• 한국운동역학회지
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• 제31권1호
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• pp.30-36
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• 2021

Objective: The objective of the present study was to analyze the relationship between strength of the lower extremity's joints and their local dynamic stability (LDS) of gait in elderly women. Method: Forty-five elderly women participated in this study. Average age, height, mass, and preference walking speed were 73.5±3.7 years, 153.8±4.8 cm, 56.7±6.4 kg, and 1.2±0.1 m/s, respectively. They were tested torque peak of the knee and ankle joints with a Human Norm and while they were walking on a treadmill at their preference speed for a long while, kinematic data were obtained using six 3-D motion capture cameras. LDS of the lower extremity's joints were calculated in maximum Lyapunov Exponent (LyE). Correlation coefficients between torque of the joints and LyE were obtained using Spearman rank. Level of significance was set at p<.05. Results: Knee flexion torque and its LDS was negatively associated with adduction-abduction and flexion-extension movement (p<.05). In addition, ratio of the knee flexion torque to extension and LDS was negatively related to internal-external rotation. Conclusion: In conclusion, knee flexion strength should preferentially be strengthened to increase LDS of the lower extremity's joints for preventing from small perturbations during walking in elderly women.

• 한국전문물리치료학회지
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• 제13권2호
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• pp.16-25
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• 2006

The aim of this study was to investigate the kinematics of young adults during descent ramp climbing at different inclinations. Twenty-three subjects descended four steps at four different inclinations (level, $-8^{\circ}$, $-16^{\circ}$, $-24^{\circ}$). The 3-D kinematics were measured by a camera-based Falcon System. The data were analyzed using one-way ANOVA and the Student-Newman-Keuls test. The kinematics of descent ramp walking could be clearly distinguished from the kinematics of level walking. On a sagittal plane, the ankle joint was more plantar flexed at initial contact with $-16^{\circ}/-24^{\circ}$ inclination, was decreased in the toe off position with all inclinations (p<.001),and was decreased at maximum plantar flexion during the swing phase (p<.001). The knee joint was more flexed at initial contact with the $-24^{\circ}$ inclination (p<.001), was more flexed in the toe off position with all inclinations (p<.001), and was more flexed at minimum flexion during stance phase and at maximum flexion during swing phase with $-16^{\circ}$, $-24^{\circ}$ inclination (p<.001). The hip joint was more flexed in the toe off position with $-16^{\circ}$, $-24^{\circ}$ inclination and was deceased at maximum extension during stance phase with $-16^{\circ}$, $-24^{\circ}$ inclination (p<.05). In the frontal plane, the ankle joint was more everted at maximum eversion during stance phase with $-16^{\circ}/-24^{\circ}$ inclination (p<.01) and was decreased at maximum inversion during swing phase with $-16^{\circ}$, $-24^{\circ}$ inclination (p<.01). The knee joint was more increased at maximum varus during stance phase with $-16^{\circ}/-24^{\circ}$ inclination (p<.001). The hip joint was deceased at maximum adduction during stance phase with $-24^{\circ}$ inclination (p<.05). In a horizontal plane, only the knee joint was increased at maximum internal rotation during stance phase with $-24^{\circ}$ inclination (p<.05). In descent ramp walking, the different gait patterns occurred at an inclination of over $16^{\circ}$ on the descending ramp in the sagittal and frontal planes. These results suggest that there is a certain inclination angle or angular range where subjects do switch between level walking and descent ramp walking gait patterns.

• 한국운동역학회지
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• 제16권4호
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• pp.39-47
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• 2006

