title: Kinematics of center of mass and center of pressure predict friction requirement at shoe-floor interface during walking.
abstract: We aimed to determine whether inclination angles of the line connecting the whole body center of mass (COM) to the center of pressure (COP) (COM-COP angle) help predict the required coefficient of friction (RCOF) in young adult males during the weight acceptance and push-off phases in transient movements such as turning, gait termination and initiation, and steady-state movements such as straight walking. Seventeen healthy young adult males were asked to (1) walk in a straight line, (2) turn 60° with either foot (step and spin turns), and (3) initiate and terminate walking on a dry level floor. Peak absolute values of the ratio between resultant horizontal and vertical ground reaction forces during the weight acceptance and push-off phases (RCOFh and RCOFt, respectively) were calculated. COM-COP angles θh and θt at the instant of RCOFh and RCOFt, respectively, were also calculated. Bivariate regression analysis demonstrated that the |θh| and |θt| tangents were significant predictors of RCOFh (R = 0.878; R(2) = 0.770; p<0.001) and RCOFt (R = 0.918; R(2) = 0.843; p<0.001), respectively. The results suggest that COM and COP kinematics (i.e., the COM-COP angle) serve as a predictor of friction requirement during the weight acceptance and push-off phases in steady-state movements such as straight walking and transient movements such as turning as well as gait termination and initiation.
authors.affiliation: Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan. yamatake@gdl.mech.tohoku.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Masaru
authors.initials: M
authors.lastname: Yano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onodera
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hokkirigawa
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D001696:Biomechanical Phenomena; D005430:Floors and Floorcoverings; D017276:Friction / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011312:Pressure; D012044:Regression Analysis; D012775:Shoes; D055815:Young Adult