title: The pendular mechanism does not determine the optimal speed of loaded walking on gradients.
abstract: The pendular mechanism does not act as a primary mechanism in uphill walking due to the monotonic behavior of the mechanical energies of the center of mass. Nevertheless, recent evidence shows that there is an important minimization of energy expenditure by the pendular mechanism during walking on uphill gradients. In this study, we analyzed the optimum speed (OPT) of loaded human walking and the pendulum-like determining variables (Recovery R, Instantaneous pendular re-conversion Rint, and Congruity percentage %Cong). Ten young men walked on a treadmill at five different speeds and at three different treadmill incline gradients (0, +7 and +15%), with and without a load carried in their backpacks. We used indirect calorimetry and 3D motion analysis, and all of the data were analyzed by computational algorithms. Rint increased at higher speeds and decreased with increasing gradient. R and %Cong decreased with increasing gradient and increased with speed, independent of load. Thus, energy conversion by the pendular mechanism during walking on a 15% gradient is supported, and although this mechanism can explain the maintenance of OPT at low walking speeds, the pendular mechanism does not fully explain the energy minimization at higher speeds.
authors.affiliation: Exercise Research Laboratory, Federal University of Rio Grande do Sul, 90690-200 Porto Alegre, Brazil.
authors.forename: Natalia Andrea
authors.initials: NA
authors.lastname: Gomeñuka
authors.affiliation: PDU Biomechanics, Centro Universitario de Paysandú, Universidad de la Republica, Paysandú, Uruguay.
authors.forename: Renata Luisa
authors.initials: RL
authors.lastname: Bona
authors.affiliation: Exercise Research Laboratory, Federal University of Rio Grande do Sul, 90690-200 Porto Alegre, Brazil.
authors.forename: Rodrigo Gomes
authors.initials: RG
authors.lastname: da Rosa
authors.affiliation: Exercise Research Laboratory, Federal University of Rio Grande do Sul, 90690-200 Porto Alegre, Brazil. Electronic address: leonardo.tartaruga@ufrgs.br.
authors.forename: Leonardo Alexandre
authors.initials: LA
authors.lastname: Peyré-Tartaruga
mesh_terms: D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D005080:Exercise Test; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
keywords: Congruity percentage; Gait; Load; Recovery; Slope