Abstract

The aim of this study was to develop a generic musculoskeletal model of a healthy 10-year-old child and examine the effects of geometric scaling on the calculated values of lower-limb muscle forces during gait. Subject-specific musculoskeletal models of five healthy children were developed from in vivo MRI data, and these models were subsequently used to create a generic juvenile (GJ) model. Calculations of lower-limb muscle forces for normal walking obtained from two scaled-generic versions of the juvenile model (SGJ1 and SGJ2) were evaluated against corresponding results derived from an MRI-based model of one subject (SSJ1). The SGJ1 and SGJ2 models were created by scaling the GJ model using gait marker positions and joint centre locations derived from MRI imaging, respectively. Differences in the calculated values of peak isometric muscle forces and muscle moment arms between the scaled-generic models and MRI-based model were relatively small. Peak isometric muscle forces calculated for SGJ1 and SGJ2 were respectively 2.2% and 3.5% lower than those obtained for SSJ1. Model-predicted muscle forces for SGJ2 agreed more closely with calculations obtained from SSJ1 than corresponding results derived from SGJ1. These results suggest that accurate estimates of muscle forces during gait may be obtained by scaling generic juvenile models based on joint centre locations. The generic juvenile model developed in this study may be used as a template for creating subject-specific musculoskeletal models of normally-developing children in studies aimed at describing lower-limb muscle function during gait.

摘要

本研究的目的是开发一个健康 10 岁儿童的通用肌肉骨骼模型，并检查几何缩放对步态过程中下肢肌肉力量计算值的影响。五个健康儿童的特定主题肌肉骨骼模型是根据体内 MRI 数据开发的，这些模型随后用于创建通用青少年 (GJ) 模型。对从少年模型的两个缩放通用版本（SGJ1 和 SGJ2）获得的正常行走的下肢肌肉力量的计算，根据来自一个受试者 (SSJ1) 的基于 MRI 的模型的相应结果进行评估。SGJ1 和 SGJ2 模型是通过分别使用从 MRI 成像得出的步态标记位置和关节中心位置对 GJ 模型进行缩放来创建的。缩放的通用模型和基于 MRI 的模型之间峰值等长肌肉力和肌肉力矩臂的计算值的差异相对较小。为 SGJ1 和 SGJ2 计算的峰值等长肌肉力分别比为 SSJ1 获得的低 2.2% 和 3.5%。SGJ2 的模型预测肌肉力与从 SSJ1 获得的计算结果比从 SGJ1 获得的相应结果更接近。这些结果表明，可以通过缩放基于关节中心位置的通用青少年模型来准确估计步态期间的肌肉力量。本研究中开发的通用青少年模型可用作模板，用于在旨在描述步态过程中下肢肌肉功能的研究中创建正常发育儿童的特定主题肌肉骨骼模型。