Reversals of anticipatory postural adjustments during voluntary sway in humans
Reversals of anticipatory postural adjustments during voluntary sway in humans
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DOI：
10.1113/jphysiol.2005.084772
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发表时间：
2005-06-01
影响因子：
5.5
通讯作者：
Latash, ML
中科院分区：
文献类型：
--
作者：
Krishnamoorthy, V;Latash, ML
我们描述了预期姿势调整(APA)与自愿循环全身摇摆运动阶段的逆转。受试者(n=9)在摇摆的不同阶段伸展双臂握住标准负荷，并以自定步调的双肩外展动作释放标准负荷。释放载荷的任务也是在安静的站姿下进行的，有三个位置：摇摆范围的中间和接近其极端的向前和向后位置。与安静的姿势相比，在摇摆任务中可以看到更大的APA。虽然与负荷释放相关的姿势扰动方向总是相同的，但与其他阶段和安静站立时相比，当受试者接近最前方姿势时，腿部肌肉中APA的方向相反。躯干肌肉在末端位置的APA调制较小，但在穿过中间位置时的调制较大，这取决于摇摆的方向，向前或向后。动静脉动反转现象强调了安全在产生与自愿行动相关的姿势调整方面的重要作用。基于这些发现，APA可以被定义为与可预测的扰动相关的姿势肌肉活动的变化，其作用是为姿势任务部分提供最大的安全性。
We describe reversals of anticipatory postural adjustments (APAs) with the phase of a voluntary cyclic whole-body sway movement. Subjects (n = 9) held a standard load in extended arms and released it by a bilateral shoulder abduction motion in a self-paced manner at different phases of the sway. The load release task was also performed during quiet stance in three positions: in the middle of the sway range and close to its extreme forward and backward positions. Larger APAs were seen during the sway task as compared to quiet stance. Although the direction of postural perturbation associated with the load release was always the same, the direction of the APAs in the leg muscles reversed when the subjects were close to the extreme forward position as compared to the APAs in other phases and during quiet stance. The trunk muscles showed smaller APA modulation at the extreme positions but larger modulation when passing through the middle position, depending on the direction of sway, forward or backward. The phenomenon of APA reversals emphasizes the important role of safety in the generation of postural adjustments associated with voluntary movements. Based on these findings, APAs could be defined as changes in the activity of postural muscles associated with a predictable perturbation that act to provide maximal safety of the postural task component.