title: Resonance-based oscillations could describe human gait mechanics under various loading conditions.
abstract: The oscillatory behavior of the center of mass (CoM) and the corresponding ground reaction force (GRF) of human gait for various gait speeds can be accurately described in terms of resonance using a spring-mass bipedal model. Resonance is a mechanical phenomenon that reflects the maximum responsiveness and energetic efficiency of a system. To use resonance to describe human gait, we need to investigate whether resonant mechanics is a common property under multiple walking conditions. Body mass and leg stiffness are determinants of resonance; thus, in this study, we investigated the following questions: (1) whether the estimated leg stiffness increased with inertia, (2) whether a resonance-based CoM oscillation could be sustained during a change in the stiffness, and (3) whether these relationships were consistently observed for different walking speeds. Seven healthy young subjects participated in over-ground walking trials at three different gait speeds with and without a 25-kg backpack. We measured the GRFs and the joint kinematics using three force platforms and a motion capture system. The leg stiffness was incorporated using a stiffness parameter in a compliant bipedal model that best fitted the empirical GRF data. The results showed that the leg stiffness increased with the load such that the resonance-based oscillatory behavior of the CoM was maintained for a given gait speed. The results imply that the resonance-based oscillation of the CoM is a consistent gait property and that resonant mechanics may be useful for modeling human gait.
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
authors.forename: Myunghyun
authors.initials: M
authors.lastname: Lee
authors.affiliation: Korea Institute of Machinery and Materials, Daejeon, Republic of Korea.
authors.forename: Seyoung
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea. Electronic address: sukyungp@kaist.ac.kr.
authors.forename: Sukyung
authors.initials: S
authors.lastname: Park
mesh_terms: D000465:Algorithms; D001696:Biomechanical Phenomena; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D009991:Oscillometry; D013314:Stress, Mechanical; D014732:Vibration; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Center of mass; Gait speed; Leg stiffness; Load; Resonance