The Effect of Different Stiffness and Balance Point on Badminton Racket’s Swing Velocity and Ball Velocity

• Main Authors: Lin, Ya-Han, 林雅涵
• Other Authors: Shiang, Tzyy-Yuang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/75219565668238260856

碩士 === 國立臺灣師範大學 === 運動科學研究所 === 98 === Purpose ：To understand the effect of four different kinds of stiffness and three different swing-weight on swing-velocity, ball-velocity and coefficient of restitution. The result of the study will be taken as index to the selection and design of badminton racket in the future. Methods: Two experiments were conducted in the study; In the first experiment, the ball was served and then collided the racket; in the second experiment, the ball is fastened with clamping, hanging in the air, and hit by players. The results were recorded by 10000 Hz high speed video camera, and analyzed by video analysis software, which helped researcher to compare swing velocity and ball velocity between pre-test and post-test. Statistical analysis were conducted by two-way ANOVA to examine the effects of stiffness and swing-weight on swing-velocity, ball-velocity and coefficient of restitution. The significant level was set at α<.05. Results: In the group impacted by server, the coefficient of restitution was in direct proportion to impact velocity, and the coefficient of restitution of middle swing weight was significantly higher than that of low swing weight. In the group hit by player, the swing velocity was in reverse proportion to swing weight, and the swing velocity of low swing weight was significantly faster than that of middle swing weight. Ball velocity was effected by the stiffness of the racket when swing velocity exceed 90 km; the Swing Velocity of high swing weight is slow, but its COR was higher than those of low swing weight and middle swing weight. Conclusion: The swing weight that significantly impacted on swing velocity, ball velocity and COR, and the influence of stiffness is comparatively less than swing weight. The users and designers would be advised to choose the racket with low swing weight in order to increase swing velocity, or high swing weight in order to increase COR.