Intra-subject stride-to-stride variability: Selecting subject's representative gait pattern

Stride-to-stride variability is well known and important phenomenon often used for estimation of the gait fluctuations and indicative measure for potential risk of falling in elderly. In many gait analysis studies and the descriptions of new processing and analysis methods, the problem of selecting representative gait cycle is solved with choosing one gait cycle from the middle of the recording sequence, or averaging several cycles from the middle. In this paper, we describe stride-to-stride variability based on data from inertial sensors. We suggest a simple, mathematical method, how to select stride which best represents the subject's gait pattern.