달리기 시 신체 충격 크기와 흡수의 성차

류지선 한국운동역학회 2005 한국운동역학회지 Vol.15 No.1

J. S. RYU. Gender differences in the impact magnitude and its attenuation during running. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, pp. 91-109, 2005. The goal of this research was to determine whether gender differences exist in impact force and impact shock variables at stance phase during a preferred running. Ten male and ten female subjects volunteered to participate in this study. Impact force was quantified by using a surface-mounted force plate. In addition, Axial accelerations of the tibias and mouth were measured using low-mass accelerometers. Comparison of parameters relating to impact force and impact shock which attained from time domain, and impact shock parameters which were analyzed in frequency domain were made between genders. The conclusions based on results were as follows; 1. There were no significantly differences in impact force, mouth and tibia acceleration peak in time domain between two genders. 2. The male group was greater in impact shock peak of PSD(power spectral density) at the tibia than female group(p<05), but no differences in active impact of FSD at the tibia and the mouth between two genders. 3. Female subjects exhibited that a peak of impact shock attenuation analyzed in frequency domain moved toward a high frequency, but no difference in time domain between two genders.

뒤 공중 돌아 내리기 동작의 운동학적 특성 비교

류지선,한충식 韓國體育大學校附屬 體育科學硏究所 1994 韓國體育大學校附屬 體育科學硏究所論文集 Vol.13 No.1

The purpose of this study were to compare the kinematic variables of the skilled group with those of the less-skilled group in salto backward tucked vault landing. The subjects were selected 6 gymnasts from H university and were divided into two groups by skill level. The results were as follows, 1. There was no significant difference between two groups in the elapsed time for performing movement. 2. The skilled group showed higher score than the less-skilled in the height of C. G after jump. 3. There was no difference between two groups in the angle of flexion on the hip joint and the knee joint during the rotation phase. 4. The skilled group revealed higher score than less-skilled in the angle of the flexed hip joint and of vector C. G during the landing phase. 5. The angular velocity on the selected joint was not significantly different between two groups. However, the change pattern of the angular velocity in the total phase showed remarkable characteristics in the skilled group. 6. There was no difference between two groups in the changing velocity of C. G during the rotation and landing phase.

링 앞 휘돌아 물구나무서기 동작의 운동학적 분석

류지선,정남주,강병의 韓國體育大學校附屬 體育科學硏究所 1997 韓國體育大學校附屬 體育科學硏究所論文集 Vol.16 No.1

The purpose of this study is to examine the kinematical factors of Felge upward with straight arms to handstand motion, and to grope for the better Felge motion or dismount motion using the Felge motion on the Rings. As the subjects, six gymnasts(KOR 2, JPN 2, CHN 2) who participated in the 1997 Pusan East Asian Games(men's team competition Ⅰ). Two S-VHS video cameras were used for the data collection. The Direct Linear Transformation(DLT) technique was employed to obtain 3-D position coordinates of 30 control object points and 18 landmarks. A cubic spline function was used for smoothing and differentiation. And the following conclusions were drawn; 1. Down swing phase : It indicated that the longer vertical and horizontal displacement of CM were the smaller in vertical position of CM after the first handstand. Also it showed that the large extension of shoulder and hip joint resulted in the fast downward velocity at the Beating. 2. Beating swing phase : It indicated that the factors influencing the angular velocity of shoulder and hip joints and the horizontal velocity of the CM were the large downward vertical velocity during downswing phase, and the hip angle and position at the Beating. 3. Felge swing phase : It indicated that the large upward velocity and the small angular velocity of the shoulder and hip joints and the small horizontal velocity of the CM have the advantage of performing the last handstand motion.

