Twenty patients with progressive MS (primary and secondary) of high disability level (EDSS 6.0-8.0) will be recruited to participate in this study. Both primary and secondary MS patients will be included due to similarities in disease progression and a lack of available alternative treatments for this population. Patients will be randomized to either the TBRST or BWSTT intervention; there will be 10 patients in each group. Patients in the TBRST program will train using the Nustep (TRS 4000) recumbent cross trainer. The recumbent cross trainer allows patients to move their legs in a natural stepping motion with bilateral reciprocal movement of the arms from a seated position. Foot straps, leg stabilizers and hand stabilizers may be used for added control and proper body alignment when necessary. Patients in the BWSTT group will exercise using the Woodway Loco-system which allows a portion of the patient's body-weight to be off-loaded by an overhead pulley system. Treadmill therapists will guide the patients' legs through a proper gait motion and assist with lower limb control.