Relation between Contact Position of Volleyball Spike Serve and a Ball's Trajectory |
Do-Yeop Kim, Ki-Chung Lee, Chang-Soo Kwak |
Chuncheon National University of Education Hallym University |
Correspondence:
Chang-Soo Kwak, Email: cskwak@hallym.ac.kr |
Received: 31 August 2013 • Accepted: 19 October 2013 |
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Abstract |
INTRODUCTION The purpose of this study was to investigate a ball's trajectory according to absolute and relative position of volleyball Spike serve. METHOD For that purpose relation between a ball's position and trajectory was analyzed based on the court and player at the Spike serve of four high school elite volleyball players. The followings were concluded after analyzing kinematic variables by three-dimensional images using the video of spike serve. RESULT The height of the ball in a moment of the impact of a spike serve are 273.6cm. The distance between shoulder and the ball in a moment of the impact is also 15.1cm when you succeed, but it is 32.5cm when you fail. The height of the ball is 303.7cm that is about 60cm from over the net, when the ball pass by the net. CONCLUSION It was significant to hit the ball leaving a little space about one ball between the ball and the shoulder of spike's arm and desirable that the height of the ball at the moment passing the net was 60cm. Although the height on hitting the ball have not materially affected the outcome of Spike serve the higher the hitting position was, the better angle was secured to drop the ball inside the court. Instantaneous velocity on hitting the ball showed that hitting the ball at high speed was proper to have successful Spike serve. The ball's trajectory were rapidly on the downward path from the net to the ground. Once the ball was put Topspin, the ball sharply fell down by the Magnus effect. For this reason, it was considered that hitting the top of the ball was advisable. |
Keywords:
Volleyball, Spike Serve, Contact Position, Trajectory, 3D Cinematography |
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