Myoblasts are a type of stem cells that exist in muscles.

They're in embryo, before developing into muscle cells in growth. (called myocytes)

In myoblast transfer, millions of immature muscle cells are injected into an affected muscle. The goal of the treatment is to promote the growth of the injected cells, replacing the defective host cells with healthy new ones

The scientific name for a muscle cell is a myocyte. Myocytes are also sometimes called muscle fibers. They are long, tube shaped, cells that develop from myoblasts.