Laurent M, Montagne G, Savelsbergh G J
Faculty of Human Movement Sciences, Free University, Amsterdam, The Netherlands.
Exp Brain Res. 1994;101(2):314-22. doi: 10.1007/BF00228752.
The aim of the experiment was to identify the control mechanisms involved in a goal-directed task by manipulating the temporal constraints. Subjects were required to catch, with one hand, table tennis balls projected by a ball-projection machine under five temporal conditions (ball speed ranged from 5.7 to 9 m/s, giving rise to flight times of 550-350 ms). By means of three-dimensional kinematics analysis the following results were obtained, which are some spatio-temporal adaptations of the catching movement to the increase of temporal constraints: (1) a decrease in movement time, (2) an increase in the straightness of the trajectory of the wrist, and (3) a shift backwards of the place of ball-hand contact while (4) the grasping time was kept constant. Moreover, as a result of increasing temporal constraints, the acceleration phase of the transportation component was kept constant while the deceleration phase was progressively decreased and nearly suppressed. Further, an increased correlation of the initial direction of the transportation component with the initial direction of the ball path was found. These findings show some spatio-temporal adaptations of the catching movement when the time available is manipulated. They also support the contention of a shift in the control mechanisms involved in one-handed catching facing different temporal constraints.
该实验的目的是通过操纵时间限制来确定目标导向任务中涉及的控制机制。要求受试者用一只手接住由投球机在五种时间条件下投射出的乒乓球（球速范围为5.7至9米/秒，飞行时间为550 - 350毫秒）。通过三维运动学分析得到了以下结果，这些结果是接球动作对时间限制增加的一些时空适应性表现：（1）运动时间减少；（2）手腕轨迹的直线度增加；（3）球与手接触位置向后移动，同时（4）抓握时间保持不变。此外，由于时间限制增加，运输部分的加速阶段保持不变，而减速阶段逐渐减少并几乎被抑制。此外，还发现运输部分的初始方向与球路径的初始方向之间的相关性增加。这些发现表明，当可用时间被操纵时，接球动作存在一些时空适应性。它们也支持了这样一种观点，即面对不同的时间限制时，单手接球所涉及的控制机制会发生转变。
