Society in the 19th and 20th centuries has seen the Industrial Revolution and the changing in mode of production and system of war. These changes have required a more docile body, suitable health and coordinated motion. All of these factors have been looked as human resources or marchandise. Physical education has played an important role in standardization of the individual person, because there were a conviction that a measurable fact shouldn't be doubted by every particuler sense. It has been considered as normal that the sense is negligible in scientific speculation. Thus, education as a whole has been directed at the integration of high-quality man-power into society. I assert that, since physical education has contributed to creating an ideal type of figure and performance, we are still now impelling our body, health and motion to being with non-defective animality and symmetrical conduct.

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A study was conducted to examine how kinetic factors influence ball speed following a tennis forehand drive. The subjects were 15 male college tennis players, gripping the racket with their right hand. The players performed the forehand drive with maximum effort while aiming at a target area. The trials were filmed at 100 fps using two 16-mm movie cameras. Using Winter's method, the joint torque was determined two dimensionally on the horizontal plane for the wrist, elbow and shoulder joints, and for upper torso rotation during the stroke. The subjects were divided into two groups; a fast group (n=8) and a slow group (n=7) based on the ball speed. Despite a significant difference in ball speed between the two groups, no significant differences were observed in any items related to physique, muscle strength or pewer. The positive joint torque of the shoulder joint appeared from the first stage of the stroke, that of the elbow joint from the middle stagge, while that of the wrist joint appeared at the end of the stroke. The integrated positive joint torques (IT+) during forward swing were found to be the greatest in shoulder joint and the least in the wrist joint. The IT+ were significantly different between the fast and slow groups in all joint movements except for upper torso rotation. Individual ball speeds delivered by all subjects were positively correlated with the IT+ of the shoulder and elbow joints. From these results, it was concluded that (1) individual ball speeds are influenced considerably by the shoulder and elbow joint torques in the horizontal plane, and (2) players showing faster ball speed develop greater torques in all upper limb joint movements.

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An attempt was made to investigate three-dimensional box reation forces applied to the pole-tipduring pole vaulting, and to idenfify technical factors necessary for increasing the maximal height of center of gravity (C.G.) based on the pole-chord reaction forces (henceforth, PCF). The subjects (five pole vaulters and four decathletes) performed pole vaults to clear the cross bar set at a height of 82-93% of their personal best record. All trials were videotaped with four video cameras (60 fps), and box reaction forces (500Hz) were measured with a Kistler force platform on which a specially made vaulting box was bolted. Three-dimensional coordinates of points on the vaulting poles and body landmarks of vaulters were obtained using a DLT procedure. Impulse and PCF were calculated from the forces and coordinate data. Force exerted via the lower hand (henceforth, F_<Ly>) was calculated by solving equations of motion for the pole segment between the hands. For simplicity, the mass and moment of inertia of the pole segment were assumed to be zero. The horizontal impulse of box reaction forces in the pole-bending phase and verticalimpulse in the pole-straightening phase were significantly related to the maximal C.G.height (r=-0.701, p<0.05 and r=0.688, p<0.05, respectively). These impulses were significantly related to the PCF in each vaulting phase (r=-0.888, p<0.01 and r=0.981, p<0.001, respectively). Three PCF patterns were found: Type A, in which PCF during the pole-straightening phase exceeded that during the pole-bending phase; Type B, in which the pattern of Type A was reversed; Type C, in which the PCFs during both phases were almost equal. It has been suggested by some researchers that bending and straightening moments applied to the pole by F_<Ly> influence the magnitude of pole-bending and the PCF. Type A subjects exerted F_<Ly> in a pushing direction (applied bending moment) during the pole-bending phase, and in a pulling direction (applied straightening moment) during the pole-straightening phase. The lower hand technique shown in Type A seemed more appropriate for increasing the maximal C.G. height, because (1) the vaulter was able to use a higher grip height due to the increased magnitude of pole-bending, and (2) the vertical impulse of the box reaction force was increased due to enhancement of PCF in the pole-straightening phase.

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