Does size of error affect the motor adaptation during split-belt treadmill walking?

We explored whether size of error affects the motor adaptation during split-belt treadmill walking in healthy adults. The split-belt treadmill has two belts that can be moved at different speeds. Subjects first walked with the two belts at the same speed (tied-belt condition) for the baseline. They then walked with one belt speed remaining at the baseline speed while the other one increased to two times the baseline speed. The increment in belt speed was sudden (creating a large movement error) for one group and incremental (creating a small error) for the other group. Finally, the belt speed returned to the baseline, called post-adaptation period. The asymmetry during post-adaptation, called aftereffect, indicates the magnitude of motor adaptation. We did not find significant difference in the magnitude of the aftereffect between the two conditions. This suggests the size of error has little effect on motor adaptation during split-belt treadmill walking.