Gait Symmetric Adaptation and Aftereffect Through Concurrent Split-Belt Treadmill Walking and Explicit Visual Feedback Distortion

Objective: Gait asymmetry can be improved with various gait training methods. Combining split-belt treadmill walking (SB) with visual feedback distortion (VD) could enhance motor learning, improving gait symmetry adaptation and retention. This study compared step length symmetry adaptation and aftereffects between SB-only and combined explicit VD with SB, as well as between explicit VD-only and combined explicit VD with SB. Method: The 28-minute trials included three phases: a 3-minute baseline, a 10-minute adaptation, and a 15-minute post-adaptation. In the VD trial, two bars representing step lengths were displayed, with the right bar gradually decreasing by 3% to prompt participants to consciously correct their steps to match the heights of the two bars. In the SB trial, the right treadmill belt speed was incrementally increased by 5%. The VD+SB trial combined both perturbations. After the removal of these perturbations, the aftereffect of the adapted asymmetric step length was evaluated in the post-adaptation period. Results: During the adaptation period, the step length symmetry ratio shifted negatively in the SB trial, while it increased positively in the VD trial, indicating longer right steps than left. In the VD+SB trial, subjects extended their right step more than their left. Notably, the VD+SB trial demonstrated a longer aftereffect compared to both the SB-only and VD-only trials. Conclusion: The visual distortion paradigm can be explicitly applied and integrated with split-belt treadmill walking to enhance the efficacy of symmetric gait adaptation, resulting in more sustained effects on the retention of newly learned motor patterns.