Shriners Hospitals for Children, Erie, PA 16509, USA.
Gait Posture. 2012 Apr;35(4):535-40. doi: 10.1016/j.gaitpost.2011.11.012. Epub 2011 Dec 23.
Kinematic multi-segment foot models have seen increased use in clinical and research settings, but the addition of kinetics has been limited and hampered by measurement limitations and modeling assumptions. In this second of two companion papers, we complete the presentation and analysis of a three segment kinetic foot model by incorporating kinetic parameters and calculating joint moments and powers. The model was tested on 17 pediatric subjects (ages 7-18 years) during normal gait. Ground reaction forces were measured using two adjacent force platforms, requiring targeted walking and the creation of two sub-models to analyze ankle, midtarsal, and 1st metatarsophalangeal joints. Targeted walking resulted in only minimal kinematic and kinetic differences compared with walking at self selected speeds. Joint moments and powers were calculated and ensemble averages are presented as a normative database for comparison purposes. Ankle joint powers are shown to be overestimated when using a traditional single-segment foot model, as substantial angular velocities are attributed to the mid-tarsal joint. Power transfer is apparent between the 1st metatarsophalangeal and mid-tarsal joints in terminal stance/pre-swing. While the measurement approach presented here is limited to clinical populations with only minimal impairments, some elements of the model can also be incorporated into routine clinical gait analysis.
运动多节段足模型在临床和研究环境中得到了越来越多的应用，但动力学的加入受到测量限制和建模假设的限制，应用有限。在这两篇配套论文中的第二篇中，我们通过纳入动力学参数并计算关节力矩和功率，完成了三关节动力学足模型的介绍和分析。该模型在 17 名儿科受试者（7-18 岁）进行正常步态时进行了测试。使用两个相邻的力台测量地面反作用力，需要有针对性的行走，并创建两个子模型来分析踝关节、中跗关节和第 1 跖趾关节。与自行选择速度行走相比，有针对性的行走仅导致最小的运动学和动力学差异。计算了关节力矩和功率，并作为比较目的的规范数据库呈现了总体平均值。当使用传统的单节段足模型时，踝关节的功率被高估，因为中跗关节的角速度很大。在终末站立/预摆动期间，第 1 跖趾关节和中跗关节之间存在明显的功率传递。虽然这里提出的测量方法仅限于只有最小损伤的临床人群，但该模型的某些元素也可以纳入常规临床步态分析。