평행봉 Healy 버티기 동작의 3차원 운동학적 분석

류지선,강병의 한국운동역학회 1997 한국운동역학회지 Vol.7 No.1

The purpose of this study is to examine the kinematical mechanism on Healy rwist to reward swing in support motion, and to grope for the better swing technique on the parallel bar. The subjects were four national ranked gymnasts who participated in the 1996 olympic game and four collegiate gymnasts. 2 S-VHS vedio caneras were used for the three-dimentional cinemerographical analysis. Also a rectangular shape control point containing markers of known coordinates, which encompassed the space of movement, was constructed and filmed to permit caliblation of the movement, After the filming of the control point it was removed and the Healy twist to reward swing in support motion techniques of each subject were filmed. And for the synchronization of three cameras, it was used the moment of braking out the ballon as the syn-event. The Direct Linear Transformation(DLT) technique was employed to obtain 3-D position coordinates and a cubic spline function was used for smoothing and differentiation. And the selected kinematical variables were the leaning arms angles at release, the leaning arms gngles at regrasp, the shoulder and hip angle, the velocity change of the center of the mass and the horizontal and vertical displacement of the center of the mass, T-test was used to test for differences between the skilled and the less-skilled gymnasts in the selected kinematical variables using SPSS-PC statistical program. Based on the results of this study, the following conclusions are drawn; 1) Angle Variable There are statistically no significant difference between two group in the all of the angle variables such as leaning arm of at release & at regrasp, shoulder & hip angle of at regrasp. but The mean values between two group are all the difference. The skilled group all the larger angles than the less-skilled group. 2) Displacement Variable(center of mass) There are statistically no significant difference between two group in the all of the displacement variables at each phase, but the mean values between two group are all the difference. The skilled group showed the longer displacement than the less-skilled group in all the horizontal displacement at each phase and vertical displacement at regrasp, vertical position. The less-skilled group showed the longer vertical displacement than the skilled group at release and horizontal position. 3) Velocity Variable(center of mass) There are statistically no significant difference between two group in all of the velocity variables at all phase. but there are all the difference between the mean value of groups. The skilled group showed the higher resultant velocity at 1st and 2nd phase and the less-skilled group showed the higher resultant velocity at 3rd phase. The skilled group showed the higher horizontal velocity at 1st phase and the lower horizontal velocity at 2nd and 3rd phase than the less-skilled group. The skilled group showed the lower vertical velocity except 2nd phase than the less-skilled group. In summary, the skilled group performs the Healy twist to reward swing in support motion with the larger angle variables. This leads to increase the leaning arm angle and the height of regrasp position. The increased leaning arm, shoulder and hip angles lead to increase the velocity of the Healy motion. Therefore, the body position without crouch at all phase and the higher center of the mass at regrasp make easy to perform more than skills after the Healy swing motion.

평균대 경기 시 앞 공중돌기 동작에 대한 운동학적 분석

윤희중,류지선,김동민,김영란 한국운동역학회 2000 한국운동역학회지 Vol.9 No.2

본 연구는 평균대에서 수행되는 앞 공중돌기 동작의 효율적인 동작을 연기하는데 필요한 정보를 제공하기 위한 운동학적 요인을 살펴보는 데 있다. 연구대상은 부산동아시아 체조경기대회(1997년)평균대 종목별 결승에 참가한 한국선수 1명, 카자흐스탄 2명, 일본선수 1명을 대상으로 3차원 영상 분석을 통하여 운동학적 요인을 분석한 결과 다음과 같은 결론을 얻었다. 1. 각국면별 소요시간 도움닫기 시간은 스텝시간이 대상자별로 다르게 실시함으로서 수행시간간에 차이를 보였다. 도약 시간은 선행연구 결과에 비해 본 연구의 대상자들이 보다 짧은 시간을 나타냈으며, 체공시간은 길게 소요하고 있는 것으로 나타났다. 2. 체공 및 착자시 인체중심 높이는 선행연구된 마루 운동의 수행 결과들 보다는 다소 낮게 나타났다. 3. 도약시 인체중심 속도는 수직속도보다 수평속도가 높게 나타났다. 4. 도약 및 착지시 선정된 각 관절의 각도는 선행연구 결과들 보다 무릎각을 제외한 발목, 고관절 각도에서 적은 각도를 나타내 불안정한 착지를 수행하는 것으로 나타났다. The purpose of this study was to analyze the kinematic variable of a forward somersault motion in balance beam. Two video cameras were used for 3-dimentional analysis. The subjects were four female gymnasts who is participated in the '97 east asian game. The conclusions are follows. 1. Time of each phase The time of run-up was shown a difference between performance time as type of step patterns of each subjects. The time of support was display a more short time in the gymnasts of present study compared to gymnasts of previous study, and it was shown a long time in the flight phase. 3. The velocity of center of gravity in supports phase was shown more high levels in horizontal velocity than vertical velocity. 4. The angle of each joint in support and landing was display a low angles in ankle and hip joint angles except to knee joint angles. Therefore, it was performing a unbalanced landing.

