treadmill walking exercise (DTWE) on thoracic angle and thoracic erector spinae (TES) activation in subjects with thoracic kyphosis. Methods: A total of 20 subjects with thoracic kyphosis were recruited for this study. All the subjects performed the DTWE for 30 minutes. A surface EMG and 3D motion capture system were used to measure TES activation and thoracic angle before and after the DTWE. Paired t-tests were used to confirm the effect of the DTWE (p<.05). Results: Both the thoracic angle and TES activation had significantly increased after the DTWE compared to the baseline (p<.05). An increase in the thoracic angle indicates a decrease in kyphosis. Conclusion: The DTWE is effective for thoracic kyphosis patients as it decreases their kyphotic posture and increases the TES activation. Future longitudinal studies are required to investigate the long-term effects of the DTWE.

• 대한기계학회논문집B
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• 제41권3호
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• pp.153-160
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• 2017

보행 분석은 다양한 지형에서 수행되고 있으나 지형이 변화되는 시점에서의 보행 분석 연구는 보고된 바 없다. 본 연구의 목적은 삼각경사 보행 시 지형이 변화되는 시점에서 발목 및 무릎 관절의 운동학과 운동역학을 평지 보행과 비교 분석하는 것이다. 3차원 동작분석 시스템과 지면 반력기를 사용하여 성인 남성 18명의 하지 운동학 및 운동역학 자료를 획득하였다. 삼각경사 보행에서 최대 발목 배측굴곡각 및 모멘트와 최대 무릎 신전 모멘트가 평지보행과 비교하였을 때 증가하였다(p<0.05). 삼각경사의 상승경사 보행 시 $50^{\circ}$가 넘는 무릎 굽힘각과 그 시기에 발생하는 큰 무릎 신전 모멘트는 슬개대퇴증후군의 위험을 높일 수 있을 것으로 보인다. 또한 삼각경사의 하강경사 보행에서 증가된 발목 배측굴곡 운동범위는 비복근과 아킬레스건 부상 위험을 높일 수 있을 것으로 보인다.

• 한국체육학회지인문사회과학편
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• 제55권2호
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• pp.643-655
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• 2016

본 연구는 내리막 경사의 변화에 따른 노인집단과 젊은 성인집단의 운동역학적 보행분석을 통해, 두 집단 간 보행패턴의 차이를 비교 분석하여 노인들의 운동역학적 측면에서 낙상 요소를 파악하는데 목적이 있다. 20대 건강한 젊은 성인여성집단(yrs: 21.17±1.5)과 65세 이상의 건강한 노인여성집단(yrs: 66.67±1.33)을 대상으로 각각 18명씩 실험 참여자로 선정하였으며 트레드밀 위에서 선호속도로 평지, -7.5°, -15°의 세 가지의 경사조건에서 보행을 실시하였다. 노인집단은 성인집단에 비해 내리막 보행 시 신체중심의 좌우변위가 더 큰 것으로 나타났고(p<.05), 경사에 따라 무릎과 발목 관절의 발목 가동변위는 노인집단이 더 작은 것으로 나타났다(p<.05). 엉덩관절의 가동범위에서는 집단 간 차이가 나지 않았지만 노인집단의 최대 신전 각은 성인집단보다 작은 것으로 나타났다(p<.05). 또한, 내리막 보행 시, 성인집단보다 더 적은 무릎 신전모멘트가 작용한 것으로 나타났다(p<.05). 본 연구 결과 노인들은 내리막 보행 시 낙상 위험에 더욱 노출되고 불안정한 보행을 할 것이라는 예상과 달리 젊은 성인집단보다 더욱 안정적인 보행 전략을 세워서 걷는 것으로 나타났다. 본 연구를 통해 노인들의 보행특성 및 낙상과 관련된 운동역학적 변인을 수집하고, 노인의 낙상을 예방하기 위한 후속연구의 기초자료로서 도움을 줄 것이라 예상된다.

• 한국정밀공학회지
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• 제31권12호
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• pp.1141-1146
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• 2014

As life expectancy becomes longer, reduction of human muscular strength threatens quality of human life. Many robotic devices have thus been developed to support and help human daily life. This paper deals with a new type of in-wheel actuator that can be effectively used for the robotic devices. BLDC motor, drive board, brake, ARS (Attribute Reference System), and torque sensor are combined in the single actuator module. The torque sensor is used to recognize human intention and the in-wheel actuator drives walking aids in our system. Its feasibility was tested with the active walking aid device equipped with the in-wheel actuator. Based on it, we designed an admittance filter algorithm to react on uphill and downhill drive. By adjusting mass, damping, and spring parameters in accordance with the ARS output, it provided convenient drive to the old on uphill and downhill walks.

