Differences in uneven-surface walking characteristics: high-functioning vs low-functioning people with stroke

Background Differences in gait parameters between even- and uneven-surface walking in people with stroke (PwS) with different functional abilities remain unclear.Objectives We aimed to assess whether there are differences in the adjustments of gait parameters on uneven surfaces between PwS based on their even-surface gait speed (≥0.8 and < 0.8 m/s).Methods We calculated the root mean square (RMS) of trunk acceleration and maximum joint angles and co-contraction indexes of the lower limbs during even- and uneven-surface walking between the high-functioning group (HG) (n = 38; ≥0.8 m/s) and low-functioning group (LG) (n = 24; <0.8 m/s).Results Compared to the HG, the LG showed a greater reduction in gait speed (p = .015). Meanwhile, the RMS of trunk acceleration increased in the HG but remained unchanged in the LG on uneven surfaces. The increase in knee flexion angle during the swing phase was smaller in the LG than in the HG on uneven surfaces (p < .001). A reduction in the thigh co-contraction index during the stance phase was observed only in the HG on uneven surfaces (p = .005).Conclusions The LG responded with a conservative strategy, reducing gait speed more than the HG to maintain stability, whereas the HG exhibited decreased stability but a more flexible adaptation. The smaller increase in knee flexion during the swing phase in the LG suggests impaired motor control, while the reduction in thigh co-contraction during stance observed only in the HG indicates an adaptive response. These findings highlight that adaptation to uneven surfaces differs depending on gait ability on even surface.