Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
Hum Mov Sci. 2021 Apr;76:102765. doi: 10.1016/j.humov.2021.102765. Epub 2021 Jan 23.
To present and evaluate a method to objectively quantify the functional regions of joint lumped passive stiffness.
Joint passive stiffness has an important clinical role in constraining the degrees of freedom at a given joint. Links between passive stiffness and injury, pathology and function may be better understood if joint passive stiffness can be accurately quantified. Thus, a technique was developed to objectively partition passive stiffness curves into 3 linear regions (low, transition and high stiffness).
The passive stiffness of the lumbar spine is presented as an example. Simulated data was used to determine the sensitivity of the method to Gaussian white noise in force measurements. An experimentally determined lumbar passive flexion curve was used to demonstrate the technique on human data. Breakpoint analysis was employed on the resulting moment-angle cures to partition the curve into low, transition and high stiffness zones.
The proposed method was successful at discriminating between the three stiffness zones and quantifying the passive stiffness within each zone. The algorithm had difficulty determining parameters in the low-stiffness zone in the presence of noise.
The proposed method can be used as an objective method to investigate passive stiffness. Breakpoint Analysis can identify the three functional linear zones of passive stiffness. The slopes of these linear regions are then used as a measure of passive stiffness, which have applications in clinical populations and research studies, to assess time varying responses, or changes in stiffness following an intervention.
提出并评估一种客观量化关节集总被动刚度功能区的方法。
关节被动刚度在限制特定关节的自由度方面具有重要的临床作用。如果能够准确量化关节被动刚度，那么被动刚度与损伤、病理和功能之间的联系可能会得到更好的理解。因此，开发了一种技术将被动刚度曲线客观地划分为 3 个线性区域（低、过渡和高刚度）。
以腰椎为例介绍了被动刚度。使用模拟数据确定了该方法对力测量中高斯白噪声的敏感性。使用实验确定的腰椎被动弯曲曲线在人体数据上演示了该技术。在得到的力矩-角度曲线上进行断点分析，将曲线划分为低、过渡和高刚度区。
所提出的方法成功地区分了三个刚度区，并量化了每个区的被动刚度。在存在噪声的情况下，该算法难以确定低刚度区的参数。
所提出的方法可作为一种客观的方法来研究被动刚度。断点分析可以识别被动刚度的三个功能线性区。然后，这些线性区域的斜率可作为被动刚度的度量指标，可用于临床人群和研究中，以评估随时间变化的反应或干预后刚度的变化。
