• 한국전문물리치료학회지
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• 제6권3호
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• pp.11-21
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• 1999

Human balance is maintained through a complex process involving sensory detection of body motions, integration of sensorimotor information within the central nervous system, and execution of appropriate musculoskeletal responses. The basic task of balance is to position the body center of gravity (COG) over some portion of the support base. When the COG extends beyond the base of support, the person has exceeded the limits of stability (LOS). At this point, a step or stumble is required to prevent a fall. Automatic postural responses operate to keep the COG over the base of support. They are a set of functionally organized, long-loop responses that act to keep the body in a state of equilibrium. There are four commonly identified automatic postural responses, or strategies. These are ankle strategy, hip strategy, suspensory (knee) strategy, and stepping strategy. Thus, the purpose of this study was to evaluate the LOS using various knee strategies. Forty subjects participated in this study. The subjects were comprised of 20 males and 20 females who were without neurologic, orthopaedic or balance performance impairments. The LOS was measured with a Balance Performance Monitor (BPM) Dataprint Software Version 5.3. The results of this study were as follows: 1) Knee joint angle which is to increase stability of standing balance with using knee strategy was at mid-range. 2) There were statistically significant differences in anteroposterior LOSs according to the knee strategy. 3) There were no statistically significant differences in mediolateral LOSs according to the knee strategy. 4) There were statistically significant differences of anteroposterior LOSs with using knee strategy according to gender. 5) There were no statistically significant differences in mediolateral LOSs with using knee strategy according to gender.

• 한국운동역학회지
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• 제16권2호
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• pp.85-95
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• 2006

The purpose of this study of which 10 University students in their twenties are the objects was to examine the causal differences of kinematic and electromyography during power walking and normal gait. We came to the following conclusions. 1) It took less time to stance phase, swing phase and whole gait time during power walking compared with normal gait. 2) During power walking, the step length and step length and lower limb length are longer than that of normal gait. 3) During power walking, ankle joint angle became more plantar flexed at LIC and RTO, knee joint angle become more flexed, so did hip joint angle at LIC and RTO. Besides during power walking the shoulder joint angle movement was bigger and elbow joint angle was more flexed as the trait of power walking. 4) During power walking, through out the phase the muscle activity of all muscle was higher expecially the muscle activity of Biceps brachii, gastrocnemius medialis, gastrocnemius lateralis, Soleus was higher. Therefore during power walking, one's scope of activity and muscle activity is relatively higher than those of normal gait, so power walking helps one strengthen muscular power and energy metabolism. This will be useful information for those who are interested in diet and well-being.

• 한국운동역학회지
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• 제13권3호
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• pp.163-180
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• 2003

This paper aims at collecting the guantitative data of kenematic variables by analysing the gait patterns of the normal adult men and the handicapped. The gait motions were taped with 4 video cameras, the cinematographic analyses were performed by the DLT technique of three dimensional image treatment. The following results were obtained in the analysis of the variables: 1. The ratio of stance time and swing time did not show any significant difference in the groups of the normal men and the handicapped when both foot of the former and the right feet of the latter were compared. The stride peeriod time of these two groups were 1.12 and 1.11 second, respectively. 2. In the handicapped group, the step width was wider, the step length and stride length were shorter, and especially, the step length of the right foot was shorter, 3. The small vertical displacement of left toes of the handicapped group showed that the heal contact and the left midstance are almost simultaneous. 4. The two groups have almost the same horizontal displacement of the center of gravity and the same vertical rate of extension. In view of the velocity of the center of gravity the normal adults showed the constant speed of movement. However, the handicapped adults were reduced from the right midstance to the right toe-off. 5. The handicapped showed prominently low angle on the left toe-off in the ankle joint angle, they also had the tendency to walk in the patterns of extended knee in the knee joint angle. Both the handicapped and the normal had the hyperextension on the toe-off in the hip joint angle. In the back and front angle of body, both showed the slightly back-sided walking positions. 6. Both groups had the abduction of both feet in foot placement angle, but the handicapped did not show serious abduction of left midstance.

