Repeatability of an off-the-shelf, full body inertial motion capture system during clinical gait analysis

Background and aims: To establish gait analysis as part of routine clinical diagnoses, physicians demand accurate and flexible motion capture (Mocap). Currently, popular optical, mechanical and acoustic Mocap systems offer acceptable repeatability, but fall short of the spatial and economic benefits accompanying inertial motion capture (IMC). However, IMC is considered adolescent due to limited testing in gait analysis. This paper aims to address this hindrance through within-day and between test day repeatability studies. Methods: To determine the repeatability of IMC, routine gait studies were done on 30 able-bodied males. Repeatability was quantified using the coefficient of multiple determination (CMD) and the coefficient of multiple correlation (CMC). Results: IMC-recorded kinematics were highly repeatable for within-day (CMD: 0.786-0.984 or CMC: 0.881-0.992) and between-day trials (CMD: 0.771-0.991 or CMC: 0.872-0.995). The results compare well to those from similar repeatability studies in the literature based on optical Mocap systems.