Implications of using hierarchical and six degree-of-freedom models for normal gait analyses
Implications of using hierarchical and six degree-of-freedom models for normal gait analyses
复制标题
DOI：
10.1016/j.gaitpost.2009.08.245
复制
发表时间：
2010-01-01
期刊：
影响因子：
2.4
通讯作者：
Sanders, James O.
中科院分区：
文献类型：
--
作者：
Buczek, Frank L.;Rainbow, Michael J.;Sanders, James O.
分层生物力学模型（传统步态模型，CGM）是有吸引力的，因为简单的数据收集要求，但他们容易受到错误，理论上更好地控制使用六个自由度的模型，独立跟踪身体部分（OPT 1）。我们希望比较这些模型获得的步态变量。25名正常儿童在佩戴混合标记配置时行走，允许使用CGM和OPT 1分析相同的步幅。使用一个共同的运动捕捉系统获得的kinetics和地面反作用力。CGM和OPT 1在Visual 3D软件中实现，其中逆动力学提供了20个临床相关步态变量（关节角度、力矩和功率）。使用依赖性t检验（Bonferroni调整α为0.0025）和总体平均值在模型之间进行比较。我们假设OPT 1在矢状面提供的数据与CGM相似，在冠状面和横断面提供的数据与CGM不同。矢状面中有6个变量存在显著差异，表明CGM产生了更长的下肢;这可以通过膝关节屈曲期间外侧膝关节标记的后偏（皮肤运动伪影所致）来解释。冠状面变量无显著差异。四个变量在横向平面上有显著差异。两种型号之间的平均值具有可比性。对于正常儿童，基于这些测试变量的生物力学解释不太可能因单独的节段跟踪而发生变化（CGM与OPT 1）。由于病理学原因，以及当节段参考帧从CGM中使用的参考帧改变以反映个体解剖结构时，可能会出现其他差异。(C)2009年爱思唯尔B。V.保留所有权利。
Hierarchical biomechanical models (conventional gait model, CGM) are attractive because of simple data collection demands, yet they are susceptible to errors that are theoretically better controlled using six degree-of-freedom models that track body segments independently (OPT1). We wished to compare gait variables obtained with these models. Twenty-five normal children walked while wearing a hybrid marker configuration, permitting identical strides to be analyzed using CGM and OPT1. Kinematics and ground reaction forces were obtained using a common motion capture system. CGM and OPT1 were implemented in Visual3D software, where inverse dynamics provided 20 clinically relevant gait variables (joint angles, moments and powers). These were compared between models using dependent t-tests (Bonferroni-adjusted alpha of 0.0025), and ensemble averages. We hypothesized that OPT1 would provide data similar to CGM in the sagittal plane, and different from CGM in coronal and transverse planes. Six variables were significantly different in the sagittal plane, suggesting that CGM produced a more extended lower extremity; this was explained by a posterior bias to the lateral knee marker during knee flexion, as a result of skin movement artifact. No significant differences were found in coronal plane variables. Four variables were significantly different in the transverse plane. Ensemble averages were comparable between models. For normal children, biomechanical interpretations based upon these tested variables are unlikely to change due to independent segment tracking alone (CGM vs. OPT1). Additional differences may appear due to pathology, and when segment reference frames are changed from those used in CGM to reflect individual anatomy. (C) 2009 Elsevier B. V. All rights reserved.