Experimental Study of the Starting Times in Jumping at Various Stages

Abstract

In this study, the starting times and pass curves of the hip, knee and the ankle joints were recorded during jumping at various stages in standing broad jump and sarjent jump. Four subjects (who were high school athletic club member) were employed in this study. (Table I Showed) Subjects were asked to jump five different stages of distance graduated in twenty percent of their maximum performance. Every stage consisted of three sets of jumping, one set including two trials, so that fifteen sets were in order given for each jumping stages. Results obtained were as follows; 1. The starting times were rectilinearly later according to the increase of jumping stages. 2. The starting speeds were rectilinearly higher according to the increase of jumping stages. 3. The pass curve of the ankle joint formed a half gourd shaped during jumping at maximum distance. In vertical plane, the ankle joint was more eleveated during jumping at longer distance. The peak on the pass curve of the hip joint was not changed at every stages. The peak on the pass curve of the knee joint appeared right in the center between the peak on the pass curve of the hip joint and the landing point. 4. The amplitude of the rotation of the hip, knee, ankle and shoulder joints tended to increase according to the increase of jumping distance.