보행 시 노인의 상체 움직임에 대한 3차원적 분석

김희수,윤희중,류지선,김태삼 한국운동역학회 2004 한국운동역학회지 Vol.14 No.3

H. S. KIM, H. J. YOON, J. S. RYU, T. S. KIM. The Three Dimensional Analysis of the Upper Body's Segments of the Elderly during Walking. Korean Journal of Sport Biomechanics, Vol. 14, No. 3, pp. 1-15, 2004. The purpose of this study was to investigate the kinematic variables of the upper part of the body for 8 elderly men during walking. For this study, kinematic data were collected using a six-camera (240Hz) Qualisys ProReflex system. The room coordinate system was right-handed and fixed in space, with righted orthogonal segment coordinate systems defined for the head, trunk, and pelvis. Based on a rigid body model, reflective marker triads were attached on the 3 segments. Three-dimensional Cartesian coordinates for each marker were determined at the time of recording using a nonlinear transformation(NLT) technique with ProReflex software (Qualisys, Inc.). Coordinate data were low-pass filtered using a fourth-order Butterworth with cutoff frequency of 6Hz. Three-dimensional angles of the head, trunk, and pelvis segment were determined using a Cardan method. On the basis of each segment angle, angle-angle plot used to estimated the movement coordinations between segments. The conclusions were as follows; (1) During the support phase of walking, the elderly people generally kept their head the flexional and abductional posture. Particularly, the elderly displayed little internal/external rotation. (2) The elderly people showed extensional and external rotation postures in the trunk movement. Particularly, It showed the change from adduction into abduction at the heel contact event of the stance phase. (3) The elderly people showed almost same pelvis movement from the flexion into extension, from the abduction into adduction, and from internal rotation into external rotation at the mid stance and toe off of the stance phase.

Lower Extremities' Joint Stability during the Elderly Woman's Walking

Ryu, Ji-Seon Korean Society of Sport Biomechanics 2017 한국운동역학회지 Vol.27 No.1

Objective: The aim of this study was to investigate the periodicity of the lower extremity joint flexion/extension angle to compare the local stability between young and elderly women during walking on a treadmill. Method: Eighteen young women (mean $age=21.2{\pm}1.6y$; mean $mass=57.1{\pm}6.1kg$; mean $height=1.61{\pm}0.04m$) and 18 elderly women (mean $age=66.4{\pm}1.2y$; mean $mass=55.4{\pm}8.3kg$; mean $height=1.56{\pm}0.04m$) participated in this study. Approximate entropy (ApEn) was used to determine the periodicity in the lower limb joint angles. Results: The ApEn values of the two groups were statistically greater in the surrogate data test than in the original time series data (p<.05). The periodicity of the hip and ankle flexion/extension angles decreased in the elderly women group compared with the young women group (p<.05). The periodicity of the lower extremity joint flexion/extension angle showed that the ankle joint increased dominatingly in both groups (p<.05); the hip joint decreased compared with the knee joint in the young women group; and the knee joint decreased compared with the hip joint in the elderly women group (p<.05). Conclusion: These results suggest that the lower extremity joint flexion/extension angles of the young and elderly women during walking contained random noises as well as biological signals. In addition, the differences in the periodicity in the lower extremity joint between the young and elderly women may provide some insight in predicting potential falls and be used as a characteristic indicator for determining local stability in elderly women during walking.

