Multimodal Exercises to Improve Leg Function After Spinal Cord Injury

Many people with spinal cord injury (SCI) retain at least some movement below their injury, but their muscles often have a 'mind of their own'. Typical exercise programs focus on keeping muscles strong and flexible, but don't usually focus on helping patients control their muscles. The investigators' exercise research study will compare two different programs with the specific goal of improving conscious control of patients' muscles below the injury. This study focuses on those with 'chronic' SCI - the injury occurred at least one year prior to enrolling. This is a single center study taking place in the Bronx, NY. The first phase of the study will be observational - the investigators will analyze which nerve connections might remain partially intact through the injury (even if the nerves aren't consciously controlled). Participants with all severity of SCI may participate in this first phase. The second phase of the study will involve people who retain at least slight ability to move their legs and the ability to move the arms against gravity. Each person will undergo two different exercise rehabilitation strategies: weight-supported treadmill training; and balance training combined with skilled arm or hand exercises. The investigators will compare the effects of these exercise programs on a variety of outcomes, including gait speed, balance, strength, and muscle activation in response to brain stimulation. The investigators hypothesize that participants with chronic SCI undergoing combined balance/arm/hand training will show improved outcomes when compared to traditional gait or balance training.