Fixating the pelvis in the horizontal plane affects gait characteristics.

In assistive devices for neuro-rehabilitation, natural human motions are partly restricted by the device. This may affect the normality of walking during training. This research determines effects on gait of fixating the pelvis translations in the horizontal plane during treadmill walking. Direct effects on the motion of the pelvis and external forces acting on the pelvis were measured. Several gait descriptors (step parameters, trunk angles and a ground reaction force parameter) were defined and measured to indicate changes. We observed the effect of the pelvis fixation on these parameters while varying gait velocity (0.35, 0.60 and 0.90 m/s). It was shown that the fixation caused a reduction of step width by 33%, and an increase of step length of 19%. Sagittal and coronal trunk rotations changed with +68% and -54% respectively. The fixation also significantly changed the effect of speed on most descriptors. It can therefore be concluded that a fixation of the pelvis severely affects gait dynamics and that it should be avoided if natural walking should be possible during training.