This study long jump action to each situation on a chessboard and section of sight disabled person and normal person through third dimension reflex analysis mechanical special quality because do comparative analysis sight disabled person's exercise ability and technology structure of action that run understand. As can do better without danger of injury map and training of exercise item that action that run is included, do offer of pabulum by purpose. Through this study, conclusion is as following. 1. Sight disabled persons' long jump average recording (121.84cm) showing normal persons' average recording (259.27cm) and much differences, show that motion of body is not big to Touch-down from Ready action. 2. Each phase body center composition(r) average speed displayed result that it is more meaning more than Each phase time required. 3. Began in line carriage without body back stretching in 1 situation on Event one are sight disabled persons. Was expose that do not bend enough knee and ankle than normal person in Event two. Was expose that body is not drooped for surface of land in Event three, and knee and ankle were expose that do not unfold easily than normal person. Was expose that do not bend enough on Touch-down knee by relation that can not grasp position of the floor in Event four. 4. When taking off, the average of horizontal speed of body center are 1.80m/sec for blind people and 3.53m/sec for the normal. In this connection, the study shows that the difference of horizontal speed between the blind and the normal is bigger than difference of vertical speed, which are 1.56m/sec for the blind and 1.98m/sec for the normal. Also, composite speed also shows us big difference between 2.41m/sec of the blind and 4.07m/sec of the normal. The speed body center of take-off was expose that average adjuster are big width of deceleration than average - beginning disabled person's average by 2.23m/sec - 1.71m/sec in the vertical speed. 5. If examine change of high and low for z Sign of right hand, change of high and low showed as is small than normal person is sight obstacle, and all hand movements are small and was expose that do not use enough reaction of body as well as in ready action.

• 한국운동역학회지
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• 제16권1호
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• pp.101-108
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• 2006

The purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes. Twelve male middle school students (age: $15.0{\pm}0.0\;yrs$, height: $173.6{\pm}5.0\;cm$, weight: $587.6{\pm}89.3\;N$) who have no known musculoskeletal disorders were recruited as the subjects. Kinematic data from six S-VHS camcorders(Panasonic AG456, 60 fields/s) and GRF data from two force platform; (AMII OR6-5) were collected while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and GRF recordings. GRF data were filtered using a 20 Hz low pass Butterworth. digital filter and further normalized to the subject's body weight. For each trial being analyzed, five critical instants and four phases were identified from the recording. Temporal parameters, GRFs, displacement of center of pressure (DCP), and loading and decay rates were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p <.05). Vertical GRFs at heel contact increased and braking forces at the end of initial double limb stance reduced significantly when going from jogging shoe to roller shoe condition. Robbins and Waked (1997) reported that balance and vertical GRF are closely related It seems that the ankle and knee joints are locked in an awkward fashion at the heel contact to compensate for the imbalance. The DCP in the antero-posterior direction for the roller shoe condition was significantly less than the corresponding value for the jogging shoe condition. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the DCP for the roller shoe condition was restricted The results indicate that walking with roller shoes had little effect on temporal parameters, and loading and decay rates. It seems that there are differences in GRF characteristics between roller shoe and jogging shoe conditions. The differences in GRF pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine muscle activation patterns and joint kinematics during walking with roller shoes.

• 한국응용과학기술학회지
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• 제38권2호
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• pp.532-542
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• 2021

본 연구의 목적은 골프 스윙 시 3가지 스탠스에서 클럽헤드 스피드와 볼의 정확성을 유지하기 위한 신체 전략을 하지의 운동학적 변인과 지면반력 변인을 통하여 알아보고자 하였다. 연구의 대상은 공식 핸디캡이 2인 남자골프선수 10명으로 하였다. 모든 대상자들은 스탠스 조건(스퀘어, 오픈, 클로즈드)에 따라 어드레스 자세를 유지한 후 스윙을 수행하였다. 3차원 동작분석 시스템과 지면반력기를 이용하여 각 스탠스에 따라 7번 아이언 풀스윙을 수행한 결과를 산출하였다. 연구결과로 신체중심의 변위, 고관절 각변위, 무릎관절 각변위는 차이가 나타나지 않았다. 발목관절 각변위는 어드레스부터 다운스윙까지 왼쪽에서 오픈 스탠스가 저측굴곡이 크게 수행되었고, 오른쪽에서 클로즈드 스탠스에서 저측굴곡이 크게 수행되었다. 지면반력에서 전후, 수직은 차이가 없었지만, 어드레스부터 테이크백까지 왼발은 오른쪽 방향, 오른발은 왼쪽 방향의 힘이 오픈이 클로즈드 스탠스보다 크게 나타났다. 결론적으로 다양한 스탠스에도 불구하고, 임팩트 시 동일한 자세를 유지하는 것이 클럽헤드 스피드와 볼의 방향에 긍정적으로 작용되는 것으로 판단된다.

