Abstract
Multicomponent forces were exerted and recorded electrically upon the measuring platform, on which subjects landed from standing position. These experiments were designed in four measuring conditions of landing motion and were aimed to obtain data of shock-absorbability in these activities. Experimental conditions were (1) landing posture-soft or hard motion, (2) attaching load to the body- 0, 5 or 10kg, (3) height of standing at jumping-70 or 110cm and (4) coefficient of attaching spring on the platform - 0 or 1.05kg/mm. Analyzing these recording data of multicomponent forces by the control theory, landing motions were divided into the absorbable and the non-absorbable motions for external disturbances and function of absorbability was measured and estimated quantitatively. That absorbability was assumed by the following value α=Hf/At (Hf : amplitude of max. force, At : absorbed time). When absorbable motions were shown in these landing experiments, the vertical force was composed of one phase of force peak, but on the other hand when non-absorbable motions were revealed that peak of force was made of two phase and also fore-backward and left-rightward forces were deviated from the center line of stability. Characteristics of the most absorbable landing motion were shown on the constant value of multicomponent forces in spite of many disturbances exerted from external load, height and spring. Then the length of absorbed time in absorbable force waves was marked in the oscillation of multicomponent forces and large angle of declining curves were characterized remarkedly.
