Persistent and anti-persistent pattern in stride-to-stride variability of treadmill walking: Influence of rhythmic auditory cueing

• Published in: Human movement science 2012-12, Vol.31 (6), p.1585-1597
• Main Authors: Terrier, Philippe, Dériaz, Olivier
• Format: Article
• Language: English
• Subjects: Acceleration; Acoustic Stimulation; Adult; Auditory Perception; Biological and medical sciences; Cues; DFA (Detrended Fluctuation Analysis); Exercise Test; Female; Fundamental and applied biological sciences. Psychology; Gait; Generalization (Psychology); Humans; Long-range correlations; Male; Middle Aged; Psychomotor performance; Statistics as Topic; Time Perception; Time series; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Walking - psychology
• ISSN: 0167-9457; 1872-7646
• DOI: 10.1016/j.humov.2012.05.004

► We studied statistical persistence of Stride Time (ST), Stride Length (SL) and Stride Speed (SS). ► When walking on a treadmill, ST and SL are persistent, while SS is anti-persistent. ► When rhythmic auditory cueing (metronome) is added, SL, ST and SS are anti-persistent. ► A model based on the redundancy theory in the movement control is proposed. ► The goal function constraining both ST and SS lead to a concomitant anti-persistence of SL, ST and SS. It has been observed that long time series of Stride Time (ST), Stride Length (SL) and Stride Speed (SS=SL/ST) exhibited statistical persistence (long-range auto-correlation) in overground walking. Rhythmic auditory cueing induced anti-persistent (or anti-correlated) patterns in ST series, while SL and SS remained persistent. On the other hand, it has been shown that SS became anti-persistent in treadmill walking, while ST and SL remained persistent. The aim of this study was to analyze the effect of the combination of treadmill walking (imposed speed) and auditory cueing (imposed cadence) on gait dynamics. Twenty middle-aged subjects performed 6×5min walking trials at various imposed speeds on an instrumented treadmill. Freely chosen walking cadences were measured during the first three trials, and then imposed accordingly in the last three trials by using a metronome. Detrended fluctuation analysis (DFA) was performed on the times series of ST, SL, and SS. Treadmill induced anti-persistent dynamics in the time series of SS, but preserved the persistence of ST and SL. On the contrary, all the three parameters were anti-persistent under dual-constraints condition. Anti-persistent dynamics may be related to a tighter control: deviations are followed by a rapid over-correction, which produces oscillations around target values. Under single constraint condition, while SS is tightly regulated in order to follow the treadmill speed, redundancy between ST and SL would likely allow persistent pattern to occur. Conversely, under dual constraint conditions, the absence of redundancy among SL, ST and SS would explain the generalized anti-persistent pattern.