 All patients will participate in a locomotor training program. Patients will be randomly assigned to either training at self-selected treadmill velocity or at a normal walking velocity. Patients will have 45 training sessions over 9 weeks. Each training session will include 30 minutes of walking. Interim testing of rated depression, spatial-temporal parameters of walking, MRI, and walking activity will occur through the 9-week training period. Post-testing will occur within 2 days of the last training session and at a 1 month after completion of the training. During the month following long-term training, patients will be instructed to return to their self-selected routine activities of daily living. 