RecruitingClinical trialBioFLO for Respiratory Recovery in SCIAcute intermittent hypoxia (AIH) involves brief (1 min), repeated episodes (\~15) of breathing low oxygen air to stimulate spinal neuroplasticity. Animal and human studies show that AIH improves motor function after spinal cord injury, particularly with slightly increased carbon dioxide (hypercapnic AIH; AIHH) and task-specific training. Using a double blind cross-over design, the study will test whether AIHH improves breathing more than AIH and whether specific genetic variations are related to individuals' intervention responses.