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초등 학교 투수의 빠른 오버 암 피칭 동작에 대한 운동학적 분석
정철수,이건범 師範大學 體育硏究所 1996 서울大學校 體育硏究所論集 Vol.17 No.2
The purpose of this study was to provide some fundamental informations about coaching of pitching motion by analyzing 3 dimensional kinematic properties of 8 primary school pitchers's over~arm fast pitching in baseball. DLT method was adapted to analyze the film of pitching motion from set stance to release point by using two high speed cameras with 200fps. The results of this study were follow; 1. The mean velocity after release was 27.06±1.25m/s. 2. The time between the initiation of the wind up and release was 1.05±0.14 sec and the proportion of start, cocking, and acceleration phase was approximately at the five-four-one ratio. 3. The velocity change of the ankle joint of the lower limb showed that the linear velocity of the proximal joint was reached the maximal velocity just after the distal joint began to decelerate. The velocity changes of the shoulder, elbow, and the wrist joint of the throwing arm showed that the linear velocity of the distal joint were reached maximal velocity just after the proximal joint began to decelerate. The subject's time interval having fast ball between the maximal velocity of each joint and release was shorter than subject having slow ball. 4. The maximum linear velocity of the wrist was reached 0.02-0.03s before release. 5. The stride length and the height of C.G of the body at release recorded 86±3.6%, 31.0±2.55% of the pitcher's standing height. 6. The hight of the pitching ball at release recorded 78±6.3% of the pitcher's standing height and the stride length and the forward lean angle of the trunk were the main factors of it. 7. The release point recorded 15.17±7.12cm on the right, 3.02±8.90cm on the back from the center of the lead foot. The release point of the subjects who pitched the ball faster than the other was close to the center of the lead foot. 8. In the start phase, the knee height of the lead leg recorded 51.1±13%, 24.9±1.7% of the pitcher's standing height at release. 9. The angle between the shoulder line and the for-arm was 10.11±7.07。 at the maximal cocking and 16.95±12.09。 at release, respectively. 10. The forward lean angle of the trunk was 3.11±6.35。 at the maximal cocking and -29±10.08。 at release, respectively. 11. The lateral lean angle of trunk was -10.03±6.03。 at the maximal cocking and -27.44±9.78。 at release, respectively. 12. The knee joint angle of the lead leg was 119.86±8.59。 at the maximal cocking and 109.11±10.42。 at release, respectively. The hip joint angle of the lead leg was 114.82±9.98。 at the maximal cocking and 80.56±16.32。 at release, respectively. The knee and the hip joint of the lead leg were more flexed at release than at the maximal cocking phase. 13. The shoulder joint angle of the throwing arm was 90.58±13.79。 at the maximal cocking and 95.25±12.28。 at release, respectively. The elbow joint angle of the throwing arm was 122.44±12.41。 at the maximal cocking and 121.41±13.30。 at release, respectively. 14. The angle between C.G of the lead foot and the throwing direction (an inaginary line drawn from the pivot foot to home plate) was 0.2±7.6。. The striding foot moved directly toward the home plate and landed with the ball of this foot on the throwing direction.
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