• 한국운동역학회지
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• 제18권4호
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• pp.99-107
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• 2008

본 연구는 주니어 역도 선수 인상 종목의 주요 국면인 Deadlift 동작 시 스탠스 유형에 따른 운동학적 변인을 비교 분석하여 선수들의 경기력 향상과 훈련 시 기초자료를 제공하기 위하여 실시하였다. 본 연구에서 8자형은 11자형에 비해 바벨과 신체의 발란스에 적합한 소요시간을 보였고 바벨을 끌어올리는데 요구되는 인체중심의 전 후, 좌 우이동범위를 작게하여 인체의 안정성을 유도하였다. 또한 8자형의 인체중심속도와 바벨의 속도는 E3(바가 고관절에 도달할 때)를 지나면서 상방향으로 바를 끌어올리는데 유리한 조건의 큰 속도를 발휘하는 것으로 나타났다. 그리고 몸통과 고관절 무릎, 발목 및 스탠스 각도에서 8자형은 11자형에 비해 인체의 안정성을 유지하면서 순간적인 힘을 발휘하는데 유리한 조건을 갖추고 있는 것으로 나타났다.

• 한국운동역학회지
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• 제26권1호
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• pp.11-20
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• 2016

Objective: This study aimed to compare biomechanical data between elite and beginner cyclists during cycle pedaling by performing a comparative analysis and to provide quantitative data for both pedaling performance enhancement and injury prevention. Methods: The subjects of this study included 5 elite cyclists (age: $18{\pm}0years$, body mass: $64.8{\pm}9.52kg$, height: $173.0{\pm}4.80cm$) and 5 amateur cyclists (age: $20{\pm}0years$, mass: $66.6{\pm}2.36kg$, height: $175.6{\pm}1.95cm$). The subjects pedaled on a stationary bicycle mounted on rollers of the same gear (front: 50 T and rear: 17 T = 2.94) and cadence of 90. The saddle height was adjusted to fit the body of each subject, and all the subjects wore shoes with cleats. In order to obtain kinematic data, 4 cameras (GR-HD1KR, JVC, Japan) were installed and set at 60 frames/sec. An electromyography (EMG) system (Telemyo 2400T, Noraxon, USA) was used to measure muscle activation. Eight sets of data from both the left and right lower extremities were obtained from 4 muscles (vastus medialis oblique [VMO], vastus lateralis oblique [VLO], and semitendinosus [Semitend], and lateral gastrocnemius [Gastro]) bilaterally by using a sampling frequency of 1,500 Hz. Five sets of events ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$, and $360^{\circ}$) and 4 phases (P1, P2, P3, and P4) were set up for the data analysis. Imaging data were analyzed for kinematic factors by using the Kwon3D XP computer software (Visol, Korea). MyoResearch XP Master Edition (Noraxon) was used for filtering and processing EMG signals. Results: The angular velocity at $360^{\circ}$ from the feet was higher in the amateur cyclists, but accelerations at $90^{\circ}$ and $180^{\circ}$ were higher in the elite cyclists. The amateur cyclists had greater joint angles at $270^{\circ}$ from the ankle and wider knee joint distance at $0^{\circ}$, $180^{\circ}$, and $360^{\circ}$ than the elite cyclists. The EMG measurements showed significant differences between P2 and P4 from both the right VLO and Semitend. Conclusion: This study showed that lower body movements appeared to be different according to the level of cycle pedaling experience. This finding may be used to improve pedaling performance and prevent injuries among cyclists.

• 한국운동역학회지
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• 제15권4호
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• pp.25-42
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• 2005

