Pelvic motion is of great importance when walking, and have thus to be taken into account while developing rehabilitation robotics. This paper describes the implementation of a pelvic motion amplitude prediction model on a pelvic orthosis and tests on valid subjects. Furthermore over ground versus treadmill walking was also performed. For comparison averaged pelvic trajectories were tested against subject’s own trajectories. The results showed that the model was valid and that over ground walking resulted in smaller forces applied on the subject.