2001 Fiscal Year Final Research Report Summary
Motion analysis of the lower extremities generating the rotation of the trunk around its long axis in some movements.
| Project/Area Number |
12680016
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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 |
体育学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOJIMA Takeji The University of Tokyo, Graduate School of Arts and Sciences, Lecturer., 大学院・総合文化研究科, 講師 (20111437)
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| Project Period (FY) |
2000 – 2001
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| Keywords | tennis / backhand / golf / tee-shot / baseball / batting |
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| Research Abstract |
The rotation of the trunk around its long axis is important for making racket or bat or club and ball speeds large in tennis or baseball or golf. The purpose of this study was to clarify the mechanisms of the lower extremities to generate the rotation using cinematography and force platforms.
Japanese college athletes in the fields of tennis and baseball, and three professional and two amateur golf players with low handicap participated in this experiment. Single-handed or doublehanded backhand top-spin strokes of the tennis players, tee batting of the baseball players and tee shots of the golfers using a driver were filmed with a nominal film speed of 200 fps, and the force which each foot acted on the force platform was measured simultaneously.
The torques around the joints of the lower extremities during the hitting motions were determined using an inverse dynamics. Then, hip torque components which contributed to the rotation of the pelvis around its superior-inferior axis was determined.
The hip extensors of the rear-leg and the hip adductors of the fore-leg contributed to the pelvis rotation in the three hitting motions. The hip flexors of the fore-leg also contributed to the rotation in the tee batting. The hip flexors did not contributed to the rotation in the tennis backhand strokes and golf tee shots because that the tennis players had to extend their hip joint of the fore-leg to swing the racket upward for a top spin ball and that the golfers had to extend the joint to have the arms pulling the driver hard to its rotational center immediately before ball impact.
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