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KMID : 1023920110130010021
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Journal of the Korean Academy of Kinesiology
2011 Volume.13 No. 1 p.21 ~ p.31
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Kinematic Analysis of O’Brien Style in Shot-putting Motion
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Moon Song-Hee
Kim Jin-Hyun
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Abstract
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[INTRODUCTION] The purpose of this study was to determine the effective form of O’Brien style in shot put.
[METHOD] The form was analyzed through 3 phases of the O’Brien style: reverse, gliding, and Putting. The subjects consisted of national representive athlete (n=1) and high school athlete(n=3). The experimental method of O’Brien style of Shot-putting Motion was cinematography(3D) and analyzed with Kwon3D motion analysis system. SPSS12.0 Statistics
Program was used to carry out the independent t-test, and the significance level was set at p<.05.
[RESULT] The duration of each phase was in order of gliding> Putting> reverse. In the gliding phase, the elite shot-putter performed an acting force as long as possible to maximize force and stride length. Analysis of horizontal velocity showed that the elite shot-putter was slower in the gliding phase and faster in the Putting phase than the high school shot-putters. With respect to vertical velocity, the elite shot-putter was slower than the high school shot-putters during the reverse and gliding phases. As a result of both horizontal and vertical kinematics, the
elite shot-putter’s COG was lower in the reverse and gliding phase but higher in the Putting phase when compared to the high school shot-putters. Analysis of the angular kinematic variable of the limbs showed statistically significant differences. In the gliding phase, the elite shot-putter maintained a smaller angle in R-hip, R-knee and R-ankle. Analysis throughout all three phases of O’Brien style showed that the elite shot-putter used a great range of motion(ROM) in R-elbow and R-shoulder. Analysis of the angular kinematic variable of the trunk showed statistically significant difference. When measuring the tilted angle of the trunk in the coronal plane, amateur shot-putters used a greater ROM throughout the 3 phases of O’Brien style.
[CONCLUSION] The effective form in shot put of O’Brien style will be desirable that stride length must be maintained 1:2 ratio in right and left leg during gliding phase, COG height be maintained lower height, be gradually increase knee angle and be faster extension of upper arm with forwarding the trunk.
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KEYWORD
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O’Brien style, Shot-putter, Gliding, Putting, Reverse
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