• 한국운동역학회지
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• 제25권3호
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• pp.335-342
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• 2015

Objective : The purposes of this study was to analyze the effects of the stirrup length fitted to the rider's lower limb length and it's impact on less skilled riders during trot in equestrian events. Methods : Participants selected as subjects consisted of less skilled riders(n=5, mean age: $40.02{\pm}10.75yrs$, mean heights: $169.77{\pm}2.08cm$, mean body weights: $67.65{\pm}7.76kg$, lower limb lengths: $97.26{\pm}2.35cm$, mean horse heights: $164.00{\pm}5.74cm$ with 2 type of stirrups lengths(lower limb ratio 74.04%, and 79.18%) during trot. The variables analyzed consisted of the displacement for Y axis and Z axis(head, and center of mass[COM]) with asymmetric index, trunk front-rear angle(consistency index), lower limb joint(Right hip, knee, and ankle), and average vertical forces of horse rider during 1 stride in trot. The 4 camcorder(HDR-HC7/HDV 1080i, Spony Corp, Japan) was used to capture horse riding motion at a rate of 60 frames/sec. Raw data was collected from Kwon3D XP motion analysis package ver 4.0 program(Visol, Korea) during trot. Results : The movements and asymmetric index didn't show significant difference at head and COM, Also, 74.04% stirrups lengths in trunk tilting angle showed significant difference with higher consistency than that of 79.18% stirrups lengths. Hip and knee joint angle showed significant difference with more extended posture than that of 74.04% stirrups lengths during trot. Ankle angle of 79.18% stirrups length showed more plantarflexion than that of 74.04% stirrups lengths. Average vertical force of rider showed significant difference with higher force at 79.18% stirrups lengths than that of 74.04% stirrups lengths during stance phase. Conclusion : When considering the above, 74.04% stirrups length could be effective in impulse reduction with consistent posture in rather less skilled horse riders.

• 한국운동역학회지
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• 제13권1호
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• pp.155-171
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• 2003

The purpose of this study was to analyze the kinematic variables of over head kick(OHK) in soccer with three dimensional analysis technique and show the kinematic characteristics of it. The 7 subjects were university football player who have been playing football more than 7 years. The OHK was filmed on 16mm video camera(30frame/sec.) kinematic variables were temporal, postures, and COG(center of gravity). The mean values and the standard deviation for each variables were obtained and used as basic factors for examining characteristics of OHK. The results of this analysis were as follows : Temporal variables : The total time elapsed(TE) of OHK was $0.95{\sim}1.14sec$, the 1st phase was 0.35sec., 2nd phase was 0.46sec., and 3rd phase was 0.22sec.. Posture variables : When subjects performed OHK at the impact event, the ankle and knee angle of kicking foot were more extend than supporting foot. but the hip angle of supporting foot were more extend than kirking foot. Moving distance of the center of mass of the both foot. When subject performed OHK at the impact event, the range of distance on mediolateral direction aspect into right left shoulder line, anteroposterior direction aspect was $20.9{\pm}10.5cm$, vertical direction aspect was $92.3{\pm}19.9cm$. Angular velocity : the faster angular velocity of knee ankle on the kicking foot pew form jump position to landing position, the faster velocity of ball became. C. O. G. variables. When subject performed OHK at the impact event, upper part of the body was getting lower, lower part of the body was getting higher.

• 한국융합학회논문지
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• 제10권9호
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• pp.63-68
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• 2019

무릎 과다 폄을 가진 대상자에게 비대칭적 선 자세와 같은 외부적 요소가 추가되게 되면 무릎 관절에 가해지는 체중 지지가 더 증가하게 되며, 무릎 뒤쪽 구조들의 과신장이 유발된다. 이는 무릎 과다 폄 변형을 증가시킬 뿐만 아니라, 앞 십자인대와 같은 무릎 주변 연부조직의 변형 및 손상을 유발하는 요인이 될 수 있다. 따라서, 비대칭적 선 자세가 무릎 관절의 위치와 하지 근육의 활성도에 어떠한 영향을 미치는지 알아보는 것이 이 연구의 목적이다. 33명의 자발적 참여대상자들이 연구에 참여하였으며 총 60개의 다리에 대하여 무릎 과다 폄군, 정상군으로 나누어 하지근육의 근 활성도 및 무릎 폄 각도를 측정하였다. 비대칭적 선 자세 시, 무릎 관절 폄 각도와 장딴지근의 근 활성도 값은 정상군과 무릎 과다 폄 군 사이의 통계학적 유의한 차이가 나타났다. 결과를 토대로 비대칭적인 선 자세가 무릎의 과다 폄을 증가시키는 요인이 됨을 확인하였다. 따라서, 무릎 정렬에 이상을 가진 대상자들에게는 정상적인 정렬 회복과 함께 대칭적인 선 자세를 유지할 수 있도록 하는 치료적 중재 수립에 도움을 줄 것이며, 추후 엉덩관절과 발목관절의 영향을 포함한 조사연구가 필요하겠다.

• 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.

