Journal of biomechanical engineering
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A custom program for the processing of pressure sensitive (Fuji) film data is presented and validated in this paper. Some of the shortcomings of previous descriptions of similar programs in literature are addressed. These shortcomings include incomplete descriptions of scan resolution, processing technique, and accuracy of results. ⋯ The accuracy of this program and that of the two commercially available image processing programs were determined. The results of the custom program are found to be within 10% of the results from the commercial programs and from experimental data. This level of accuracy is the same reported level of accuracy of Fuji film, verifying the custom program for use in Fuji film contact pressure and area measurements.
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Comparative Study
A simple mass-spring model with roller feet can induce the ground reactions observed in human walking.
It has previously been shown that a bipedal model consisting of a point mass supported by spring limbs can be tuned to simulate periodic human walking. In this study, we incorporated roller feet into the spring-mass model and evaluated the effect of roller radius, impact angle, and limb stiffness on spatiotemporal gait characteristics, ground reactions, and center-of-pressure excursions. We also evaluated the potential of the improved model to predict speed-dependent changes in ground reaction forces and center-of-pressure excursions observed during normal human walking. ⋯ Increases in either limb stiffness or impact angle tended to result in more oscillatory vertical ground reactions. Simultaneous modulation of the limb impact angle and limb stiffness was needed to induce speed-related changes in ground reactions that were consistent with those measured during normal human walking, with better quantitative agreement achieved at slower speeds. We conclude that a simple mass-spring model with roller feet can well describe ground reaction forces, and hence center of mass motion, observed during normal human walking.