Article

Stroke survivors often have a slow, asymmetric walking pattern. They also walk
with a higher metabolic cost than healthy, age-matched controls.
It is often
assumed that spatial-temporal asymmetries contribute to the increased metabolic
cost of walking poststroke. However, elucidating this relationship is made
challenging because of the interdependence between spatial-temporal asymmetries,
walking speed, and metabolic cost. Here, we address these potential confounds by
measuring speed-dependent changes in metabolic cost and implementing a recently
developed approach to dissociate spatial versus temporal contributions to
asymmetry in a sample of stroke survivors. We used expired gas analysis to
compute the metabolic cost of transport (CoT) for each participant at 4 different
walking speeds: self-selected speed, 80% and 120% of their self-selected speed,
and their fastest comfortable speed. We also computed CoT for a sample of age-
and gender-matched control participants who walked at the same speeds as their
matched stroke survivor. Kinematic data were used to compute the magnitude of a
number of variables characterizing spatial-temporal asymmetries. Across all
speeds, stroke survivors had a higher CoT than controls. We also found that our
sample of stroke survivors did not choose a self-selected speed that minimized
CoT, contrary to typical observations in healthy controls. Multiple regression
analyses revealed negative associations between speed and CoT and a positive
association between asymmetries in foot placement relative to the trunk and CoT.
These findings suggest that interventions designed to increase self-selected
walking speed and reduce foot-placement asymmetries may be ideal for improving
walking economy poststroke.

Langue : ANGLAIS