Figure 1.
Knee moment vs. angle curve for a representative subject walking at .
Letters a-f on the graph correspond to the poses shown during a typical walking cycle (top, schematic timing is adapted from [60]). Quasi-stiffness is calculated based on the slope of the best line fit to the moment-angle curve of a–b for the flexion stage (), and b–d for the extension stage (
) of the weight acceptance phase (a–d). The average of these two quasi-stiffness values is defined as the quasi-stiffness of the weight acceptance phase (
).
Table 1.
Details on Subjects and Experimental Trials used for Regression Fits.
Table 2.
General-Form Models to Predict the Quasi-Stiffness of the Knee Joint in Stance for Normal Walking.
Figure 2.
Knee quasi-stiffness for subject 10, as an example, in flexion (dark gray) and extension (light gray) stages, and weight acceptance phase (black) plotted against the gait speed.
The circles indicate the experimental values and the diamonds are the predictions of the general-form models (Table 2).
Figure 3.
The knee quasi-stiffness in the weight acceptance phase of the gait.
The experimental values are shown by circles, and the predictions of the general-form model by diamonds with average error of (14%), and the stature-based models by squares with average error of
(9%) for the optimal gait speed.
Table 3.
Stature-Based Models to Predict the Quasi-Stiffness of the Knee Joint in Stance for Normal Walking at Optimal Gait Speed.
Table 4.
Average Error Values for Different Models.