Article

Individuals with Down syndrome (DS) show reduced gait stability that may increase
the metabolic rate (MR) during over-ground walking and alter their energetic cost
per unit distance (EC(transport)) to speed relationship. If so, the preferred
walking speed (PWS) of people with DS may coincide with their speed at minimal
EC(transport), reflecting energetic optimization. This study therefore examined
whether MR and EC(transport) during over-ground walking differ between
individuals with and without DS and whether PWS minimizes their EC(transport).
Expired gases were collected from 18 individuals with DS and 18 without during
six over-ground walking trials, each lasting 6 min, at PWS and at 0.51, 0.76,
1.01, 1.26, and 1.51 m/s. Gross- and net-MR, and gross- and net-EC(transport)
were expressed in dimensionless form. Energetically optimal walking speeds and
minimal gross- and net-EC(transport) were determined from the gross- and
net-EC(transport) to speed curves for each participant. Individuals with DS
showed higher gross-MR, net-MR, gross-EC(transport), and net-EC(transport). PWS
minimized gross-EC(transport) in participants with DS, but not in those without.
PWS did not minimize net-EC(transport) in either group. Therefore,
gross-EC(transport) minimization during over-ground walking may determine PWS
when impairments alter the gross-EC(transport) to speed relationship.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS