Bradshaw Mark F, Watt Simon J, Elliott Kathleen M, Riddell Patricia M
Department of Psychology, School of Human Sciences, University of Surrey, Guildford GU2 5XH, UK.
Hum Mov Sci. 2004 Dec;23(6):771-84. doi: 10.1016/j.humov.2004.07.003.
The present study examined the effects of a pre-movement delay on the kinematics of prehension in middle childhood. Twenty-five children between the ages of 5 and 11 years made visually open-loop reaches to two different sized objects at two different distances along the midline. Reaches took place either (i) immediately, or (ii) 2 s after the occlusion of the stimulus. In all age groups, reaches following the pre-movement delay were characterised by longer movement durations, lower peak velocities, larger peak grip apertures and longer time spent in the final slow phase of the movement. This pattern of results suggests that the representations that control the transport and grasp component are affected similarly by delay, and is consistent with the results previously reported for adults. Such representations therefore appear to develop before the age of 5.
本研究考察了运动前延迟对童年中期抓握运动学的影响。25名5至11岁的儿童沿中线在两个不同距离对两个不同大小的物体进行视觉开环伸手动作。伸手动作要么（i）在刺激消失后立即进行，要么（ii）在刺激消失2秒后进行。在所有年龄组中，运动前延迟后的伸手动作的特点是运动持续时间更长、峰值速度更低、峰值抓握孔径更大以及在运动的最后缓慢阶段花费的时间更长。这种结果模式表明，控制运输和抓握部分的表征受到延迟的影响类似，这与之前针对成年人报告的结果一致。因此，这种表征似乎在5岁之前就已形成。
