The central hypotheses are that stepping training in iSCI results in:1) greater locomotor gains as compared to non-specific interventions; 2) gains in selected impairments underlying gait dysfunction (i.e., strength and metabolic capacity and efficiency); and, 3) improvements in gait quality. To test these hypotheses, the proposed crossover, assessor-blinded, randomized clinical trial (RCT) is designed to test the effects of specificity of rehabilitation training applied early-post-stroke. In this RCT, patients > 1 year post-iSCI will be allocated to 4-6 weeks (20 session) of high-intensity stepping training or high-intensity non-specific training. Importantly, training intensity will be held constant to account for this potential confounding factor. Blinded assessments will be performed prior to and following each training paradigm. The investigators will address 3 specific aims: