2004 Fiscal Year Final Research Report Summary
Larger Ball's Effect on the Shock Vibrations at the Wrist Joint of a player during the Tennis Impact with Experiment and Simulation
| Project/Area Number |
15560204
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Dynamics/Control
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| Research Institution | Saitama Institute of Technology |
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Principal Investigator |
KAWAZOE Yoshihiko Saitama Institute of Technology, Engineering, Professor (00102898)
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| Co-Investigator(Kenkyū-buntansha) |
KANAYA Keiji Saitama Inst. Tech., Engineering, part-time lecturer (90161166)
TOMOSUE Ryoso Saitama Institute of Technology, Yasuda Women's College, Human Science, Professor (50320031)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Tennis / Sports Engineering / Larger Ball / Impact / Tennis Racket / Shock Vibrations / Feel / Tennis Elbow |
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| Research Abstract |
A recent rule change by the ITF has allowed larger balls (7- 8% increase in diameter while keeping the same mass) to be used in tournaments. The intention of introducing the larger ball is to slow down the flight through the air thus reducing the dominance of the 'big-servers' on fast surfaces such as grass. A previous paper of the authors investigated the effect of the larger ball on the impact shock vibrations at the player's wrist joint and the racket handle during the forehand ground stroke and at the player's elbow joint during the service stroke by recording the waveforms of accelerations. This result showed that the waveforms of shock vibrations with the normal ball and the larger ball are very similar. Since the drag force of the larger ball is larger than that of the normal ball, the shock vibrations of a larger ball should be smaller. This paper has predicted the waveforms of shock vibrations at the wrist joint with the new large ball compared to the conventional ball during forehand stroke. The simulated results agree well with experimental results. The contact time of the larger ball is slightly longer and the impact force is slightly smaller. There is little difference in the deformation of the string and the ball between the larger ball and the normal ball.
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