Kinematic Variability, Fractal Dynamics and Local Dynamic Stability of Treadmill Walking
By Terrier, Philippe; Deriaz, Olivier; Journal of NeuroEngineering and Rehabilitation, Vol. 8, No. 12Publication Date: February 24, 2011
Study for the purpose of characterizing the differences between overground walking (OW) and treadmill walking (TW) in terms of stride to stride kinematic variability by Standard Deviation (SD), and fractal dynamics by Detrended Fluctuation Analysis (DFA) and local dynamic stability. In addition, the correlations between the different variability indexes were analyzed. Participants, 20 healthy men without disabilities, performed 10 minutes each of TW and OW in a random sequence. A triaxial accelerometer recorded trunk accelerations. Kinematic variability was computed as the average SD of acceleration patterns among standardized strides. Fractal dynamics was assessed by DFA of stride intervals. Short term and long term dynamic stability were estimated by computing the maximal Lyapunov exponents (quantities characterizing the rate of separation of close trajectories) of acceleration signals. TW did not modify kinematic gait variability as compared to OW. Conversely, TW significantly modified fractal dynamics, and both short and long term local dynamic stability. No relationship was observed between variability indexes with the exception of significant negative correlation between average SD and dynamic stability in TW. Overall, treadmill induced a less correlated pattern in the stride intervals and increased gait stability, but did not modify kinematic variability.
Published by: BioMed Central Ltd (Website:http://www.biomedcentral.com)
Link to text: http://www.jneuroengrehab.com/content/8/1/12
