A-23 テニスのトップスピンとアンダースピンのボール挙動におよぽすボール毛羽の影響 : 超高速ビデオ画像解析と流れの可視化(テニス・バドミントン2)

Abstract

The previous papers of the authors made clear the mechanism of top spin performance in tennis and its improvement by lubrication of string intersections according to the high speed video analysis. As the main strings stretch and slide side ways more, the ball is given more spin.due to restoring force parallel to the string face when the main strings spring back and the ball is released from the strings. Since the notches of strings decrease spin rate, the lubricant materials are effective to the notched strings. Furthermore, it was shown that the top spin rate of newly strung tennis racket without notches is much larger than that of used racket with notches in the case of the nylon strings and the natural gut. It was also shown that the more spin results in the reduction of shock vibrations of the wrist joint during impact. This paper showed the underspin behavior when a pro and an amateur hits a ball. Furthermore, it also showed the comparison of the spin behavior between a tennis ball and a smooth surface ball without felt and made clear the mechanism of ball control by using high speed video camera and flow visualization.