Abstract：
This work illustrates the sensitivity of demographically characteristic body segment inertial properties and subject-specific customization on model performance. One characteristic demographic, gender, and one subject-specific characteristic, hip joint center location, were represented with musculoskeletal modeling to evaluate how design decisions may alter model outputs. Generic sexually dimorphic musculoskeletal models were developed from the commonly used Rajagopal model using male and female data adapted by Dumas et al. Hip joint centers of these models were adjusted based on functional joint center testing. The kinematics and dynamics of 40 gait cycles from four subjects are predicted using these models. Two-way analysis of variance (ANOVA) was performed on the continuous time series data using statistical parametric mapping (SPM) to assess changes in kinematics/dynamics due to either choice in model (Rajagopal vs Dumas) or whether joint center adjustment was performed. The SPM based two-way ANOVA of the inverse dynamics found that differences in the Rajagopal and Dumas models resulted in significant differences in sagittal plane moments during swing (0.115 ± 0.032 Nm/kg difference in mean hip flexion moment during initial swing and a 0.077 ± 0.041 Nm/kg difference in mean hip extension moment during terminal swing), and differences between the models with and without hip joint center adjustment resulted in significant differences in hip flexion and abduction moments during stance (0.217 ± 0.055 Nm/kg increased mean hip abductive moment). By comparing the outputs of these differently constructed models with each other, the study finds that dynamic predictions of stance are sensitive to positioning of joint centers, and dynamic predictions of swing are more sensitive to segment mass/inertial properties.
摘要：
这项工作说明了人口统计特征的身体部分惯性特性和特定主题定制对模型性能的敏感性。一个特征人口统计，性别,和一个特定主题的特征，髋关节中心位置,用肌肉骨骼建模表示，以评估设计决策如何改变模型输出。使用Dumas等人改编的男性和女性数据，从常用的Rajagopal模型开发了通用的性二态肌肉骨骼模型。这些模型的髋关节中心根据功能关节中心测试进行调整。使用这些模型预测了来自四个受试者的40个步态周期的运动学和动力学。使用统计参数映射（SPM）对连续时间序列数据进行双向方差分析（ANOVA），以评估由于模型选择（RajagopalvsDumas）或是否进行了关节中心调整而引起的运动学/动力学变化。基于SPM的反向动力学双向方差分析发现，Rajagopal和Dumas模型的差异导致挥杆期间矢状平面力矩的显着差异（初始挥杆期间平均髋部屈曲力矩差异为0.115±0.032Nm/kg，最终挥杆期间平均髋部伸展力矩差异为0.077±0.041Nm/kg），并且在有和没有髋关节中心调整的模型之间的差异导致站立期间髋关节屈曲和外展力矩的显着差异（0.217±0.055Nm/kg增加平均髋关节外展力矩）。通过将这些不同构造的模型的输出相互比较，研究发现，姿态的动态预测对关节中心的定位很敏感，和摆动的动态预测对分段质量/惯性特性更敏感。
