Mechanism of the Head Collusion Accident of Swimming Dive and Making the Manual for Safe Diving

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The head collision with the base part of the pool results from the failure of diving movement in swimming. It often develops into the accident which instantaneously affects life of die disablement. The report concerning these generation causes and cases is done a lot. However, there are few reports by which the damage to the living body and the amount of the impact become clear. This research used the human body and the dummy. The impact in the bottom of the water collision was measured supposing the school pool facilities in Japan. Moreover, this study investigated motor patterns in swimming start and examined movements of each part of body influencing the change of motor pattern. Using high-speed VTR system, the flight motions were evaluated by the scale of 22 categories in swimming-start performance.The contact time of the collision of the general pool bottom was 0.02 seconds or less. When launching condition was set so that the dummy head may violently collide with the force plate, … More maximum impulsive force 11907N and maximum impact acceleration 113G were detected. Clearly the damage is considerably serious even if the buffer material is constructed and the amount of the impact is reduced.By the motor patterns analysis, following results were obtained. 1)Starting motions showed a general process of development, which proceeded from a jumping pattern to a hitting-the-belly pattern, then to the pattern of a plunge dive. 2)Regarding inclination of the trunk, the flight had a greater influence than the set position on the entry. 3)The children who kept the trunk upright on the entry pushed off the block in an upward direction and shortened flight distance. 4)It was confirmed that stretching four limbs in front and rear during the flight was necessary to develop the starting motion. 5)On the entry, the flexion of the shoulder joint with nodding the head seemed necessary for the change from hitting the belly to the plunge dive.Standing on these results, we made the teaching manual for safe plunge entry into water. Less