• 한국운동역학회지
• /
• 제33권4호
• /
• pp.155-163
• /
• 2023

Objective: The purpose of this study is to identify the difference in the quality of muscle contraction and kick movements according to the presence or absence of back pain in body kick movements of mixed martial arts athletes. Method: In this study, four athletes (32.75 ± 4.79 yrs, 172.50 ± 5.20 cm, 77.73 ± 13.28 kg) who have suffered chronic back pain for more than three months and scored 12 points in the Korean version of ODI. Four painless athletes (33.50 ± 4.04 yrs, 174.25 ± 3.10 cm, 83.50 ± 10.21 kg) participated. Results: During the body kick operation, the pain group had significantly higher muscle activity in the right Transversus abdominis and right Rectus femoris compared to the normal group (p<.05). In the rectus abdominis, the muscle activity was significantly lower than that of the normal group (p<.05). Also, the pain group has a higher toe speed than the normal group Significantly slow (p<.05), there was a delay in contraction of the Transversus abdominis. Conclusion: The results of this study suggest that chronic pain in the lumbar spine degrades the core's function, resulting in inefficient coordination such as Transversus abdominis contraction delay and Transversus abdominis and Rectus femoris excessive activation to compensate for it.

• 한국운동역학회지
• /
• 제24권4호
• /
• pp.367-373
• /
• 2014

Most athletes execute rhythmic hop as a preparatory motion in Taekwondo sparring. The purpose of this study was to investigate the effect of rhythmic hop on the response times and kicking velocities of Taekwondo kicks. Twelve male elite Taekwondo athletes performed a roundhouse kick and a back kick as fast as possible immediately after seeing an external stimulus in rhythmic hop and in no hop, respectively. The three-dimensional marker data of the whole body were measured at sampling rate of 200 Hz. Paired t-tests were used to compare dependent measures between hop and no hop conditions. Results indicated that the rhythmic hop did not affect response time statistically but improved the kicking velocity significantly than no hop did. Different instants of detecting an external stimulus in rhythmic hop for the back kick showed significantly different response times. Conclusively, rhythmic hop is recommendable for the purpose of kicking velocity, but not for the purpose of response time. Athletes should be careful in executing rhythmic hop as their preparatory motions for the back kick, since the response time could be shortened or lengthened according to the instant of detecting an external stimulus.

• 한국운동역학회지
• /
• 제15권1호
• /
• pp.29-44
• /
• 2005

The purpose of this study is to reveal the effects of two different kicks, the drop kick and the punt kick, into the kicking motion, through the kinetic comparative analysis of the kicking motion, which is conducted when one kicks a soccer goal. To grasp kinetic changing factors, which is performed by individual's each body segment, I connected kicking motions, which were analyzed by a two dimension co-ordination, into the personal computer to concrete the digits of it and smoothed by 10Hz. Using the smoothed data, I found a needed kinematical data by inputting an analytical program into the computer. The result of comparative analysis of two kicking motions can be summarized as below. 1. There was not a big difference between the time of the loading phase and the time of the swing phase, which can affect the exact impact and the angle of balls aviation direction. 2. The two kicks were not affected the timing and the velocity of the kicking leg's segment. 3. In the goal kick motion, the maximum velocity timing of the kicking leg's lower segment showed the following orders: the thigh(-0.06sec), the lower leg(-0.05sec), the foot(-0.018sec) in the drop kick, and the thigh(-0.06sec), the lower leg(-0.05sec), the foot(-0.015sec) in the punt kick. It showed that whipping motion increases the velocity of the foot at the time of impact. 4. At the time of impact, there was not a significant difference in the supporting leg's knee and ankle. When one does the punt kick, the subject spreads out his hip joint more at the time of impact. 5. When the impact performed, kicking leg's every segment was similar. Because the height of the ball is higher in the punt kick than in the drop kick, the subject has to stretch the knees more when he kicks a ball, so there is a significant affect on the angle and the distance of the ball's flying. 6. When one performs the drop kick, the stride is 0.02m shorter than the punt kick, and the ratio of height of the drop kick is 0.05 smaller than the punt kick. This difference greatly affects the center of the ball, the supporting leg's location, and the location of the center of gravity with the center of the ball at the time of impact. 7. Right before the moment of the impact, the center of gravity was located from the center of the ball, the height of the drop kick was 0.67m ratio of height was 0.37, and the height of the punt kick was 0.65m ratio of height was 0.36. The drop kick was located more to the back 0.21m ratio of height was 0.12, the punt kick was located more to the back 0.28m ratio of height was 0.16. 8. There was not a significant difference in the absolute angle of incidence and the maximum distance, but the absolute velocity of incidence showed a significant difference. This difference is caused from that whether players have the time to perform of not; the drop kick is used when the players have time to perform, and punt kick is used when the players launch a shifting attack. 9. The surface reaction force of the supporting leg had some relation with the approaching angle. Vertical reaction force (Fz) showed some differences in the two movements(p<0.05). The maximum force of the right and left surface reaction force (Fx) didn't have much differences (p<0.05), but it showed the tendency that the maximum force occurs before the peak force of the front and back surface (Fy) occurs.

