Fig. 1From: Understanding patient preference in prosthetic ankle stiffnessVSPA Foot characterization. A VSPA Foot under load. The VSPA Foot has a mechanically-programmable torque–angle curve shape, determined by the shape of the cam. An onboard motor adjusts VSPA stiffness during the swing phase of gait. B VSPA dorsiflexion stiffness versus slider position. Light line shows a second-order polynomial fit to experimental characterization data (plotted points). Only dorsiflexion stiffness is shown; the device is three times more compliant in plantarflexionBack to article page