title: Energy cost and mechanical efficiency of riding a human-powered recumbent bicycle.
abstract: When dealing with human-powered vehicles, it is important to quantify the capability of converting metabolic energy in useful mechanical work by measuring mechanical efficiency. In this study, net mechanical efficiency (eta) of riding a recumbent bicycle on flat terrain and at constant speeds (v, 5.1-10.0 m/s) was calculated dividing mechanical work (w, J/m) by the corresponding energy cost (C(c), J/m). w and C(c) increased linearly with the speed squared: w = 9.41 + 0.156 . v(2); C(c) = 39.40 + 0.563 . v(2). eta was equal to 0.257 +/- 0.0245, i.e. identical to that of concentric muscular contraction. Hence, i) eta seems unaffected by the biomechanical arrangement of the human-vehicle system; ii) the efficiency of transmission seems to be close to 100%, suggesting that the particular biomechanical arrangement does not impair the transformation of metabolic energy in mechanical work. When dealing with human-powered vehicles, it is important to quantify mechanical efficiency (eta) of locomotion. eta of riding a recumbent bicycle was calculated dividing the mechanical work to the corresponding energy cost of locomotion; it was practically identical to that of concentric muscular contraction (0.257 +/- 0.0245), suggesting that the power transmission from muscles to pedals is unaffected by the biomechanical arrangement of the vehicle.
authors.affiliation: Department of Neurological and Visual Sciences, School of Exercise Sciences, University of Verona, Verona, Italy. carlo.capelli@univr.it
authors.forename: Carlo
authors.initials: C
authors.lastname: Capelli
authors.forename: Luca Paolo
authors.initials: LP
authors.lastname: Ardigo
authors.forename: Federico
authors.initials: F
authors.lastname: Schena
authors.forename: Paola
authors.initials: P
authors.lastname: Zamparo
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D004734:Energy Metabolism / Q000502:physiology*; D004867:Equipment Design; D006801:Humans; D008875:Middle Aged