Stem cells discovered in populations of Satellite Cells.

http://www.sciencedaily.com/releases/2009/03/090305121655.htm

Muscular Dystrophy is a disease caused by the inability of the body to produce dystrophin which is needed to sustain muscle cells. Satellite Cells are found around the muscle fibers. They can divide in specialized cells that can repair stressed muscle fibers. Researchers have learned there are stem cells within the Satellite cells can sustained the population of the Satellite cells which is important in keeping the muscle functional.
After Researchers injected Satellite Cells into a mouse's Satellite cells population they learned the injected Satellite Cells produced more Satellite Cells improving muscle repair and sustaining the population of Satellite cells in the region.

The only problem with this is you would need to keep injected satellite cells into the patient in order for the individual to maintain his muscles because of the lack of the protein dystrophin.