Kinetic Gait Analysis System Using Instrumented Insoles Based on Accessible Calibration with Wii Balance Board

Abstract

In previous works, instrumented insoles with a small number of force sensors have been proposed for kinetic gait analysis in small clinics, where costly force plates are not available. However, their calibration, which estimates vertical ground reaction force (vGRF) from their sensors, relied on the use of force plates. Therefore, this paper presents a novel calibration method of the insoles to estimate vGRF during walking using the Wii Balance Board (WBB) as an accessible alternative to force plates. The sensor forces were weighted using linear least-squares regression to fit to the measurements of the WBB during walking or standing. By comparison with force plates, the accuracies of the vGRF estimated by the proposed method using the measurements of walking through the WBB were equivalent to the force plate-based calibration. In addition, the method based on standing on the WBB did not have large deteriorations when compared to the walking-methods. From these results, the proposed calibration methods of the insoles using the WBB were valid for kinetic gait analysis.