골프 스윙시 하지의 운동역학적 분석

장재관 ( Jae Kwan Chang ),류재균 ( Jae Kyun Ryu ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.4

The purpose of this study was to investigate joint torques of lower body segments on professional golfers. Three dimensional swing analysis was conducted on the seven subjects. Each subject was asked to swing with 45 inches of Callaway driver, where two force plates (9286AA, Kistler, Switzerland) were built, with his normal speed and tempo. The resultant joint moments of the lower extremities were computed using the kinematic variables of the segments, anthropometric measures and the ground reaction force data by inverse dynamics method. Based on the results of this study, the following conclusions were drawn; It was found that the left ankle joint torque at 3rd phase was increased toward extension on the X-axis and abduction on the Y-axis. The left knee joint torque was alternated from flexion to extension direction in order to lower down the body weight at the beginning of the downswing. The lumbar joint torque was alternated from flexion to extension in order to speed up the upper body rotation which could increase the club head speed ultimately

프로와 아마추어골퍼의 스윙 평면 비교연구

장재관(Chang Jae-Kwan),여홍철(Yeo Hong-Chul) 한국체육과학회 2009 한국체육과학회지 Vol.18 No.1

The purpose of this study was to investigate the planar motion of the shaft in a golf swing and any differences between professional and amateur golfers. Four subject golfers were participated and the swing motions with s driver were videotaped and analyzed using three-dimensional techniques. The results can be summarized as follows. The distance from the shaft plane to hozel at address was 0.00㎝ and was raised up at top of the back swing with 62.15㎝, 46.56㎝, 96.04㎝ and -81.98㎝ respectively. This result was contradicted what Cochran & Stobbs's asserted as the golf club head and hand did move in a single plane during a golf swing. The hozel trajectory showed a similar shape with professional golfers but not with amateurs golfers. At P7 which was the impact position the shaft angles were more steeper than the address position with three out of four subjects.

세계랭킹에 영향을 주는 골프 경기력 요인 분석

장재관(Chang Jae-Kwan),여홍철(Yeo Hong-Chul) 한국체육과학회 2008 한국체육과학회지 Vol.17 No.4

The purpose of this study was to investigate professional golfer's technical factors which influenced to the official world golf ranking. The subjects were professional golfers who were ranked within 63th in the official world golf ranking in 2007. The research assumptions were as following, First, there would be a correlation between golf's technical factors and world ranking. Second, there would be some notable differences in golf's technical factors which would effect to 5 groups differently. The results could be summarized as follows. The average driving distance was 291.20 yards and the average scoring average was 70.01. The world golf ranking had a meaningful correlation both the putt per round and scoring average. The short game ability which was putt per round and scoring average was the key factor which influenced to the official world golf ranking. The scoring average factor had a meaningful effect less than 1% in the statistics level on the official world golf ranking. Performance Statistics are unlikely to able to predict the better performers in the official world golf ranking.

골프 스윙 시 클럽 헤드의 운동에너지에 대한 신체 분절의 기여도

장재관 ( Jae Kwan Chang ),류지선 ( Ji Seon Ryu ),윤석훈 ( Suk Hoon Yoon ) 한국운동역학회 2011 한국운동역학회지 Vol.21 No.3

The purpose of this study was to investigate the contributions of body joints to the kinetic energy of the clubhead in the golf swing. Three dimensional swing analysis was conducted on the seven KPGA golfers. The subjects were asked to swing with 45 inches of driver. The work done by body joints were computed by utilizing the inverse dynamics method. The order of work done by the body joints was lumbar > left hip > right shoulder > left wrist > right wrist > right hip at the first phase. At the second phase, the order of work done by the body joints was trunk > left elbow > right wrist > right shoulder > left wrist > right wrist. At the third phase, the order of work done by body joints was lumbar > right shoulder > left shoulder > left elbow > right wrist > right elbow. The sum of the work done by the body joints was lumbar > shoulder > wrist on the average. The kinetic energy of the club head was 430.11±24.35 J and the subject`s swing efficiency was shown as 31.82±4.86% on the average. The contributions of body joints to the kinetic energy of the clubhead was the order of lumbar > upper right shoulder > left elbow > right wrist during the down swing.

