An evaluation of optimization techniques for the prediction of muscle activation patterns during isometric tasks
An evaluation of optimization techniques for the prediction of muscle activation patterns during isometric tasks
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DOI：
10.1115/1.2796044
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发表时间：
1996-11-01
影响因子：
1.7
通讯作者：
Shreeve, DA
中科院分区：
文献类型：
--
作者：
Buchanan, TS;Shreeve, DA
本研究的目的是严格评估建模潜力的建议优化成本函数预测肌肉力量在等长负荷。建立了手肘（11块肌肉）和腕关节（5块肌肉）的肌肉模型。这些模型考虑了肌肉力矩臂、生理横截面积、比张力和纤维类型百分比。五个非线性优化成本函数。分析了迄今为止提出的那些的代表性样本：最小化肌肉力（2）、应力（2）、应力（3）、（归一化力）（2）的总和，以及最小化疲劳。实施了几种不同的方案，包括平衡屈曲-伸展、旋后-旋前和内翻-外翻载荷组合的肘关节模型。理论预测进行了比较与肌电数据的肌肉激活变化的功能elf负荷方向和肌肉共激活的关系。结果表明，肌肉协调预测的自由度平衡的数量的依赖性很强。成本函数的选择对结果的影响很小。检查的成本函数也不能可靠地估计肌肉激活作为负载方向的函数。此外，肌肉对之间的特定协同关系不能准确地表示。误差分析表明，预测值和实际值之间的差异不能用生理测量误差来解释，因为这两者之间的差异对解剖参数的变化相对不敏感。简而言之，没有发现特定的成本函数足以代表手肘的实际肌肉活动，尽管由于关节自由度的差异，手腕处的预测更有利。
The purpose of this study was to critically evaluate the modeling potential of proposed optimization cost functions for predicting muscle forces during isometric loading. Models of the muscles about the elbow (eleven muscles) and wrist (five muscles) were constructed. The models accounted for muscle moment arms, physiological cross-sectional area, specific tension, and percent fiber type. Five nonlinear optimization cost functions. a representative sample of those proposed to date, were analyzed: minimizing the sums of muscle force(2), stress(2), stress(3), (normalized force)(2), and minimizing fatigue. Several different protocols were implemented, including elbow models which balanced combinations of flexion-extension, supination-pronation, and varus-valgus loads. Theoretical predictions were compared with EMG data of muscle activation changes as a function elf load direction and muscle coactivation relationships. Results indicate a strong dependence of muscle coordination predictions on the number of degrees of freedom balanced The choice of cost function had little influence on the results. The cost functions examined were nor able to reliably estimate muscle activation as a function of load direction. Furthermore, specific synergic relationships between muscle pairs could not be accurately represented. An error analysis indicated that the discrepancies between predicted values and actual values could not be explained by errors in physiological measurements, as the differences between these two were relatively insensitive to changes in the anatomical parameters. In short, no particular cost function was found to adequately represent actual muscle activity at the elbow, although predictions at the wrist were more favorable due to differences in the degrees of freedom at the joints.