In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat and a water bike. Power output (W-tot) was measured directly on the water bike by means of an instrumented chain-ring. The simultaneous assessment of oxygen uptake (VO2) allowed the computation of the "overall" efficiency of locomotion (eta(o)=W-tot/VO2). Mean eta(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, W-tot was then obtained from eta(o) and measures of VO2. The power to overcome (passive) drag was calculated as W-d=D center dot upsilon (where D is the force measured by means of a load cell when towing the boats at given speeds). Propelling efficiency was calculated as eta(p)=W-d/W-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 eta(p) and W-d explain why at the highest speed tested (similar to 3 m center dot 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 center dot s(-1).

Energy balance of locomotion with pedal-driven watercrafts

ZAMPARO, Paola;CAPELLI, Carlo
2008-01-01

Abstract

In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat and a water bike. Power output (W-tot) was measured directly on the water bike by means of an instrumented chain-ring. The simultaneous assessment of oxygen uptake (VO2) allowed the computation of the "overall" efficiency of locomotion (eta(o)=W-tot/VO2). Mean eta(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, W-tot was then obtained from eta(o) and measures of VO2. The power to overcome (passive) drag was calculated as W-d=D center dot upsilon (where D is the force measured by means of a load cell when towing the boats at given speeds). Propelling efficiency was calculated as eta(p)=W-d/W-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 eta(p) and W-d explain why at the highest speed tested (similar to 3 m center dot 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 center dot s(-1).
2008
locomotory tools; aquatic environment; efficiency of locomotion; cycling
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/307891
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