골프 스윙 시 클럽헤드의 평면운동에 관한 고찰

장재관(Chang, Jae-Kwan),류재균(Ryu, Jae-Kyun) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.5

The golf swing had been investigated mathematically with least mean square error method whether the club head could be swung in a single inclined plane. The recent findings suggest that the club head trajectory did not fit exactly to a single plane but could consider its motion as a plane with minor errors. The purpose of this study was to verify whether a single plane could be fitted to club motion with singular value decomposition method. Six professional golfers were participated and the swing movements with driver were analyzed by three-dimensional analysis techniques. The results can be summarized as follows. The orthogonal distances errors from the fitted plane to the center of the club head were shown between 2.6cm and 7.2cm. By considering Cochran & Stobbs"s assertion that 30 yards driving distance reduction with 1.8m mishit from the sweet spot the average distance error from the fitted swing plane to the club head center was 4.23cm at impact and the error could lead the club head mishit the sweet spot. As a result the club head trajectories were not fitted to a single plane.

PGA 투어 선수들의 경기력 요인들이 평균타수와 상금획득에 미치는 영향

장재관(Chang, Jae-Kwan) 한국체육과학회 2014 한국체육과학회지 Vol.23 No.3

The purpose of this study was to investigate PGA professional golfer`s performance factors which influenced to the scoring average and money leader. The subjects were top one hundred eight money leaders of US PGA tour in 2013. The t-test and stepwise regression analysis of SAS 3.0 with significant (p<.05) were conducted to examine eight PGA professional golfer`s performance factors. The results could be summarized as follows. The PGA group players showed better performance in scoring average and money earning. The PGA group was influenced by sand save percentage, stroke gained in putting and driving accuracy while the WEB.com group was influenced by green in regulation, scrambling and money leader on scoring average. The PGA group was influenced by scoring average and stroke gained in putting while the WEB.com group was influenced by scoring average, green in regulation and scrambling on money leader.

다운 스윙시 프로골프 선수들의 스윙평면에 관한 고찰

장재관(Chang, Jae-Kwan),류재균(Ryu, Jae-Kyun) 한국체육과학회 2014 한국체육과학회지 Vol.23 No.6

The golf swing has been investigated mathematically with least mean square error method whether the club head can be swung in a single inclined plane. The recent findings suggest that the club head do not move exactly in a single plane because of the minor errors at the beginning of the downswing. The aims of this study were to verify when the club head begun to the regression plane during the downswing. Four professional golfers were participated and the swing movements with 5 iron were analyzed by three-dimensional analysis techniques. The results can be summarized as follows. The orthogonal distances from the regression plane to the center of the club head were shown between 0.055m and 0.112m above the plane at position 2. So the golf instructor"s assertion that the extended line of the shaft pointing the ball flight line at position 2 was not correct. The angles of the right elbow at the top the back swing were shown between 83.6˚ and 89.2˚ for the participants so that the golf instructor"s assertion with 90˚ at the top of the back swing was supported. The conclusion was that the motion of club head during the downswing was not fitted to a single plane.

세계 정상급 여자 허들 선수들이 사용하는 허들 넘는 기술의 운동학적 분석

류재균 ( Jae Kyun Ryu ),장재관 ( Jae Kwan Chang ) 한국운동역학회 2011 한국운동역학회지 Vol.21 No.2

The purpose of this study was to evaluate the kinematic characteristics of 5th hurdle clearance during the 100m hurdle final competition at the 2010 Colorful DaeGu pre-championship meeting. This study was also intended to provide the technical data for better performance for preparing the 2011 world championship. Lee and Jung need to change technical movement by reducing the distance of the take-off point from the hurdle and by decreasing the vertical velocity of the C.G.(center of gravity) at the takeoff. Powell`s angle of the take-off leg showed bigger at the touchdown and smaller at the takeoff comparing to Lee`s and Jung`s. Furthermore, Powell`s horizontal velocity of the C.G. was maintained at the takeoff and touchdown. So, Lee and Jung need to change angle of the take-off leg the same as Powell`s. Both Lee and Jung need to increase the angle of landing leg at the touchdown. In addition to increasing the angle Jung needs to improve the knee and ankle velocity with the hurdling leg.

