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Golf 다운스윙 시 신체 중심과 자세 변화에 관한 고찰: PGA 골퍼
장재관,류재균 한국체육학회 2022 한국체육학회지 Vol.61 No.4
The objective of this study is to evaluate qualitative analysis on the center of whole body, trunk, pelvis and hip and knee angle during the golf downswing. Each body segment’s kinematical parameters were produced by utilizing the 3-D swing motion of PGA professional golfers. The subjects of this study were two players who had experience as elite US junior golf and were active as players on the US PGA 1st Tour and Canaidan 1st Tour. The analyzed segments of the body were center of mass for head, trunk, hip and whole body. The results were as follow. First of all, The movement of segment centers were different for each player in the target, in the vertical, in the forward and backward directions. Second, subject 1 performed the downswing using hip and knee angle changes and subject 2 performed using the knee angle changes. Third, The particular differences in the movement direction of the whole body and the center of each segment depend on the lower body posture. It is judged that the movement of the lower body affects the overall downswing patterns of elite golfers.
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.
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.
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.
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.
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