This is a non-randomized pilot study to evaluate the safety and feasibility of an exercise program in hospitalized infants with single ventricle physiology. Following the Norwood procedure, the intervention will be administered for up to 21 days or until discharge, whichever comes first. Data will be collected daily during hospitalization and at a follow-up visit at 3 months of age. Sources of data will include medical record review. Twenty subjects will be enrolled at three Pediatric Heart Network study sites (Utah Primary Children's Hospital, Children's Hospital of Philadelphia and Texas Children's Hospital). Subjects will be recruited following Institutional Review Board (IRB) approval at each institution and parental/legal guardian consent.