세계 정상급 멀리뛰기 선수들의 도움닫기, 발구름 동작과 에너지 변환에 관한 연구

류재균 ( Jae Kyun Ryu1 ),송주호 ( Joo Ho Song ),장재관 ( Jae Kwan Chang ),김혜영 ( Hye Young Kim ) 한국스포츠정책과학원(구 한국스포츠개발원) 2012 체육과학연구 Vol.23 No.4

이 연구는 도움닫기 마지막 세 스트라이드 및 발구름 동작에서 일어나는 동작 변화를 세 개의 운동면에서 분석하고 발구름 구간에서의 에너지 흐름의 특성을 분석하는 것이다. 이 연구는 2011년 대구세계육상선수권대회에서 남자 멀리뛰기 결승에 진출한 선수들 중 1위에서 8위에 입상한 선수들을 대상으로 5대의 Sony 비디오 카메라를 사용하여 60Hz로 선수들의 운동장면을 촬영하였으며 Kwon3d 프로그램을 이용하여 운동학적 자료를 산출하였다. 또한 에너지 흐름의 특성을 분석하기 위하여 에너지 변환지수와 에너지 전환효율을 계산하였다. 분석 결과 다음과 같은 결론을 얻었다. 도움닫기 마지막 세 스트라이드의 보폭 변화는 전형적인 멀리뛰기 보폭 변화인 보통-길고-짧게 하는 보폭 패턴을 보였으며, 스트라이드 각은 페널티메이트에서 모든 선수들의 스트라이드 각이 크게 나타났다. 수평면에 투영한 도약각도는 이륙순간 좌우속도에 따라 구름판 이륙시점에서 우측 혹은 좌측으로 도약각이 결정되는 것으로 나타났다. 전후면에서 접지순간 다리의 각도가 작을 경우에는 구름판에서 수평속도의 제동이 되는 것으로 나타났다. 이륙순간 다리의 각도가 작게 되면 도약각도는 클 수 있으나 구름판에서 발구름 동작으로 인한 수평속도의 추진력이 떨어지는 것으로 나타났다. 좌우면에서 이륙순간 다리의 각도는 접지에서 이륙순간으로 진행되면서 발구름 다리의 각도가 서로 교차되는 것으로 나타났다. 에너지 변환지수는 경기력이 우수한 선수일수록 높게 나타났으나 Watt 선수처럼 도약각이나 구름판 이륙순간 수평속도의 감속이 크면 작게 나타났다. 에너지 전환효율은 선수들간에 큰 차이를 보이지 않았지만 구름판 이륙순간에서 수평속도의 감속이 크고 수직속도가 크게 증가되면 높게 나타났다. The purpose of this study is to reseach the kinematic variables of the last three strides on the cardinal planes and the energetic processes of take-off performance. The subject of this research were the athletes whos ranked within top eighth of the long jump competition at the 2011 Teagu world championship. Each long jump was recorded using a video camera operating at 60Hz and Kwon3D program was used to analyse the video images of the jumps and the results were as follow: 1. The stride patterns of the subjects utilized the long penultimate-short last stride strategy except Manyongga. All subject of 2nd stride angles showed higher angels. 2. The take-off angle in the horizontal plane was determined with medio-lateral velocity. If the angel of leg placement in the sagittalple was smaller the horizontal velocity decreased a lot. The angle of leg placement in the frontal plane was twiseted at the take-off phase. 3. The transformation index values were higher with the whos performed superior but lower with subject like Watt whos performed on the higher take-off angle and the higher decreased horizontal velocity at the take-off board. 4. The conversion efficiencies were not showed any differences among the subjects but were showed higher with the higher decreased horizontal velocity and increased vertical at the take-off board.

엘리트 여자 100m 허들선수들의 운동학적 변인 비교

류재균 ( Jae Kyun Ryu ),장재관 ( Jae Kwan Chang ),여홍철 ( Hong Chul Yeo ),임정우 ( Jung Woo Lim ) 한국운동역학회 2007 한국운동역학회지 Vol.17 No.4