Lower Extremities` Joint Stability during the Elderly Woman`s Walking

( Ji-seon Ryu ) 한국운동역학회 2017 한국운동역학회지 Vol.27 No.1

Objective: The aim of this study was to investigate the periodicity of the lower extremity joint flexion/ extension angle to compare the local stability between young and elderly women during walking on a treadmill. Method: Eighteen young women (mean age=21.2±1.6 y; mean mass=57.1±6.1 kg; mean height=1.61±0.04 m) and 18 elderly women (mean age=66.4±1.2 y; mean mass=55.4±8.3 kg; mean height=1.56±0.04 m) participated in this study. Approximate entropy (ApEn) was used to determine the periodicity in the lower limb joint angles. Results: The ApEn values of the two groups were statistically greater in the surrogate data test than in the original time series data (p<.05). The periodicity of the hip and ankle flexion/extension angles decreased in the elderly women group compared with the young women group (p<.05). The periodicity of the lower extremity joint flexion/extension angle showed that the ankle joint increased dominatingly in both groups (p<.05); the hip joint decreased compared with the knee joint in the young women group; and the knee joint decreased compared with the hip joint in the elderly women group (p<.05). Conclusion: These results suggest that the lower extremity joint flexion/extension angles of the young and elderly women during walking contained random noises as well as biological signals. In addition, the differences in the periodicity in the lower extremity joint between the young and elderly women may provide some insight in predicting potential falls and be used as a characteristic indicator for determining local stability in elderly women during walking.

Relationship between the Impact Peak Force and Lower Extremity Kinematics during Treadmill Running

Ryu, Ji-Seon,Park, Sang-Kyoon Korean Society of Sport Biomechanics 2018 한국운동역학회지 Vol.28 No.3

Objective: The aims of this study were to determine the impact peak force and kinematic variables in running speed and investigate the relationship between them. Method: Thirty-nine male heel strike runners ($mean\;age=21.7{\pm}1.6y$, $mean\;mass=72.5{\pm}8.7kg$, $mean\;height=176.6{\pm}6.1cm$) were recruited in this investigation. The impact peak forces during treadmill running were assessed, and the kinematic variables were computed using three-dimensional data collected using eight infrared cameras (Oqus 300, Qualisys, Sweden). One-way analysis of variance ANOVAwas used to investigate the influence of the running speed on the parameters, and Pearson's partial correlation was used to investigate the relationship between the impact peak force and kinematic variables. Results: The running speed affected the impact peak force, stride length, stride frequency, and kinematic variables during the stride phase and the foot angle at heel contact; however, it did not affect the ankle and knee joint angles in the sagittal plane at heel contact. No significant correlation was noted between the impact peak force and kinematic variables in constantrunning speed. Conclusion: Increasing ankle and knee joint angles at heel contact may not be related to the mechanism behind reducing the impact peak force during treadmill running at constant speed.

Effects of Prolonged Running-Induced Fatigue on the Periodicity of Shank-Foot Segment Coupling and Free Torque

Ryu, Ji-Seon Korean Society of Sport Biomechanics 2016 한국운동역학회지 Vol.26 No.3

Objective: The purpose of this study was to determine the periodicity of shank-foot segment coupling and free torque before and after fatigue induced by prolonged running. Method: Fifteen young healthy male participants with a rear-foot strike ran on instrumented dual-belt treadmills at 70% of their maximum oxygen uptake for 65 min. Kinematic and ground reaction force data were collected for 20 continuous strides at 5 and 65 min (considered the fatigued condition). The approximate entropy tool was applied to assess the periodicity of the shank internal-external rotation, foot inversion-eversion, shank-foot segment coupling, and free torque for the two running conditions. Results: The periodicity of all studied parameters, except foot inversion-eversion, decreased after 65 min of running (fatigued condition) for 80% of the participants in this study. Furthermore, 60% of the participants showed similarities in the change of periodicity pattern in shank internal-external rotation, coupling, and free torque. Conclusion: The findings indicated that the foot inversion-eversion motion may pose a higher risk of injury than the shank internal-external rotation, coupling, and free torque in the fatigued condition during prolonged running.