• Journal of Chest Surgery
• /
• 제48권4호
• /
• pp.281-284
• /
• 2015

We present the case of a 38-year-old woman admitted to our outpatient clinic with accelerating back pain and fatigue following a kick to her back by her husband. Upon arrival, we detected ST segment elevation in the D1, aVL, and V2 leads and accelerated idioventricular rhythm. She had pallor and hypotension consistent with cardiogenic shock. We immediately performed coronary angiography and found a long dissection starting from the mid-left main coronary artery and progressing into the mid-left anterior descending (LAD) and circumflex arteries. She was then transferred to the operating room for surgery. A saphenous vein was grafted to the distal LAD. Since the patient was hypotensive under noradrenaline and dopamine infusions, she was transferred to the cardiovascular surgery intensive care unit on an extracorporeal membrane oxygenator and intra-aortic balloon pump. During follow-up, her blood pressure remained low, at approximately 60/40 mmHg, despite aggressive inotropic and mechanical support. On the second postoperative day, asystole and cardiovascular arrest quickly developed, and despite aggressive cardiopulmonary resuscitation, she died.

• 한국응용과학기술학회지
• /
• 제37권4호
• /
• pp.870-877
• /
• 2020

본 연구의 목적은 제자리딛기 템포와 돌려차기 유형이 응답시간에 미치는 영향을 비교 분석하는데 있다. 본 연구에는 태권도 4단이며 10년 이상 수련한 남자 15명이 참여하였다. 실험 과제는 메트로놈의 템포에 맞춰 제자리딛기를 하다가 불빛 자극이 제시되면 최대한 빠르게 돌려차기를 하는 것이다. 5가지의 제자리딛기 템포(100, 120, 140, 160, 180 bpm)와 4가지의 돌려차기 유형(앞발 몸통 돌려차기, 앞발 얼굴 돌려차기, 뒷발 몸통 돌려차기, 뒷발 얼굴 돌려차기)에서 3회씩 총 60회를 실시하였다. 통계분석은 반복 측정 이원분산분석을 실시하였으며, 주효과의 대응별 비교는 Bonferroni를 실시하였다. 제자리딛기 템포와 돌려차기 유형의 상호작용효과가 나타났으며, 제자리딛기 템포와 돌려차기 유형에 따른 주효과도 나타났다. 160 bpm의 제자리딛기 템포에서 돌려차기의 응답시간이 제일 빠른 것으로 나타났다. 하지만 140과 160 bpm의 제자리딛기 템포에서 돌려차기 응답시간은 거의 차이가 나타나지 않았다. 앞발 몸통 돌려차기의 응답시간이 빨랐다. 그리고 제자리딛기 템포와 돌려차기 유형에 따라 140 bpm의 제자리딛기 템포에서 앞발 몸통 돌려차기의 응답시간이 가장 빠른 것으로 나타났다. 결론적으로 돌려차기의 응답시간은 140과 160 bpm의 제자리딛기 템포에서 효과적이며, 뒷발보다는 앞발, 얼굴보다는 몸통 돌려차기가 효과적인 것으로 나타났다. 본 연구를 통해 도출된 결과는 수행 향상에 유용한 정보를 제공할 것이며, 태권도 경기를 위한 전략에 도움이 될 것이다.

• 한국운동역학회지
• /
• 제18권1호
• /
• pp.117-127
• /
• 2008

본 연구는 개발된 태권도화에 따른 태권도 돌려차기와 몸돌려 후려차기시 기계적 마찰력과 태권도 수행력에 대하여 연구하는데 목적이 있다. 본 연구를 위하여 A.F.T.S.(Automated Footwear Testing System)과 태권도 수행력 테스트를 실시하였으며 착화감에 대한 설문을 조사하였다. 본 실험의 결과 태권도화 종류에 따라 기계적 마찰력은 유의한 차이를 보였으며, 돌려차기시 최대 자유모멘트의 통계 결과값은 p=.011 이었고, 최대 족저압에 있어서 타입 A 태권도화와 타입 B 태권도화도 사이에 있어 유의한 차이를 보였다. 착화감 설문 결과 5가지 항목에 있어 타입 A와 타입 B 태권도 사이에 있어 유의한 차이를 보였지만 타입 B와 타입 C 태권도화에 있어서는 모든 항목에서 유의한 차이를 보이지 않았다. 태권도화별 기계적 마찰력에서 유의한 차이를 보인 반면 수행력에 있어서는 영향을 미치지 못하는 것으로 판단되며, 설문 결과와 수행력 사이에 있어서도 관계가 없는 것으로 나타났다. 본 연구를 통하여 임상 실험 결과와 기계적 마찰력 정도가 태권도 수행에 영향을 주는지 여부와 훈련 시 부상 방지 및 수행력을 향상시키는 태권도화의 생체역학적 설계 및 현 개발 시제품에 대한 후속제품개발에 도움을 주고자 한다.

