Article

Step length asymmetry (SLA) is a common hallmark of gait poststroke.
Though conventionally viewed as a spatial deficit, SLA can result from
differences in where the feet are placed relative to the body (step position
strategy), the timing between foot strikes (step time strategy), or the velocity
of the body relative to the feet (step velocity strategy). OBJECTIVE: The goal of
this study was to characterize the relative contributions of each of these
strategies to SLA. METHODS: We developed an analytical model that parses SLA into
independent step position, step time, and step velocity contributions. This model
was validated by reproducing SLA values for 25 healthy participants when their
natural symmetric gait was perturbed on a split-belt treadmill moving at either a
2:1 or 3:1 belt-speed ratio. We then applied the validated model to quantify step
position, step time, and step velocity contributions to SLA in 15 stroke
survivors while walking at their self-selected speed.
RESULTS: SLA was predicted
precisely by summing the derived contributions, regardless of the belt-speed
ratio. Although the contributions to SLA varied considerably across our sample of
stroke survivors, the step position contribution tended to oppose the other
2-possibly as an attempt to minimize overall SLA. CONCLUSIONS: Our results
suggest that changes in where the feet are placed or changes in interlimb timing
could be used as compensatory strategies to reduce overall SLA in stroke
survivors. These results may allow clinicians and researchers to identify
patient-specific gait abnormalities and personalize their therapeutic approaches
accordingly.
CI - (c) The Author(s) 2015.

Langue : ANGLAIS