Putnam C A
School of Physical Education, Dalhousie University, Halifax, Nova Scotia, Canada.
J Biomech. 1993;26 Suppl 1:125-35. doi: 10.1016/0021-9290(93)90084-r.
The motions of segments participating in striking and throwing skills are generally sequenced in a proximal-to-distal fashion. These sequences are often described in terms of the linear velocities of the segment endpoints, joint angular velocities or segment angular velocities. While each method of description has its own merit, the latter is recommended since it leads to an intuitively pleasing way of explaining segment motions. Explanations of segment motion sequences are dependent not only on a knowledge of the joint moments driving the system of linked segments, but on the way the segments interact as functions of their motions and orientations. The motion-dependent interaction among segments is significant and offers an explanation of the sequencing of segment motions. As illustrated by the thigh and lower leg in kicking and by the upper arm and forearm in overarm pitching, the forward acceleration of the proximal segment plays a large role in causing the distal segment to lag behind. The subsequent forward acceleration of the distal segment is largely a result of the way the proximal segment interacts with the distal segment as a function of the proximal segment's angular velocity. The proximal segment is subsequently slowed down largely due to the motion-dependent effect of the distal segment on the proximal segment. Differences in the way segments interact in striking and throwing skills can account for variations in the timing of segment actions and these differences need to be examined before establishing general principles governing striking and throwing.
参与击打和投掷技能的身体节段运动通常以近端到远端的方式进行排序。这些序列通常根据节段端点的线速度、关节角速度或节段角速度来描述。虽然每种描述方法都有其优点，但推荐使用后者，因为它能以一种直观且令人满意的方式解释节段运动。节段运动序列的解释不仅取决于驱动相连节段系统的关节力矩的知识，还取决于节段作为其运动和方向的函数相互作用的方式。节段之间与运动相关的相互作用很重要，并为节段运动的排序提供了解释。如踢腿时大腿和小腿以及上手投球时上臂和前臂所示，近端节段的向前加速在导致远端节段滞后方面起很大作用。远端节段随后的向前加速很大程度上是近端节段作为其角速度的函数与远端节段相互作用方式的结果。近端节段随后大幅减速主要是由于远端节段对近端节段的运动相关影响。节段在击打和投掷技能中相互作用方式的差异可以解释节段动作时间的变化，并且在确立关于击打和投掷的一般原则之前需要研究这些差异。
