Gait Percent Estimation during Walking and Running using Sagittal Shank or Thigh Angles

In this work we analyzed the relationship between the shank and thigh angles (separately) and the gait cycle progression, to develop a novel approach for gait percent estimation. To do so, the angles were integrated. Our findings show that the integral of shank and thigh angle has a monotonic behavior and therefore can approximate the gait percents during a gait cycle through a one-to-one relationship. For all of the individuals, speeds and gaits a quasi-linear relationship was found between the shank and thigh angle integrals and the gait percents. Average $\mathrm{R}^{2}$ values close to one and average RMS errors less than 2.2 were achieved. The proposed approach was investigated for different subjects (21 subjects), speeds (10 speeds) and gaits (walking and running) and can be potentially used for human motion analysis as well as for motion planning of assistive devices.