• 한국운동역학회지
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• 제30권1호
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• pp.51-61
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• 2020

Objective: The purpose of this study is to analyse and comparison the differences of kinematic variables for Fente skill in Fencing. Method: For this, 15 people were selected as 5 beginners with less than 2 years of experience, 5 intermediate-class people with more than 2 years and less than 4 years, and 5 experts-class people with more than 4 years. Through the comparison of Marche Fente motion according to proficiency, for the necessary time, travel distance, the kinematical factor of joint angle, oneway ANOVA was performed in order to identify differences according to variables by phase. Results: The time required for each phase was shown to be shorter for all phases experts than for beginners and intermediates. At the horizontal displacement of the foot, the right foot left out the last phase and the experts appeared long. The left foot showed short beginners in all phases. The angle of forward lean showed that the angle of forward lean was tilted forward by the experts of all phases. There was a difference between the left and right joint angles of the lower limb, both of the ankle, knee and hip joints. Conclusion: In overall, Beginners should quickly widen the distance of their feet when they make a Fente movement. The beginner shall tilt the upper body forward in order to increase the angle of forward lean. The beginner shall, in the last phase, have a smaller angle on the hip joint.

• 한국운동역학회지
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• 제19권3호
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• pp.435-448
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• 2009

본 연구는 노인의 계단과 경사로 오르기와 평지보행 동안 하지의 운동학적 변화를 분석하는 것이었다. 건강한 노인 14명(남:10, 녀:4)이 실험에 참여하였으며 측정도구는 삼차원동작분석기인 Vicon system(Vicon, Oxford Metrics, England)을 사용하였다. 보행주기 각 시점에서 하지 관절의 각도 변화를 보행 조건(평지, 계단, 경사로)에 따라 알아보기 위해 일요인 반복측정 분산분석(one-way repeated measure of ANOVA)을 사용하였다. 전후면상에서 골반은 평지 보행에서 보행 주기 동안 전방굴곡이 나타났으며 계단과 경사로 오르기에서 전방굴곡이 증가하였다. 고관절과 슬관절는 모두 평지보행과 비교해 계단 오르기에서 굴곡이 더 증가하였다. 족관절은 평지보행과 비교해 경사로 오르기에서 굴곡이 더 증가하였다. 좌우면상에서 보행 주기 동안 평지보행과 비교해 계단 오르기에서 골반이 크게 올라갔으며 고관절도 계단 오르기에서 내전과 외전의 변화가 크게 나타났다. 또한 슬관절도 계단 오르기에서 내반이 증가하였고 족관절 역시 계단 오르기에서 내번이 증가하였다. 수평면상에서 보행 주기 동안 골반은 평지 보행과 비교해 계단과 경사로 오르기에서는 내회전이 대체로 증가하였고 고관절은 계단과 경사로 오르기에서 내회전이 증가하였으나 통계적으로 유의한 차이는 없었다. 슬관절은 계단 오르기에서 대체적으로 내회전이 증가하였고 족관절은 계단 오르기에서 대체적으로 외회전이 증가하였다. 이러한 결과는 노인의 계단과 경사로 오르기는 평지 보행과 비교해 하지의 운동학적 보행 변수들을 크게 변화시키는 것을 알 수 있었다.

• 한국운동역학회지
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• 제30권1호
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• pp.17-25
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• 2020

Objective: The purpose of this study is to provide a better understanding of long turn mechanism by describing long turns after kinematic analysis and provide skiers and winter sports instructors with data through which they are able to analyze right postures for turns in skiing in a systematic, rational and scientific manner. Method: For this, a mean difference of kinematic variables (the center of gravity (CG) displacement of distance, trajectory, velocity, angle) was verified against a total of 12 skiers (skilled and unskilled, 6 persons each), regarding motions from the up-start to down-end points for long turns. Results: First, concerning the horizontal displacement of CG during a turn in skiing, skilled skiers were positioned on the right side at the upstart and edge-change points at a long turn. There was no difference in anteroposterior and vertical displacements. Second, in terms of CG-trajectory differences, skilled skiers revealed a significant difference during a long turn. Third, regarding skiing velocity, skilled skiers were fast at the edge-change and maximum inclination points in long turns. Fourth, there was no difference in a hip joint in terms of a lower limb joint angle. In a knee joint, a large angle was found at the up-start point among skilled skiers when they made a long turn. Conclusion: In overall, when skilled and unskilled skiers were compared, to make a good turn, it is required to turn according to the radius of turn by reducing weight, concerning the CG displacement. Regarding the CG-trajectory differences, the edge angle should be adjusted via proper inclination angulation. In addition, a skier should be more leaned toward the inside of a turn when they make a long turn. In terms of skiing velocity, it is needed to reduce friction on snow through the edging and pivoting of the radius or turn according to curvature and controlling ski pressure. Regarding a lower limb joint angle, it is important to make an up move by increasing ankle and knee angles instead of keeping the upper body straight during an up motion.