Shiratori T, Latash M L
Department of Kinesiology, Rec. Hall-267, Pennsylvania State University, University Park, PA 16802, USA.
Clin Neurophysiol. 2001 Jul;112(7):1250-65. doi: 10.1016/s1388-2457(01)00553-3.
(1) To study differences in the generation of anticipatory postural adjustments (APAs) in arm and trunk/leg muscles prior to catching a load released either by the subject him-/herself or by the experimenter. (2) To study the importance of different mechanical characteristics of the load at impact for the generation of APAs prior to load catching.
Standing subjects were asked to catch loads dropped onto the left hand from different heights either by the experimenter or by the subject's right hand. The load mass and release height were manipulated to keep either the mass or the momentum of the load at impact constant. APAs were quantified with integral electromyographic indices.
APAs were observed in leg, trunk and arm muscles prior to load impact for both self- and experimenter-release trials. Kinetic energy showed higher correlations with the magnitude of APA than momentum, but only in experimenter-release trials.
Subjects can generate APAs in both arm and trunk/leg muscles in the absence of an explicit voluntary action. The relative importance of kinetic energy and momentum for defining the magnitude of APAs can reflect the difference in the sources of information used to prepare for the forthcoming perturbation during self- and experimenter-released load catch.
（1）研究在接住由受试者自身或实验者释放的负载之前，手臂和躯干/腿部肌肉中预期姿势调整（APA）的产生差异。（2）研究负载撞击时不同机械特性对负载接住前APA产生的重要性。
要求站立的受试者接住由实验者或受试者右手从不同高度落到其左手上的负载。通过操控负载质量和释放高度，使负载撞击时的质量或动量保持恒定。用积分肌电图指标对APA进行量化。
在自我释放和实验者释放试验中，在负载撞击前腿部、躯干和手臂肌肉中均观察到了APA。动能与APA大小的相关性高于动量，但仅在实验者释放试验中如此。
在没有明确自主动作的情况下，受试者能够在手臂和躯干/腿部肌肉中产生APA。动能和动量在定义APA大小方面的相对重要性可以反映在自我释放和实验者释放负载接住过程中用于为即将到来的扰动做准备的信息来源差异。
