Development and Assessment of a Low-Cost Clinical Gait Analysis System.

Clinically, measuring gait kinematics and ground reaction force (GRF) is useful to determine the effectiveness of treatment. However, it is inconvenient and expensive to maintain a laboratory-grade gait analysis system in most clinics. The purpose of this study was to validate a Wii Balance Board, Kinovea motion-tracking software, and a video camera as a portable, low-cost, overground gait analysis system. We validated this low-cost system against a multi-camera Vicon system and AMTI force platform. After validation trials with known weights and angles, five subjects walked across an instrumented walkway multiple times (n=8/subject). We collected vertical GRF and segment angles. Average GRF data from the two systems were similar, with peak GRF errors below 3.5%BW. However, variability in the balance board's sampling rate led to large GRF errors early and late in stance, when the GRF changed rapidly. The thigh, shank and foot angle measurements were similar between the single and multi-camera, but the pelvis angle was far less accurate. The proposed system has the potential to provide accurate segment angles and peak GRF at low cost, but does not match the accuracy of the multi-camera system and force platform, in part because of the Wii Balance Board's variable sampling rate.