RecruitingDevice studyTPAD for Recovery of Standing After Severe SCIThe purpose of this study is to investigate how standing and sitting balance control is altered after spinal cord injury (SCI) and how a new type of robotic assistive device may be used to improve muscle function. This device is called the Tethered Pelvic Assist Device, or TPAD. The main aims are to: 1\. Examine muscle activation patterns generated during different types of standing in spinal cord injured individuals using robotic assistance or self-assistance for balance 2 and 3. Examine the effectiveness of robotic-assisted stand training in the improvement of posture control during different types of standing and sitting in spinal cord injured individuals. Participants will be placed into one of 5 groups based on a physical classification of their spinal cord injury: Group 1: * Individuals with SCI that can stand independently * Will receive TPAD training * Will undergo standing, posture, sitting, and stepping assessments * Participation in this group will last about six months Group 2: * Individuals with SCI that cannot stand independently * Will receive TPAD training * Will undergo standing, posture, sitting, and stepping assessments * Participation in this group will last about 6 months Group 3: * Individuals with SCI that can stand independently * Will undergo standing and posture assessments * Participation in this group will last about 2 weeks Group 4: * Individuals with SCI that cannot stand independently * Will undergo standing and posture assessments * Participation in this group will last about 2 weeks Group 5: * Individuals without a SCI * Will undergo standing, posture, and sitting assessments * Participation in this group will last about 2 weeks