Adapting gait with asymmetric visual feedback affects deadaptation but not adaptation in healthy young adults

Abstract

Split-belt treadmill walking allows researchers to understand how new gait patterns are acquired. Initially, the belts move at two different speeds, inducing asymmetric step lengths. As people adapt their gait on a split-belt treadmill, left and right step lengths become more symmetric over time. Upon returning to normal walking, step lengths become asymmetric in the opposite direction, indicating deadaptation. Then, upon re-exposure to the split belts, step length asymmetry is less than the asymmetry at the start of the initial exposure, indicating readaptation. Changes in step length symmetry are driven by changes in step timing and step position asymmetry. It is critical to understand what factors can promote step timing and position adaptation and therefore influence step length asymmetry. There is limited research regarding the role of visual feedback to improve gait adaptation. Using visual feedback to promote the adaptation of step timing or position may be useful of understanding temporal or spatial gait impairments. We measured gait adaptation, deadaptation, and readaptation in twenty-nine healthy young adults while they walked on a split-belt treadmill. One group received no feedback while adapting; one group received asymmetric real-time feedback about step timing while adapting; and the last group received asymmetric real-time feedback about step position while adapting. We measured step length difference (non-normalized asymmetry), step timing asymmetry, and step position asymmetry during adaptation, deadaptation, and readaptation on a split-belt treadmill. Regardless of feedback, participants adapted step length difference, indicating that walking with temporal or spatial visual feedback does not interfere with gait adaptation. Compared to the group that received no feedback, the group that received temporal feedback exhibited smaller early deadaptation step position asymmetry (p = 0.005). There was no effect of temporal or spatial feedback on step timing. The feedback groups adapted step timing and position similarly to walking without feedback. Future work should investigate whether asymmetric visual feedback also results in typical gait adaptation in populations with altered step timing or position control.

Habitual exercise evokes fast and persistent adaptation during split-belt walking

“…The changes in the asymmetry between left and right step lengths, or step length asymmetry (SLA) is one measure used to track how a person's gait pattern adapts in response to a continuous perturbation. As a robust measure of gait adaptation, SLA is observable with the unaided eye, is sensitive to experimental manipulations, and persists even after the split-belt perturbation is removed [1][2][3][4]10]. In line with upper extremity motor adaptation [11], adaptation of SLA during split-belt walking occurs at two distinct and interacting timescales-a fast component that adapts rapidly and a slow component that adapts more gradually [12][13][14][15].…”

“…When a person encounters a perturbation, such as when walking on an icy or uneven surface, they must adapt their walking patterns to avoid falling which can be achieved using different strategies. While prior research suggests that visual feedback [1,2], focus of attention [3,4], and neurological injury [5][6][7] can affect aspects of walking adaptation, how or if individual factors related to overall physical activity might influence walking adaptation strategies needs further evidence.…”

Habitual exercise evokes fast and persistent adaptation during split-belt walking

“…The changes in the asymmetry between left and right step lengths, or step length asymmetry (SLA) is one measure used to track adaptation. SLA robustly changes during split-belt walking, shows an aftereffect after the split-belt perturbation is removed, is observable with the unaided eye, and is sensitive to experimental manipulations (3–7). In line with upper extremity motor adaptation (8), adaptation of SLA during split-belt walking occurs at two distinct rates – a fast component that adapts rapidly and a slow component that adapts more gradually (9–12).…”