脚伸展パワーが走幅跳びに及ぼす影響 : 小学5年生の場合

The purposes of this study were to clarify the effect of leg extension power on running long jump on school children, and to examine the effectivenesses of jump from shorter approach run. The experiment was composed of filming take-off movement and measuring leg extension power. In the filming, two kinds of jump were done ; longer approach run defined as Trial I (over 20 meters) and shorter approach run defined as Trial II (within 15 meters) .Subjects were thirty-four males and thirty-two females in the fifth grade of elementary school. Then, they were divided into three groups judging from relative leg extension power (leg extension power/body weight) ; Excellent group, Medium group and Poor group.Obtained variables from film analysis such as displacement, time, velocity and angle were compared among three groups. In the same way, those variables were compared between both trials. Results were as follows : 1) In the male\u27s Trial I, Excellent group recorded longer jumping distance than the other two groups as a result of higher approach running velocity. Moreover, Excellent group seemed to perform more rational take-off movement than Poor group judging from shorter contact time. 2) In male\u27s Trial II, Excellent group moved into take-off with higher approach running velocity, and showed higher initial velocity at take-off. Consequently Excellent group recorded longer jumping distance. 3) In both trials of females, there were no variables to be recognized as significant differences among groups. Therefore, running long jump of the fifth grade of females seemed not to be affected by leg extension power remarkably. 4) In the Trial II , males recorded shorter jumping distance as a result of lower initial velocity, and showed no rational take-off movements. Therefore, there were few merits by utilizing shorter approach run. 5) It was concluded that jumping from shorter approach run was effective for female\u27s Poor group because of leading better landing to sandpit without reducing velocity at take-off