The invention is directed to methods and compositions for obtaining uniform sized muscle fiber fragments for transplantation. These muscle fiber fragments are able to reconstitute into long fibers that are oriented along native muscle. The implanted muscle cells integrate with native vascular and neural network, as confirmed by histology and immunohistochemistry. This invention is particularly advantageous because autologous muscle can be harvested from a donor site, processed and injected into target sites in the operating room. The fragmented muscle fibers can be readily integrated within the host.