Article

Post-stroke hemiparetic walking is typically asymmetric. Assessment of symmetry
is often performed at either self-selected or fastest-comfortable walking speeds
to gain insight into coordination deficits and compensatory mechanisms. However,
how walking speed influences the level of asymmetry is unclear. This study
analyzed relative changes in paretic and non-paretic leg symmetry to assess
whether one speed is more effective at highlighting asymmetries in hemiparetic
walking and whether there is a systematic effect of speed on asymmetry. Forty-six
subjects with chronic hemiparesis walked at their self-selected and
fastest-comfortable speeds on an instrumented split-belt treadmill. Relative
proportions (paretic leg value/(paretic+non-paretic leg value)) were computed at
each speed for step length (PSR), propulsion (PP), and joint moment impulses at
the ankle and hip. Thirty-six subjects did not change their step length symmetry
with speed, while three subjects changed their step length values toward
increased asymmetry and seven changed toward increased symmetry. Propulsion
symmetry did not change uniformly with speed for the group, with 15 subjects
changing their propulsion values toward increased asymmetry while increasing
speed from their self-selected to fastest-comfortable and 11 decreasing the
asymmetry. Both step length and propulsion symmetry were correlated with ankle
impulse proportion at self-selected and fastest-comfortable speed (cf., hip
impulse proportion), but ratios (self-selected value/fastest-comfortable value)
of the proportion measures (PSR and PP) showed that neither step length nor
propulsion symmetry correlated with the ankle impulse proportions. Thus, the
individual kinetic mechanisms used to increase speed could not be predicted from
PSR or PP.
CI - Copyright 2009 Elsevier B.V. All rights reserved.

Langue : ANGLAIS