Open Access Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Do horizontal propulsive forces influence the nonlinear structure of locomotion? | Journal of NeuroEngineering and Rehabilitation BioMed Central Short report Open Access Do horizontal propulsive forces influence the nonlinear structure of locomotion Max J Kurz 1 and Nicholas Stergiou2 Address laboratory of Integrated Physiology University of Houston Department of Health and Human Performance Houston Texas USA and 2HPER Biomechanics Laboratory University of Nebraska at Omaha School of HPER Omaha Nebraska USA Email Max J Kurz - mkurz@ Nicholas Stergiou - nstergiou@ Corresponding author Published 15 August 2007 Received 13 October 2006 Journal of NeuroEngineering and Rehabilitation 2007 4 30 doi 1743-0003-4-30 Accepted 15 August 2007 This article is available from http content 4 1 30 2007 Kurz and Stergiou licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Several investigations have suggested that changes in the nonlinear gait dynamics are related to the neural control of locomotion. However no investigations have provided insight on how neural control of the locomotive pattern may be directly reflected in changes in the nonlinear gait dynamics. Our simulations with a passive dynamic walking model predicted that toe-off impulses that assist the forward motion of the center of mass influence the nonlinear gait dynamics. Here we tested this prediction in humans as they walked on the treadmill while the forward progression of the center of mass was assisted by a custom built mechanical horizontal actuator. Methods Nineteen participants walked for two minutes on a motorized treadmill as a horizontal actuator assisted the forward translation of the center of mass during the stance phase. All subjects walked at a self-select speed that had a .