 The genetic basis of muscular dystrophies is well understood, which makes gene therapy a potential treatment option in the future. A key step in developing gene therapy involves first ensuring safe delivery of genetic material into a single limb of a patient before using active treatment in the patients entire body. High-pressure, high-volume transvenous limb perfusion, in which fluid is forced under high pressure into arm and leg muscles through the veins, has shown the greatest potential as a delivery method. The purpose of this study is to determine the safety and feasibility of this method with normal saline in people who have Beckers muscular dystrophy or limb-girdle muscular dystrophy. 