An Electromyographic Study on Development of Kicking Pattern in Children

本研究旨在探讨儿童踢球的发展过程。11名年龄从1岁8个月到5岁的儿童的肌电活动和形式在五年多的时间里被纵向记录，另外55名受试者被横截面记录。此外，另外580名受试者，包括1到13岁的儿童、成年人和足球运动员，通过特殊的电子设备测量了球的速度。球速随年龄增长而增加，1岁男生为1.86米/秒，13岁男生为18.29米/秒，13岁女生为12.90米/秒。1岁和2岁的儿童在撞击前的整个时期，股直肌、股内侧肌和腹直肌的电活动都很弱。在3~4岁阶段，踢腿前摆时股内侧肌有较强的放电，但接触前放电较弱。这表明孩子们不能有效地使用伸膝踢腿。在5~6岁阶段，腿摆动的总弧度显著增加，并出现代偿性手臂运动。在踢腿的前摆动作中，腹直肌表现出强烈的爆裂性。在7~8岁阶段，股内侧肌强放电由球接触后转移到球接触前。在10岁以后，男孩的膝关节、臀部、躯干和肩部肌肉的放电模式以及踢腿形式显示出与成人几乎相同的模式。然而，人们不能从肌肉活动的角度来识别踝关节的固定。从以上结果来看，学习踢腿的最佳年龄可能存在于9-13岁之间，此时儿童的身体平衡和球速接近成人水平。

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.