Long-Range Correlations of Stride Time, Stride Length and Stride Velocity during Feedback-Controlled Treadmill Walking

The gait fractal dynamics during between conventional treadmill (CTM) and feedback-controlled treadmill (FTM) walking were compared in this study. Seven healthy male subjects performed for 5 min walking with each treadmill condition. FTM can be tuned its belt speed to walker’s speed, which controls belt speed by walker’s anterior-posterior location by using installed-loadcell under treadmill floor. Each subject’s preferred walking speed was determined by FTM walking, and those were used for a belt speed of CTM. 3D motion analysis system was used for acquiring motion data of the toe and heel markers. To compare gait fractal dynamics in both treadmill conditions, α of detrended fluctuation analysis (DFA) was calculated. In general, α represents that it has persistence of long-range correlation or not (α > 0.5: persistence, α ≤0.5, no persistence). The result showed that there was no significant difference in α of stride time between CTM and FTM while there were significant differences in α of stride length and stride velocity between both conditions. Especially, the long-range correlation of stride velocity was not persisted when they walked on the CTM while there is persistence in the FTM. It reveal that FTM walking, compared with CTM walking, was more similar to overground walking from fractal dynamics perspective. It is possible to apply for various walking studies by using FTM.