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KMID : 1023920130150010087
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Journal of the Korean Academy of Kinesiology
2013 Volume.15 No. 1 p.87 ~ p.95
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Effects of Tennis Racket Frame Size and String Tension on the Change of Ball Speed and Tennis Racket Movement during Impact
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Lee Jeong-Myung
Kwak Chang-Soo
Jeon Min-Ju
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Abstract
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Introduction: The purpose of this study was to determine optimal string tension of tennis racket size through analyzing ball speed, motion of tennis racket head, relationship between ball and string tension with different racket frame sizes and string tensions.
Method: The tennis racket sizes used for this study were Mid-sized and Over-sized two different rackets made by Prince Company. Four different string tensions were 55lb, 60lb, 65lb, 70lb. Ball speed, ball compression, ball contact time, displacement of racket head, vibration were measured and analyzed by using 16mm high speed cine camera and ball project machine.
Result: The ratio of tennis ball speed after impact was decreased with increment of string tension, but there no significant differences between Mid-sized and Over-sized tennis racket. The displacement of Over-sized tennis racket at impact was larger than Mid-sized tennis racket(p<0.01), and the displacement of racket head was decreased with increment of string tension. The ball compression at impact was decreased with the increment of string tension, and were not affected by two racket frame sizes. The ball contact time was appeared to be short period with the increment of string tension, and were not affected by two racket frame sizes. The vibration of racket head was decreased with the increment of string tension, and were not affected by two racket frame sizes.
Conclusion: It was showed that tennis racket frame size and string tension affected tennis racket motion. The optimal string tension was 55lb below when considering the ball speed. Whreras when considering the ball control, the optimal string tension was 65lb above.
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KEYWORD
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Tennis Racket Frame Size, String Tension, Ball Contact Time, Ball Compression
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