Biomechanical capabilities influence postural control strategies in the cat hindlimb
Biomechanical capabilities influence postural control strategies in the cat hindlimb
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DOI：
10.1016/j.jbiomech.2006.10.013
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发表时间：
2007-01-01
影响因子：
2.4
通讯作者：
Ting, Lena H.
中科院分区：
文献类型：
--
作者：
McKay, J. Lucas;Burkholder, Thomas J.;Ting, Lena H.
在对扰动的姿势反应期间，由猫后肢产生的水平面力被刻板地指向朝向或远离动物的质心，而与扰动方向无关。我们使用了一个静态的，三维的后肢肌肉骨骼模型来研究这种“力约束策略”的可能的生物力学决定因素。“我们假设后肢可以产生大力量的方向优先用于姿势控制。我们计算可行的力集（FFSs）的基础上，后肢配置的三只猫在姿势平衡任务，并将它们与水平面姿势力的方向。总平均FFS为双峰，最大值位于后-前轴附近（-86 +/- 8度和71 +/- 4度），最小值位于内外轴附近（177 +/- 8度和8 +/- 8度）。实验姿势力方向聚集在两个最大值附近;绝对最小值附近没有内侧姿势力。然而，右后肢中的前后姿势力方向直方图的中值从FFS最大值逆时针旋转（p < 0.05; Wilcoxon符号秩检验）。由于FFS的后-前对齐与针对运动优化的后肢结构一致，我们得出结论，后肢的生物力学能力强烈影响力约束策略中观察到的力方向，但不能唯一确定力约束策略中观察到的力方向。姿势控制中使用的力可能反映了在大的可行力的方向上使用力的神经偏好与其他标准（例如质心的稳定性和肌肉协调策略）之间的平衡。(C)2006爱思唯尔有限公司保留所有权利。
During postural responses to perturbations, horizontal plane forces generated by the cat hindlimb are stereotypically directed either towards or away from the animal's center of mass, independent of perturbation direction. We used a static, three-dimensional musculoskeletal model of the hindlimb to investigate possible biomechanical determinants of this "force constraint strategy." We hypothesized that directions in which the hindlimb can produce large forces are preferentially used in postural control. We computed feasible force sets (FFSs) based on hindlimb configurations of three cats during postural equilibrium tasks and compared them to horizontal plane postural force directions. The grand mean FFS was bimodal, with maxima near the posterior-anterior axis (-86 +/- 8 degrees and 71 +/- 4 degrees), and minima near the medial-lateral axis (177 +/- 8 degrees and 8 +/- 8 degrees). Experimental postural force directions clustered near both maxima; there were no medial postural forces near the absolute minimum. However, the medians of the anterior and posterior postural force direction histograms in the right hindlimb were rotated counter-clockwise from the FFS maxima (p < 0.05; Wilcoxon signed-rank test). Because the posterior-anterior alignment of the FFS is consistent with a hindlimb structure optimized for locomotion, we conclude that the biornechanical capabilities of the hindlimb strongly influence, but do not uniquely determine the force directions observed in the force constraint strategy. Forces used in postural control may reflect a balance between a neural preference for using forces in the directions of large feasible forces and other criteria, such as the stabilization of the center of mass, and muscular coordination strategies. (C) 2006 Elsevier Ltd. All rights reserved.