The purpose of the study is to evaluate whether non-invasive stimulation over the spinal cord at the neck and/or lower back can improve walking function for people with neurologic conditions. Spinal stimulation has been used extensively for individuals with spinal cord injury, and has demonstrated improvements in function. This study will extend this work to other neurologic conditions, such as cerebral palsy and stroke, that also demonstrate similar impairments as spinal cord injury.

The primary aims of this study are to:

Aim 1: Evaluate impact of spinal stimulation on spasticity and locomotor function.

Aim 2: Investigate participant perceptions of spinal stimulation.

The investigators will be using a cross-over design study to compare intensive training only to intensive training combined with spinal stimulation. After an initial baseline period of up to 4 weeks (Phase I). Participants will have their first intervention phase of the study (Phase II). This will involve either intensive training only (Condition A) or intensive training combined with spinal stimulation (Condition B). This will be followed by a washout period with no intervention (Phase III) and then the second intervention phase (Phase IV). The second intervention phase will involve either Condition A or Condition B, whichever the participants did not received during Phase II. Phases II-IV will each last up to 8 weeks. After the intervention period is complete, the participant will be asked to come for follow-up visits up to 3 months after the intervention phases are completed (Phase V).

Inclusion Criteria:

• have a neurologic condition
• can walk 20 yards, with or without an assistive device
• have stable medical condition
• are capable of performing simple cued motor tasks and who can follow 2-3 step commands
• have ability to attend up to 5 sessions per week physical therapy sessions and testing activities
• have adequate social support to be able to participate in training and assessment sessions, up to 5 sessions per week, for the duration of up to 11 months within the study period.
• who are volunteering to be involved in this study
• can read and speak English

Exclusion Criteria:

• have significant medical disease; including uncontrolled systemic hypertension with values above 170/100 mmHg; cardiac or pulmonary disease; uncorrected coagulation abnormalities or need for therapeutic anticoagulation.
• have cardiovascular or musculoskeletal disease or injury that would prevent full participation in physical therapy intervention
• have a history of uncontrolled seizures
• have unhealed fracture or other musculoskeletal impairment that might interfere with lower extremity rehabilitation or testing activities
• are dependent on ventilation support
• have implanted stimulator (e.g. epidural stimulator, vagus nerve stimulator, pacemaker, cochlear implant, etc) or drug delivery device (e.g. baclofen pump)
• have history of orthopedic surgery in lower extremities or neurosurgery that may be a confounding factor for interpretation of the results (such as tendon transfer, tendon or muscle lengthening for spasticity management, injection therapies to lower extremity muscles, etc.) in last 12 months
• have established osteoporosis and taking medication for osteoporosis treatment.
• have rheumatic diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.)
• have active cancer