基于动态时间规整算法的青少年乒乓球运动员击球动作合理性评价--以反手拉上旋弧圈球为例

Rationality Evaluation of Young Table Tennis Players’ Striking Action Based on DTW:Taking the Backhand Topspin Loop for Example

运用高速动作捕捉技术,在采集国家队优秀乒乓球运动员(以下简称"国家队运动员")和青少年乒乓球运动员(以下简称"青少年运动员")基本技术动作的空间特征数据基础上,以反手拉上旋弧圈球为例,构建国家队运动员基本击球动作模型。运用动态时间规整(Dynamic Time Warping,DTW)算法,将青少年运动员的击球动作曲线与国家队运动员基本击球动作模型进行相似度比较,并结合击球质量数据对青少年运动员击球动作的合理性进行评价,分析其击球过程存在的问题。结果显示:①基于高速动作捕捉技术构建的国家队运动员击球动作模型能有效地对青少年运动员击球动作的合理性进行评价,具有一定的科学性。②将青少年运动员击球过程中各主要关节点运动轨迹和身体重心变换与国家队运动员的动作模型进行比较,可揭示青少年运动员击球过程中引拍、挥拍击球、还原三阶段各主要关节点运动轨迹和身体重心变换的合理性及不足,评价结果具有一定的可靠性。③通过对青少年运动员反手拉上旋弧圈球动作的合理性分析发现,该运动员引拍阶段右肩关节带动手臂向前移动的幅度较小,导致引拍不到位;还原阶段右肩关节还原幅度较小,重心稳定性较差。

High-speed motion capture technology was used to collect the spatial characteristic data of the basic technical movements from young table tennis players and national elite players. Taking the backhand topspin loop for instance,the DTW(Dynamic Time Warping)algorithm was used to construct the basic striking action model of the national team’s elite athletes,which can analyze the rationality and existing problems of the young players’ striking action. The evaluation model can be shown to effectively evaluate the rationality of the movements of the main joints and the transformation of the gravity center of young table tennis players in the process of striking the ball,including swinging the bat,strking the ball,and restoring to the original stance,compared with the striking action of the national elite players.The results find that the young player got a small range of the arm forward pulled by the movement of the right shoulder joint at the stage of swinging his bat,which led to the inadequate bat swing.A small range of the right shoulder joint caused the poor stability at the stage of the restoing to the original stance. This striking action model,constructed on the high-speed motion capture techinology of the national elite players,proves to be scientific.