Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire, L39 4QP, UK.
Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire, L39 4QP, UK.
Gait Posture. 2021 Sep;89:1-6. doi: 10.1016/j.gaitpost.2021.06.016. Epub 2021 Jun 22.
The conventional gait model (CGM) is commonly utilised within clinical motion analysis but has a number of inherent limitations. To overcome some of these limitations modifications have been made to the CGM and six-degrees of freedom models (6DoF) have been developed.
How comparable are lower limb kinematics calculated using modified CGM and 6DoF models and what is the error associated with the output of each model during walking?
Ten healthy males attended two gait analysis sessions, in which they walked at a self-selected pace, while a 10-camera motion capture system recorded lower limb kinematics. Hip, knee and ankle joint kinematics in all three anatomical planes were calculated using a modified CGM, with medial anatomical markers and a three-dimensional foot added, and 6DoF. Mean absolute differences were calculated on a point-by-point basis over the walking gait cycle and interpreted relative to a 5° threshold to explore the comparability of model outputs. The standard error of the measurement (SEM) was also calculated on a point-by-point basis over the walking gait cycle for each model.
Mean absolute differences above 5° were reported between the two model outputs in 58-86% of the walking gait cycle at the knee in the frontal plane, and over the entire walking gait cycle at the hip and knee in the transverse plane. SEM was typically larger for the modified CGM compared to the 6DoF, with the highest SEM values reported at the knee in the frontal plane, and the hip and the knee in the transverse plane.
Caution should be taken when looking to compare findings between studies utilising modified CGM and 6DoF outside of the sagittal plane, especially at the hip and knee. The reduced SEM associated with the 6DoF suggests this modelling approach may be preferable.
传统步态模型（CGM）在临床运动分析中被广泛应用，但存在许多固有局限性。为了克服这些局限性，对 CGM 进行了修改，并开发了六自由度模型（6DoF）。
使用修改后的 CGM 和 6DoF 模型计算下肢运动学的结果有何可比性，以及在行走过程中每个模型输出的误差是多少？
10 名健康男性参加了两次步态分析测试，在测试中他们以自主选择的速度行走，同时使用 10 个摄像机运动捕捉系统记录下肢运动学。使用修改后的 CGM 计算了所有三个解剖平面的髋关节、膝关节和踝关节运动学，该模型添加了内侧解剖标记和三维足，并使用 6DoF。在行走步态周期的逐点基础上计算了平均绝对差异，并相对于 5°的阈值进行解释，以探索模型输出的可比性。还在行走步态周期的逐点基础上计算了每个模型的测量标准误差（SEM）。
在额状面的膝关节、横状面的髋关节和膝关节的整个行走步态周期中，两种模型输出之间报告的平均绝对差异超过 5°的比例为 58-86%。与 6DoF 相比，修改后的 CGM 的 SEM 通常更大，在额状面的膝关节、横状面的髋关节和膝关节处报告了最高的 SEM 值。
在矢状面以外的研究中，当试图比较使用修改后的 CGM 和 6DoF 的研究结果时，应谨慎行事，尤其是在髋关节和膝关节处。与 6DoF 相关的 SEM 降低表明，这种建模方法可能更可取。
