Article

Safe community ambulation requires the capacity to adapt gait to
environmental changes on short notice. Reduced adaptability may contribute to an
increased risk for falls. This study investigated gait adaptability in
community-dwelling persons poststroke and sought to understand some of the
mechanisms of reduced adaptability. METHODS: Participants were 25 poststroke
persons (Functional Ambulation Categories score 5) and 25 healthy controls of
similar age. During treadmill walking, 30 obstacles were suddenly dropped in
front of the affected leg or left leg of controls. The participants had to avoid
the obstacle by either lengthening or shortening the ongoing stride. The obstacle
avoidance success rates were determined. Electromyography activity of bilateral
biceps femoris, rectus femoris, tibialis anterior, and gastrocnemius medialis
muscles was recorded as well as concomitant knee and hip angle courses and
spatial characteristics of the avoiding stride. RESULTS: Poststroke persons
demonstrated markedly decreased obstacle avoidance success rates, most
prominently under time pressure. They showed normal avoidance strategies but had
delayed and reduced electromyography responses, smaller joint angle deviations
from unperturbed walking, and smaller horizontal margins from the foot to the
obstacle. CONCLUSIONS: Even in persons who were only mildly affected by stroke,
gait adaptability may be reduced, which may place them at risk of falling.
Delayed and decreased muscle responses were identified as one possible mechanism
with diminished ability to adapt the length of the avoiding stride.
Rehabilitation interventions could focus on these impairments.

Langue : ANGLAIS