Foot placement control and gait instability among people with stroke.
Gait instability is a common problem following stroke, as evidenced by increases in fall risk and fear of falling. However, the mechanism underlying gait instability is currently unclear. We recently found that young, healthy humans use a consistent gait stabilization strategy of actively controlling their mediolateral foot placement based on the concurrent mechanical state of the stance limb. In the present work, we tested whether people with stroke (n = 16) and age-matched controls (n = 19) used this neuromechanical strategy. Specifically, we used multiple linear regressions to test whether (1) swing phase gluteus medius (GM) activity was influenced by the simultaneous state of the stance limb and (2) mediolateral foot placement location was influenced by swing phase GM activity and the mechanical state of the swing limb at the start of the step. We found that both age-matched controls and people with stroke classified as having a low fall risk (Dynamic Gait Index [DGI] score >19) essentially used the stabilization strategy previously described in young controls. In contrast, this strategy was disrupted for people with stroke classified as higher fall risk (DGI </=19), particularly for steps taken with the paretic limb. These results suggest that a reduced ability to appropriately control foot placement may contribute to poststroke instability.
['Dean|Jesse C|JC|', 'Kautz|Steven A|SA|']
D000368:Aged D001696:Biomechanical Phenomena D002908:Chronic Disease D005260:Female D005528:Foot D005684:Gait D020233:Gait Disorders, Neurologic D006801:Humans D008297:Male D008875:Middle Aged D009119:Muscle Contraction D018482:Muscle, Skeletal D020521:Stroke D000071939:Stroke Rehabilitation D016138:Walking
foot placement stroke stability balance biomechanics frontal plane kinematics motor control muscle activity walking