Impact of unilateral knee restraint on symmetry adaptation and double-support phase dynamic stability during split-belt walking.

The split-belt treadmill task is an effective tool for studying walking adaptation, particularly the symmetry adaptation of spatiotemporal parameters such as step length and double support time. This study aimed to evaluate the relationship between symmetry adaptation of spatiotemporal parameters and dynamic stability during the double-support phase in split-belt walking. We hypothesized that restraining fast-side knee extension, which is necessary for step lengthening during adaptation, would decrease dynamic stability during the double-support phase. Ten able-bodied male participants performed split-belt walking tasks under three conditions: control, fast-side knee restraint, and slow-side knee restraint. Our findings revealed that slow-side knee restraint disrupted symmetry in double support time and significantly decreased stability on the fast side during the early and late adaptation phases. Contrary to our hypothesis, fast-side knee restraint did not have a statistically significant effect on dynamic stability or symmetry. These results suggest that decreased dynamic stability during the double-support phase, particularly due to limitations in the movement of the trailing leg, may hinder the adaptation process. This study highlights the importance of dynamic stability control during the double-support phase for successful walking adaptation. Future studies with larger sample sizes and varying speed conditions are recommended to generalize these findings and develop targeted interventions to improve walking adaptability and dynamic stability.