Background: Fatigue or tiredness is a major problem in children, adolescents and adults receiving intensive chemotherapy for cancer and in those undergoing hematopoietic stem cell transplantation (HSCT). While exercise is good for reducing fatigue, these patients are often too sick to participate in regular exercise sessions. A unique, potentially effective type of exercise is individualized yoga. Yoga is particularly good since it can be tailored to be more or less intensive depending on how the child is feeling. The investigators have previously performed a feasibility study of yoga in children admitted to the hospital receiving very intensive chemotherapy or HSCT and found that our program of yoga is doable. The investigators also found children and their parents like the program.