Ishida Kazuyuki, Murata Masahiro, Hirano Yuichi
Yomiuri Giants Corporation, Tokyo, Japan.
Sports Biomech. 2006 Jul;5(2):183-96. doi: 10.1080/14763140608522873.
In this study we compared the kinematic features of the throwing motion between young baseball players of different age groups. Forty-four Japanese baseball players aged 6.1 to 12.3 years who regularly played baseball, including pitchers and position players, had their throwing actions analyzed three-dimensionally using high speed videography. Of this sample, 26 players aged above 9 years of age were categorized as the senior group, while the remaining 18 were categorized as the junior group. Senior group throwers had greater height and body mass, and produced a greater ball speed than junior group throwers. The throwing arm movement of senior group throwers was similar to that of adult skilled players. However, in the junior group throwers, the shoulder horizontal adduction angle was larger during the arm acceleration phase, and the maximum angular velocities of elbow extension and shoulder internal rotation occurred later than in senior group throwers. These results indicate that players aged above 9 years can acquire a mature throwing arm movement, while players younger than that will use an immature motion. A possible reason why these differences were shown is that the official baseball is relatively heavy for junior group throwers; they would be better advised to use a lighter ball in throwing practice.
在本研究中，我们比较了不同年龄组年轻棒球运动员投球动作的运动学特征。44名年龄在6.1至12.3岁之间、经常打棒球的日本棒球运动员，包括投手和内野手，使用高速摄像技术对他们的投球动作进行了三维分析。在这个样本中，26名9岁以上的球员被归类为高级组，其余18名被归类为初级组。高级组投手的身高和体重更高，投球速度也比初级组投手更快。高级组投手的投掷手臂动作与成年熟练球员相似。然而，在初级组投手中，手臂加速阶段肩部水平内收角度更大，肘部伸展和肩部内旋的最大角速度出现的时间比高级组投手晚。这些结果表明，9岁以上的球员可以获得成熟的投掷手臂动作，而9岁以下的球员则会使用不成熟的动作。出现这些差异的一个可能原因是，官方棒球对初级组投手来说相对较重；建议他们在投球练习中使用较轻的球。
