The aims of this 3-year randomized, single-blinded clinical trial are to compare the effect of high and low feedback about performance on the bedside exercise device in heart or liver transplantation recipients during the hospitalization immediately after transplantation. The hypotheses of the study are heart/liver transplantation recipients who have high feedback about performance on the bedside exercise device will progressively increase their level of exercise over the course of their hospitalization, more independent in ambulation level, better walking speed and 6-minute walk test at discharge, and better cardiorespiratory fitness at 4-8 weeks after transplantation than those who receive low feedback. The adult patients who newly receive heart or liver transplantation at National Taiwan University Hospital will be evaluated for eligibility of the study in the acute postoperative period. The study will be conducted in both the intensive care unit and ward environments. The study subjects will be randomized to either high or low feedback about performance on the bedside exercise device which uses hand/foot pedals that record exerted forces against adjustable resistances, measure repetitions of upper and lower extremity cycling movements, and give feedback about performance via a wireless internet connection. The study will also monitor the amount of daily movement activity of all subjects in this trial by using triaxial accelerometers, and the activity recognition algorithms developed by engineers and computer scientists at University of California Los Angeles. The outcome measures include level of independence for walking, walking speed, 6-minute walk test, and cardiopulmonary exercise testing by the blinded observers. The study expects to enroll at least 50 heart transplantation recipients and 60 liver transplantation recipients in 3 years. The results of this study will offer much insight into activity levels of heart or liver transplantation recipients during early postoperative period. Besides, heart transplantation recipients will receive routine phase I cardiac rehabilitation program by the physical therapists during the study but not liver transplantation recipients. We might be able to evaluate the interaction effects of routine physical therapy and UCFit exercise among our study subjects. Our data will also provide insight into just how active or inactive transplantation recipients may be and help generate ideas of organ transplantation rehabilitation program to increase their fitness-related activity prior to discharge.