Effects of unexpected speed changes on similarity of gait kinematics

Abrupt changes in speed due to external disturbances can occur during human gait. Insight into the gait compensation mechanism is necessary to examine gait stability in the context of unexpected speed changes. The present study investigated the effect of speed changes on overall gait patterns under three different walking speed conditions. Dynamic time warping (DTW) and cross-correlation techniques were used, revealing that similarity of gait kinematics decreased at slower gait speed compared to preferred and faster speeds. These results suggest that individuals may encounter difficulties in maintaining gait stability at slower speed than normal and faster speeds. Additionally, at the moment when speed changes occur, the similarity of gait patterns significantly decreases, as indicated by higher DTW and cross-correlation values. This insight could assist clinicians and physical therapists in gaining an understanding of overall gait patterns during unexpected speed changes and developing assistive devices to prevent slips, trips, and falls.