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

头部与池底部的碰撞是游泳中跳水动作失败的结果。它经常发展成为瞬间影响死亡致残生命的事故。关于这些产生原因和案例的报道已经做了很多。然而，很少有报道表明对生物体的损害和影响的程度。这项研究使用了人体和假人。假设日本的学校游泳池设施，测量了水碰撞底部的冲击力。此外，本研究还研究了游泳起跑时的运动模式，考察了身体各部位的运动对运动模式变化的影响。采用高速VTR系统，对游泳起跑动作中的飞行动作进行了22个类别的评价。一般池底碰撞的接触时间在0.02秒以内。设置发射条件使假头与测力板发生剧烈碰撞时，测得最大冲力11907N，最大冲击加速度113G。显然，即使建造了缓冲材料，减少了冲击的量，损害也是相当严重的。通过运动模式分析，得到以下结果：1)起跳动作呈现出一个大体的发展过程，即从跳跃模式到撞腹模式，再到跳水模式。2)对于躯干倾斜度，飞行对进入的影响大于设定位置。3)在入口保持箱子直立的孩子向上推出积木块，缩短了飞行距离。4)确定了在飞行过程中前后伸展四肢是形成起跑动作的必要条件。在入水时，肩关节的弯曲和点头似乎是从撞腹到跳水的转变所必需的。根据这些结果，我们制作了安全跳入水中的教学手册。少

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