title: Evaluation of the Phase-Dependent Rhythm Control of Human Walking Using Phase Response Curves.
abstract: Humans and animals control their walking rhythms to maintain motion in a variable environment. The neural mechanism for controlling rhythm has been investigated in many studies using mechanical and electrical stimulation. However, quantitative evaluation of rhythm variation in response to perturbation at various timings has rarely been investigated. Such a characteristic of rhythm is described by the phase response curve (PRC). Dynamical simulations of human skeletal models with changing walking rhythms (phase reset) described a relation between the effective phase reset on stability and PRC, and phase reset around touch-down was shown to improve stability. A PRC of human walking was estimated by pulling the swing leg, but such perturbations hardly influenced the stance leg, so the relation between the PRC and walking events was difficult to discuss. This research thus examines human response to variations in floor velocity. Such perturbation yields another problem, in that the swing leg is indirectly (and weakly) perturbed, so the precision of PRC decreases. To solve this problem, this research adopts the weighted spike-triggered average (WSTA) method. In the WSTA method, a sequential pulsed perturbation is used for stimulation. This is in contrast with the conventional impulse method, which applies an intermittent impulsive perturbation. The WSTA method can be used to analyze responses to a large number of perturbations for each sequence. In the experiment, perturbations are applied to walking subjects by rapidly accelerating and decelerating a treadmill belt, and measured data are analyzed by the WSTA and impulse methods. The PRC obtained by the WSTA method had clear and stable waveforms with a higher temporal resolution than those obtained by the impulse method. By investigation of the rhythm transition for each phase of walking using the obtained PRC, a rhythm change that extends the touch-down and mid-single support phases is found to occur.
authors.affiliation: Department of Mechanical Engineering and Intelligent Systems, The University of Electro-communications, Chofu, Tokyo, Japan.|Japan Science and Technology Agency (JST), CREST, Chiyoda-ku, Tokyo, Japan.
authors.forename: Tetsuro
authors.identifier: 0000-0003-2964-5227
authors.initials: T
authors.lastname: Funato
authors.affiliation: Department of Energy and Mechanical Engineering, Doshisha University, Kyotanabe-shi, Kyoto, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Japan Science and Technology Agency (JST), CREST, Chiyoda-ku, Tokyo, Japan.|Department of Aeronautics and Astronautics, Kyoto University, Nishikyo-ku, Kyoto, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Aoi
authors.affiliation: Department of Applied Analysis and Complex Dynamical Systems, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Imai
authors.affiliation: Japan Science and Technology Agency (JST), CREST, Chiyoda-ku, Tokyo, Japan.|Department of Applied Analysis and Complex Dynamical Systems, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Aoyagi
authors.affiliation: Japan Science and Technology Agency (JST), CREST, Chiyoda-ku, Tokyo, Japan.|Department of Energy and Mechanical Engineering, Doshisha University, Kyotanabe-shi, Kyoto, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Tomita
authors.affiliation: Japan Science and Technology Agency (JST), CREST, Chiyoda-ku, Tokyo, Japan.|Department of Aeronautics and Astronautics, Kyoto University, Nishikyo-ku, Kyoto, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsuchiya
mesh_terms: D000054:Acceleration; D001696:Biomechanical Phenomena; D019295:Computational Biology; D005684:Gait / Q000502:physiology; D006801:Humans; D007866:Leg; D008297:Male; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology; D010507:Periodicity; D016138:Walking / Q000502:physiology*; D055815:Young Adult