| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1984: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
The purpose of this study was to examine the developmental process of the ball-kick in children. EMG activity and Form were longitudinally recorded throughout periods of over five years for eleven children ranging in age from 1 year 8 months to 5 years, and cross-sectionally recorded for anothe 55 subjects.
In addition, ball speed for another 580 subjects, including children 1 to 13 years old, adults, and soccer-players, was measured through a special electrical device.
1). Ball speed increased with the age in both sex, from 1.86m/sec for 1 year to 18.29m/sec for 13 year old boys, and to 12.90m/sec for 13 year old girls.
2). One and two year old children showed very weak electrical activity of the rectus femoris, vastus medialis, and rectus abdominis muscles throughout the period before impact.
3). At the stage of 3 to 4 years of age, the vastus medialis showed a strong discharge during the forward swing of the kicking leg, but the discharge was weaker before contact than after. This indicated that the children were not able to use the knee extension effectively for kicking.
4). At the stage of 5 to 6 years of age, the total arc of leg-swing increased significantly and a compensatory arm movement appeared. The rectus abdominis showed a strong burst during the forward swing of the kicking leg.
5). At the stage of 7 to 8 years of age, the strong discharge of the vastus medialis shifted from the period after ball contact to before.
6). Beyond 10 years of age, the discharge pattern of knee, hip, trunk, and shoulder muscles, and kicking form showed almost the same pattern in boys as in adults. However, one could not recognize fixation of the ankle joint in terms of muscle activity.
7). From the above results, the optimum time to learn the kick might be existed between 9 and 13 years of age, when children approach the adult level of body balance and of ball speed.
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