title: Walking dynamic similarity induced by a combination of Froude and Strouhal dimensionless numbers: Modela-w.
abstract: The aim of this study was to assess the accuracy of a new dimensionless number associating Froude (Nfr) and Strouhal (Str) called Modela-w to induce walking dynamic similarity among humans of different sizes. Nineteen subjects walked in three experimental conditions: (i) constant speed, (ii) similar speed (Nfr) and (iii) similar speed and similar step frequency (Modela-w). The dynamic similarity was evaluated from scale factors computed with anthropometric, temporal, kinematic and kinetic data and from the decrease of the variability of the parameters expressed in their dimensionless form. Over a total of 36 dynamic parameters, dynamic similarity from scale factors was met for 11 (mean r = 0.51), 22 (mean r = 0.52) and 30 (mean r = 0.69) parameters in the first, the second and the third experimental conditions, respectively. Modela-w also reduced the variability of the dimensionless preceding parameters compared to the other experimental conditions. This study shows that the combination of Nfr and Str called Modela-w ensures dynamic similarity between different-sized subjects and allows scientists to impose similar experimental conditions removing all anthropometric effects.
authors.affiliation: Université de Toulouse, UPS, PRISSMH, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France. Electronic address: david.villeger@univ-tlse3.fr.
authors.forename: David
authors.initials: D
authors.lastname: Villeger
authors.affiliation: Université de Toulouse, UPS, PRISSMH, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France.
authors.forename: Antony
authors.initials: A
authors.lastname: Costes
authors.affiliation: Université de Toulouse, UPS, PRISSMH, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France; CNRS, LAAS, 7 avenue du colonel Roche, F-31077 Toulouse, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Watier
authors.affiliation: Université de Toulouse, UPS, PRISSMH, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France; Université de Toulouse, UPS, Centre de Recherche sur la Cognition animale, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France; CNRS, Centre de Recherche sur la Cognition Animale, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Moretto
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Center of mass; Dynamic similarity; Similar frequency; Similar speed; Spring mass model