Nicholas S C, Doxey-Gasway D D, Paloski W H
Neurosciences Laboratory, Krug Life Sciences, Houston, Texas, USA.
J Vestib Res. 1998 May-Jun;8(3):187-200.
Sensory-motor control of upright human posture may be organized in a top-down fashion such that certain head-trunk coordination strategies are employed to optimize visual and/or vestibular sensory inputs. Previous quantitative models of the biomechanics of human posture control have examined the simple case of ankle sway strategy, in which an inverted pendulum model is used, and the somewhat more complicated case of hip sway strategy, in which multisegment, articulated models are used. While these models can be used to quantify the gross dynamics of posture control, they are not sufficiently detailed to analyze head-trunk coordination strategies that may be crucial to understanding its underlying mechanisms. In this paper, we present a biomechanical model of upright human posture that extends an existing four mass, sagittal plane, link-segment model to a five mass model including an independent head link. The new model was developed to analyze segmental body movements during dynamic posturography experiments in order to study head-trunk coordination strategies and their influence on sensory inputs to balance control. It was designed specifically to analyze data collected on the EquiTest (NeuroCom International, Clackamas, OR) computerized dynamic posturography system, where the task of maintaining postural equilibrium may be challenged under conditions in which the visual surround, support surface, or both are in motion. The performance of the model was tested by comparing its estimated ground reaction forces to those measured directly by support surface force transducers. We conclude that this model will be a valuable analytical tool in the search for mechanisms of balance control.
直立人体姿势的感觉运动控制可能是以自上而下的方式组织的，即采用某些头部 - 躯干协调策略来优化视觉和/或前庭感觉输入。以前关于人体姿势控制生物力学的定量模型研究了简单的脚踝摆动策略情况（使用倒立摆模型）以及稍微复杂一些的髋部摆动策略情况（使用多节段、关节模型）。虽然这些模型可用于量化姿势控制的总体动态，但它们不够详细，无法分析对于理解其潜在机制可能至关重要的头部 - 躯干协调策略。在本文中，我们提出了一个直立人体姿势的生物力学模型，该模型将现有的四质量、矢状面、连杆 - 节段模型扩展为包括独立头部连杆的五质量模型。开发新模型是为了分析动态姿势描记实验期间的身体节段运动，以便研究头部 - 躯干协调策略及其对平衡控制感觉输入的影响。它专门设计用于分析在EquiTest（NeuroCom International，Clackamas，俄勒冈州）计算机化动态姿势描记系统上收集的数据，在该系统中，当视觉环境、支撑表面或两者都处于运动状态时，维持姿势平衡的任务可能会受到挑战。通过将其估计的地面反作用力与支撑表面力传感器直接测量的力进行比较来测试模型的性能。我们得出结论，该模型将成为寻找平衡控制机制的有价值的分析工具。
