Bouisset S, Zattara M
Laboratoire de Physiologie du Mouvement, UA CNRS, Université Paris-Sud, Orsay, France.
J Biomech. 1987;20(8):735-42. doi: 10.1016/0021-9290(87)90052-2.
The present research concerns anticipatory postural adjustments (APA), with the purpose of determining whether they are preprogrammed and of specifying their biomechanical finality. The experimental situation allowed us to distinguish between the voluntary movement itself (an upper limb elevation) and the postural adjustments associated with it. To this aim, the upper limb kinematics, evaluated from an accelerometer fixed at wrist level, were compared to the whole body dynamics, recorded by means of a force platform. Movements, executed in series of five, were studied according to three conditions: bilateral flexions (BF) and unilateral flexions (UF), with (IUF) and without (OUF) an additional inertia, of the stretched upper limb(s). Six right handed adults were tested twice. Results showed that the ground reaction resultant forces as well as the ground reaction resultant moment about the vertical axis presented reproducible variations before and after the onset of upper limb acceleration. The biomechanical organization of APA corresponded, for the three experimental conditions, to an upward and forward acceleration of the body center of gravity, and also, for UF, to a resultant moment directed towards the contralateral side. The duration of APA varied with the characteristics of the forthcoming voluntary movement, increasing significantly from BF to OUF and from OUF to IUF. It is concluded that APA correspond to dynamic phenomena which are centrally preprogrammed. The inertia forces associated with APA may, when the time comes, balance the inertia forces due to the movement of the mobile limb therefore counteracting the disturbance to postural equilibrium.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究关注预期姿势调整（APA），目的是确定其是否为预先编程以及明确其生物力学目的。实验情境使我们能够区分自愿运动本身（上肢抬高）及其相关的姿势调整。为此，将通过固定在手腕水平的加速度计评估的上肢运动学与通过力平台记录的全身动力学进行比较。以五个一组的方式进行的运动，根据三种条件进行研究：双侧屈曲（BF）和单侧屈曲（UF），伸展上肢的单侧屈曲有（IUF）和无（OUF）额外惯性。六名右利手成年人接受了两次测试。结果表明，在肢体加速开始之前和之后，地面反作用力以及绕垂直轴的地面反作用合力矩呈现出可重复的变化。对于这三种实验条件，APA的生物力学组织对应于身体重心向上和向前的加速度，对于UF，还对应于指向对侧的合力矩。APA的持续时间随即将进行的自愿运动的特征而变化，从BF到OUF以及从OUF到IUF显著增加。得出的结论是，APA对应于中枢预先编程的动态现象。当时机到来时，与APA相关的惯性力可能会平衡由于活动肢体运动产生的惯性力，从而抵消对姿势平衡的干扰。（摘要截断于250字）