The study was to investigate kinematic difference between flexed and extended type of knee during Jigeo-Cha-Gi in Taekwon-Do. For this subjects participated were consisted of weights of fin (1), bantam (1) and welter class(1) of male 3 national representative level skilled in two type(flexed and extended type) of Jigeo-Cha-Gi. 3D cinematography analysis was performed for motion analysis and Kwon 3D ver. 3.1) was used for 3D coordinates & analysis variables calculation. In Temporal variable there was no significant difference statistically in all phases & total elapsed time between flexed and extended type, but flexed type was delayed more 0.016 sec than extended type. In displacement of COG there was significant difference in level of p<.05 showing longer mean 6.13 cm in case of flexed type than extended type in displacement of COG during all phase and too significant difference in level of p<.01 showing longer mean 4.4 cm in case of flexed type than extended type in displacement of COG in follow through phase. In velocity of COG there was significant difference in level of p<.001 showing higher mean 15.53cm/s in case of flexed type than extended type in velocity of COG(Y direction) during targeting phase and peak velocity(Y) was more fast 8.74 cm/s in extended type than flexed type. In velocity of leading leg in forward direction(Y) there was significant difference in level of p<.05 showing higher thigh mean value in case of flexed type than extended type but showing higher foot mean value in extended type at level of p<.001 than flexed type in velocity of COG(Y direction). In velocity of leading leg in vertical direction(Z) there was no significant difference in the second & third phase in case of vertical velocity level, but momentum transferred efficiently form proximal to distal endpoint. In front-back & right-left orientation angle of trunk there was possibility of more stable Jigeo-Cha-Gi in extended than flexed type by decreasing in right-left orientation angle of trunk. In relative angle of lower leg(hip, knee, ankle) there was significant difference in level of p<.001 showing longer mean 32.74 deg. in case of flexed type than extended type in hip joint during the second phase but maintained insufficient extended knee of mean 168 deg. in targeting phase.

• 한국운동역학회지
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• 제15권3호
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• pp.161-173
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance. The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to open stance patterns during forehand stroke in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVlEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head angle were defined 1. In three dimensional maximum linear velocity of racket head the X axis showed $11.41{\pm}5.27m/s$ at impact, not the Y axis(horizontal direction) and the z axis(vertical direction) maximum linear velocity of racket head did not show at impact but after impact this will resulted influence upon hitting ball It could be suggest that Y axis velocity of racket head influence on ball direction and z axis velocity influence on ball spin after impact. the stance distance between right foot and left foot was mean $74.2{\pm}11.2m$. 2. The three dimensional anatomical angular displacement of shoulder joint showed most important role in forehand stroke. and is followed by wrist joints, in addition the movement of elbow joints showed least to the stroke. The three dimensional anatomical angular displacement of racket increased flexion/abduction angle until the impact. after impact, The angular displacement of racket changed motion direction as extension/adduction. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed extension all around the forehand stroke. The angular displacement of trunk in adduction-abduction showed abduction at the backswing top and adduction around impact. while there is no significant internal-external rotation 4. The three dimensional anatomical angular displacement of hip joint and knee joint increased extension angle after minimum of knee joint angle in the forehand stroke, The three dimensional anatomical angular displacement of ankle joint showed plantar flexion, internal rotation and eversion in forehand stroke. it could be suggest that the plantar pressure of open stance during forehand stroke would be distributed more largely to the fore foot. and lateral side.

• 한국응용과학기술학회지
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• 제40권4호
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• pp.642-649
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• 2023

본 연구의 목적은 허벅다리걸기 시 유도 선수들의 무릎 관절 부상 경험이 운동학적 요인과 압력 중심 요인들에 미치는 영향을 분석하는데 있었다. 본 연구에는 허벅다리걸기를 특기로 하는 오른손잡이 남자 대학 유도 선수 중 최근 2년 이내 무릎 관절 부상 경험이 있었던 13명(연령, 20.69.1±0.75 세; 신장, 172.85±4.81 cm; 체중, 74.92±5.51 kg; 경력, 8.92±0.95 세)과 상해 경험이 없었던 13명(연령, 21.08.1±0.76 세; 신장, 172.54±6.32 cm; 체중, 76.62±9.09 kg; 경력, 9.46±0.94 세)이 두 그룹으로 나뉘어 피험자로 참여하였다. 두 그룹의 발목, 무릎, 힙 관절각도 변인과 압력 중심 가동범위와 속도 요인들의 차이를 분석하였다. 그 결과, 부상 경험 그룹은 부상 경험이 없었던 그룹에 비해 허벅다리걸기 기술 발휘 시 한발 지지 구간 중 E3에서의 무릎 관절 굴곡 각도와 E4에서의 힙 관절 신전 각도에서 작은 수치를 나타내었다. 더불어 부상 경험 그룹은 부상 경험이 없었던 그룹에 비해 한발 지지 구간에서 압력 중심 가동범위와 전방 이동 속도 요인에서도 낮은 수치를 나타내었다.