Kinetic chain of overarm throwing in terms of joint rotations revealed by induced acceleration analysis
Kinetic chain of overarm throwing in terms of joint rotations revealed by induced acceleration analysis
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DOI：
10.1016/j.jbiomech.2008.06.014
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发表时间：
2008-09-18
影响因子：
2.4
通讯作者：
Ohtsuki, Tatsuyuki
中科院分区：
文献类型：
--
作者：
Hirashima, Masaya;Yamane, Katsu;Ohtsuki, Tatsuyuki
本研究旨在探讨棒球选手如何借由协调过肩投掷时的关节力矩与速度相关力矩，在各关节产生较大的角速度。使用四段模型（即，躯干、上臂、前臂和手），我们进行了感应加速度分析，通过将系统惯性矩阵的倒数乘以扭矩矢量来确定由这些扭矩引起的加速度。我们发现近端关节运动（即，躯干向前运动、躯干后旋和肩部内旋）主要由其自身关节处的关节扭矩加速，而远端关节运动（即，肘关节伸展和腕关节屈曲）主要由速度依赖性扭矩加速。我们进一步研究了哪一段运动是作用在手肘和手腕加速度上的速度相关扭矩的来源。结果表明，躯干和上臂的角速度产生的速度依赖性扭矩的初始伸肘加速度。结果，手肘关节角速度增加，同时，前臂相对于地面的角速度也增加。前臂角速度随后加速手肘伸展和腕关节屈曲。它也加速了肩关节的内旋，在短时间内球释放时间。这些结果表明，棒球运动员通过利用最初由近端躯干和肩关节扭矩在早期阶段产生的速度依赖性扭矩来加速远端肘关节和腕关节旋转。(C)2008爱思唯尔有限公司版权所有。
This Study investigated how baseball players generate large angular velocity at each joint by coordinating the joint torque and velocity-dependent torque during overarm throwing. Using a four-segment model (i.e., trunk, upper arm, forearm, and hand) that has 13 degrees of freedom, we conducted the induced acceleration analysis to determine the accelerations induced by these torques by multiplying the inverse of the system inertia matrix to the torque vectors. We found that the proximal joint motions (i.e., trunk forward motion, trunk leftward rotation, and shoulder internal rotation) were mainly accelerated by the joint torques at their own joints, whereas the distal joint motions (i.e., elbow extension and wrist flexion) were mainly accelerated by the velocity-dependent torques. We further examined which segment motion is the source of the velocity-dependent torque acting on the elbow and wrist accelerations. The results showed that the angular velocities of the trunk and upper arm produced the velocity-dependent torque for initial elbow extension acceleration. As a result, the elbow joint angular velocity increased, and concurrently, the forearm angular velocity relative to the ground also increased. The forearm angular velocity subsequently accelerated the elbow extension and wrist flexion. It also accelerated the shoulder internal rotation during, the short period around the ball-release time. These results indicate that baseball players accelerate the distal elbow and wrist joint rotations by utilizing the velocity-dependent torque that is originally produced by the proximal trunk and shoulder joint torques in the early phase. (C) 2008 Elsevier Ltd. All rights reserved.