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First published online October 5, 2007
Journal of Experimental Biology 210, 3513-3524 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.000992

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Reappraisal of the comparative cost of human locomotion using gait-specific allometric analyses

Jonas Rubenson^1,*, Denham B. Heliams², Shane K. Maloney³, Philip C. Withers⁴, David G. Lloyd¹ and Paul A. Fournier¹

¹ School of Human Movement and Exercise Science, The University of Western Australia, Crawley, WA 6009, Australia
² Fauna Technology, PO Box 558, Gosnells, WA 6990, Australia
³ Physiology, School of Biomedical, Biomolecular and Chemical Sciences, The University of Western Australia, Crawley, WA 6009, Australia
⁴ School of Animal Biology, The University of Western Australia, Crawley, WA 6009, Australia

View larger version (15K): [in this window] [in a new window]   Fig. 1. Double logarithmic plot of the net energy cost of human running (Erun) versus body mass calculated from the slope method (A) and subtraction method (B) (see Materials and methods for explanation). The shaded circles represent human data from 20 previously published sources (see Table 1A and Table 1B for corresponding data), and the solid circle represents the mean value from these studies. The solid line in A and the broken line in B correspond to Erun predicted from the allometric equation of Taylor et al. (Taylor et al., 1982) (Eqn 1). The solid line in B corresponds to Erun predicted from the new allometric equation from the present study (Eqn 2).

View larger version (12K): [in this window] [in a new window]   Fig. 2. Double logarithmic plot of the net energy cost of running (Erun) versus body mass for humans and other mammalian and avian species. The shaded circles represent human data from 20 previously published sources (calculated from the subtraction method; see Materials and methods) (Table 1B), and the solid circle represents the mean value from these studies. The solid diamonds represent the other animals (see Table 3) used to generate the allometric equation for Erun using the subtraction method (Eqn 2). The solid line corresponds to the predicted Erun from this equation. For comparison, we have included the data points used by Taylor et al. (Taylor et al., 1982) (shaded diamonds; used to generate their allometric equation for Erun (Eqn 1; slope method). The broken line corresponds to the predicted Erun from Eqn 1.

View larger version (13K): [in this window] [in a new window]   Fig. 3. Double logarithmic plot of the net energy cost of walking versus body mass (calculated from the subtraction method; see Materials and methods). The shaded circles represent human data from 20 previously published sources (calculated from the subtraction method, see Materials and methods) (Table 2), and the solid circle represents the mean value from these studies. The solid diamonds represent the other animals (see Table 4) used to generate the allometric equations for the net cost of walking. The solid line represents the predicted net cost of walking from the allometric equation based on animals for which either a minimum net cost of walking could be assessed or for which the net cost of walking was measured at a self-selected walking speed (Ewalk; Eqn 4). The broken line represents the predicted net cost of walking from the allometric equation based only on animals for which a minimum net cost of walking could be assessed (Ewalk,min; Eqn 3).

View larger version (12K): [in this window] [in a new window]   Fig. 4. Histogram of the percentage difference between the measured and allometrically predicted net cost of running (Erun) using (A) the animal data from Taylor et al. (Taylor et al., 1982) (N=95) and the allometric equation (Eqn 1) developed in their study (where Erun is computed using the slope method; see Materials and methods) and (B) 31 animals for which Erun was computed using the subtraction method and the allometric equation developed from these data (Eqn 2). The position of the mean human Erun based on the subtraction method from 20 previously published studies is represented by the black bars.

View larger version (14K): [in this window] [in a new window]   Fig. 5. The predicted net cost of running (Erun) and walking (Ewalk) using the new allometric equation of the net cost of running (Eqn 2; solid line) and the new allometric equation of the net cost of walking (Eqn 4; broken line). The point where these relationships intersect (20 kg) represents the theoretical mass where the net cost of walking and running are equivalent. Above this mass, the net cost of walking is predicted to be greater than the net cost of running, and below this mass the opposite is predicted.