Energy balance of locomotion with pedal-driven watercraft |
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| Authors: | Paola Zamparo Giuseppe Carignani Luca Plaino Barbara Sgalmuzzo Carlo Capelli |
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| Institution: | 1. Corso di Laurea in Scienze Motorie , Università di Udine, Gemona del Friuli;2. Facoltà di Scienze Motorie , Università di Verona , Veronapaola.zamparo@univr.tit;4. Dipartimento di Ingegneria Gestionale Elettrica e Meccanica , Università di Udine , Udine, Italy;5. Corso di Laurea in Scienze Motorie , Università di Udine, Gemona del Friuli;6. Facoltà di Scienze Motorie , Università di Verona , Verona |
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| Abstract: | Abstract In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat and a water bike. Power output (Wdot] tot) was measured directly on the water bike by means of an instrumented chain-ring. The simultaneous assessment of oxygen uptake (Vdot]O2) allowed the computation of the “overall” efficiency of locomotion (η o = Wdot] tot / Vdot]O2). Mean η o was 0.27 (s = 0.02), which was unaffected by the speed, and was assumed to be the same for the two boats as both are semi-recumbent bicycles. For the paddle-wheel boat, Wdot] tot was then obtained from η o and measures of Vdot]O2. The power to overcome (passive) drag was calculated as Wdot] d = D · v (where D is the force measured by means of a load cell when towing the boats at given speeds). Propelling efficiency was calculated as η p = Wdot] d / Wdot] tot, which was lower with the paddle-wheel boat (mean 0.35, s = 0.01) than with the water bike (mean 0.57, s = 0.01). The observed differences in η p and Wdot] d explain why at the highest speed tested (～3 m · s?1), the energy required to cover a unit distance with the water bike is similar to that required to move the paddle-wheel boat at 1.3 m · s?1. |
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| Keywords: | Hydrodynamic resistance propelling efficiency energy cost of locomotion human-powered boats |
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