• 한국운동역학회지
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• 제24권2호
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• pp.139-149
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• 2014

The purpose of this study was to evaluate the effect of angle change of forefoot's adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over $-20^{\circ}$ ramp. Thirteen male university students (age: $25.4{\pm}3.9$ yrs, height: $176.2{\pm}5.1$ cm, weight: $717.4{\pm}105.0$ N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over $0^{\circ}$ and $20^{\circ}$ ramp with three different forefeet's EVA outsole (0, 10, $20^{\circ}$) in random order at a speed of $1.2{\pm}0.1$ m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in $20^{\circ}$ shoes compared to $0^{\circ}$ and $10^{\circ}$ ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot's adhesive outsole, indicating that the increment of shoes' angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in $20^{\circ}$ outsole compared to $0^{\circ}$ and $10^{\circ}$ ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

• 국제물리치료학회지
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• 제2권2호
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• pp.324-328
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• 2011

The purpose of this study is to measure the effect of change in heel height on lower extremities activity of young women on high-heeled shoes that young women prefer from more kinetic and realistic perspective as this study changes the degree of slope on a treadmill. The study subjects are 15 young and healthy women who do not have any external injuries or problem with walking and understand the purpose of this study clearly. They wore three different height of heels(1cm, 7cm, 12cm) and walked on a treadmill at a constant speed of 3km/h. EMG value of four muscles (anterior tibial muscle, gastrocnemius muscle, straight muscle of thigh, and biceps muscle of thigh) were collected when walking and the change according to the height of heels were analyzed using one-way ANOVA. Multiple comparison analysis on anterior tibial muscle and heel height showed that the group with 12cm heel showed significantly high muscle activation compared to the groups with 1cm and 7cm heels. The result of this study can be used for various perspectives from inferring and mediating problems caused by wearing high heels on different ground slopes for a long time.

• 한국환경생태학회지
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• 제9권1호
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• pp.49-55
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• 1995

본 연구는 계룡산 국립공원과 오대산 국립공원의 9개 등산로를 대상으로 등산로의 물리적 조건이 심장박동수에 미치는 영향을 밝히기 위하여 수행되었다. 산오르기 등산은 피검자가 에르고메타를 이용하여 측정한 최대심박수의 84~96%에 해당하는 고된 신체운동이며, 동일한 코스를 내려올 때의 최대심박수는 올라갈 때의 최대심박수에 약 78~93%에 해당하는 값을 나타내었다. 등산로의 경사도는 심박수에 영향을 미치는 것으로 나타났으나, 노폭은 심박수와 무관한 것으로 판단된다. 비시설 등산로에 비하여 나무 또는 돌계단식과 같은 등산로 노면재료가 심박수의 증가에 영향을 크게 미치는 것으로 나타났다.

• 대한물리의학회지
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• 제14권3호
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• pp.21-27
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• 2019

PURPOSE: This study examined the changes in the kinematic variables during walking on a downhill ramp according to the shoe heel height. METHODS: The subjects were 10 adult women with no history of musculoskeletal disorders who agreed to participate in the study. Data were collected using a motion analysis system (VICON) consisting of six infrared cameras. The slope was 120 cm in width, 200 cm in length, and 15 in inclination. To confirm the change in gait parameters (stride length, gait speed) and lower extremity joint angle according to the heel heights of the shoes, flat, 5 cm, and 10 cm heel shoes were prepared and walked alternately. RESULTS: As a result, both the stride length and walking speed showed significant differences according to the heel height between flat and 10 cm (p<.05). In the sagittal plane, there was no significant difference in the hip joint and knee joint, but a significant difference was observed in all events in the ankle joint on all heel heights (p<.05). In particular, the heel strike and mid stance events showed significant differences among all height conditions (p<.05). No significant difference was observed in any of the joint angle changes in the frontal plane (p>.05). CONCLUSION: As the shoe heel height increased, the instability increased and efforts to secure the stability were made, leading to a shortened stride length, walking speed, and angle of the ankle joint.