In order to evaluate the effectiveness of a robotic trainer, NaTUre-gaits (Natural and TUneable rehabilitation gait system), four healthy and one spinal cord injury (SCI) subjects have participated in the walking experiment. The comparison between robotic-assisted overground walking with ground contact and totally robotic-assisted walking without ground contact is conducted via EMG analysis. Furthermore, in order to highlight the effect of overground walking, an insole force system is developed to measure the ground reaction force (GRF). An initial study is carried out for the estimation of the relationship between GRF and EMG, which is useful to future integration of the active control on NaTUre-gaits. The initial results show that the performance of overground walking with the gait system is not only comparable to manual assistance, but it also provides natural ground contacts.