Article

Individuals poststroke walk at faster self-selected speeds under some nominal
level of body weight support (BWS) whereas nonimpaired individuals walk slower
after adding BWS. The purpose of this study was to determine whether increases in
self-selected overground walking speed under BWS conditions of individuals
poststroke can be explained by changes in their paretic and nonparetic ground
reaction forces (GRF). We hypothesize that increased self-selected walking speed,
recorded at some nominal level of BWS, will relate to decreased braking GRFs by
the paretic limb. We recruited 10 chronic (>12 months post-ictus, 57.5+/-9.6
y.o.) individuals poststroke and eleven nonimpaired participants (53.3+/-4.1
y.o.). Participants walked overground in a robotic device, the KineAssist Walking
and Balance Training System that provided varying degrees of BWS (0-20% in 5%
increments) while individuals self-selected their walking speed. Self-selected
walking speed and braking and propulsive GRF impulses were quantified. Out of 10
poststroke individuals, 8 increased their walking speed 13% (p=0.004) under some
level of BWS (5% n=2, 10% n=3, 20% n=3) whereas nonimpaired controls did not
change speed (p=0.470). In individuals poststroke, changes to self-selected
walking speed were correlated with changes in paretic propulsive impulses
(r=0.68, p=0.003) and nonparetic braking impulses (r=-0.80, p=0.006), but were
not correlated with decreased paretic braking impulses (r=0.50 p=0.14). This
investigation demonstrates that when individuals poststroke are provided with BWS
and allowed to self-select their overground walking speed, they are capable of
achieving faster speeds by modulating braking impulses on the nonparetic limb and
propulsive impulses of the paretic limb.
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