• 대한기계학회논문집A
• /
• 제32권1호
• /
• pp.83-90
• /
• 2008

Taekwondo is a martial art form and sport that uses the hands and foot for attack and defense. Taekwondo basic motion is composed of the breaking, competition and poomsea motion. In the side kick among the competition motion, the impact force is larger than other kinds of kicks. The side kick with the front foot can be made in two steps. In the first step, the front foot is stretched forward from back stance free-fighting position. For the second step, the rear foot is followed simultaneously. Then, the kick is executed while entire body weight rests on the rear foot. In this paper, impact analysis of the human model for hitting posture is carried out. The ADAMS/LifeMOD is used in hitting modeling and simulation. The simulation model creates the human model to hit the opponent. As the results, the dynamic analysis of human muscle were presented.

• 한국운동역학회지
• /
• 제21권1호
• /
• pp.57-65
• /
• 2011

This research was conducted to biomechanically analyze Tippelt motion in parallel bars, and establish technical understanding. To achieve that goal, the performances of the Tippelt acts carried out by five world top-class national gymnasts in the parallel bars 3-dimensional cinematographic analysis and EMG analysis were conducted and following conclusion were obtained. The Tippelt motions of excellent national gymnasts perform tap motion through the down swing of a large circular movements, and perform kick-out motion rapidly extending shoulder joint angle and hip joint angle with the trunk in a position close to perpendicular position at the vertical downwardness of the grasping the bars. At this time, if handstand starting the movement is too delayed or rapidly down swung, it was shown that from the initial falling, unnecessary muscular power was wasted in trapezius, anterior deltoid, erector spinae, latissimus dorsi, upper rectus abdominis, lower rectus abdominis. The muscular parts in tap motion generating muscle action potential were pectoralis major, rectus femoris, upper rectus abdominis, lower rectus abdominis, and those in kick-out motion were upper rectus abdominis, lower rectus abdominis, trapezius and anterior deltoid.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제27권7호
• /
• pp.712-722
• /
• 2000

본 논문은 팀 스포츠(team sports)의 일종인 축구경기 하이라이트 장면의 자동색인을 위해 뉴럴네트워크 기법을 이용하여 그룹 포메이션(group formation) 중의 공격패턴 자동분류 기법을 개발하고 이를 검증하였다. 본 연구에서는 축구경기의 대표 프레임 상에서 선수들과 공의 위치정보를 추출하고 그룹 포메이션 정보를 기초로 뉴럴네트워크의 BP(Back-propagation) 알고리즘을 사용하여 축구경기 하이라이트 장면의 자동추출을 위한 공격패턴 자동분류 기법을 개발 및 검증하였다. 또한, 실험에는 ‘98 프랑스 월드컵 축구경기의 다양한 공격패턴에 대한 비디오 영상에서 각각 좌측공격 60개, 우측공격 74개, 중앙공격 72, 코너킥 39, 프리킥 52개의 총 297 개의 데이타를 추출하여 사용하였다. 실험결과는 좌측공격 91.7%, 우측공격 100%, 중앙공격 87.5%. 코너킥 97.4%, 프리킥 75% 로서 매우 양호한 인식율을 보였다.

• 한국운동역학회지
• /
• 제16권3호
• /
• pp.43-51
• /
• 2006

The purpose of this study was to analyze kinematic variables during turing back kick motion of Taekwondo. The subjects of this study were the 4 skilled and 4 unskilled of male university player in respectively. The experiment of this study was used two 16mm high speed cameras and its speed 125 frames/s. Analysis of this data was three dimensional cinematography using KWON3D program package. The results were as following; 1. In the elapsed time, there was no significance difference statically between a skilled and unskilled group. But skilled group was more fast during the motion of I phase. And unskilled group was more fast during the motion of II phase so called force production section, which had an influence on Diechagi's velocity. 2. In the center of gravity of human body, the changing of it was $1.10{\pm}0.04m$, $1.12{\pm}0.03m$ of LFM(left foot movement) and $1.36{\pm}0.08m$, $1.39{\pm}0.09m$ of RKF(right knee flection), and $1.44{\pm}0.08m$, $1.42{\pm}0.09m$ of RFI(right foot impact). There was no significance difference statically between the two groups. 3. The velocity of heel on impact was 1.13m/s in the skilled group and 1.23m/s in the unskilled group, when each angle of knee was $110.4{\pm}10.9deg/s$, $114.8{\pm}28.4deg/s$. The maximum velocity of each performance was reached before the RKF, and the velocity and angle at impact along by two groups did not show any significant difference statically. 4. In the angular velocity of just RKF of lower leg, there was significance difference statically between the two groups(p<.05).