Gene expression of myogenic and fibrotic markers is up regulated, while metabolic markers are down regulated in the injured muscle. TA muscles from SED and RUN (one week of running) injured muscles were harvested two weeks post-injury. Tissue samples comprised of defect area and the remaining muscle were assayed for gene expression of A) Embryonic heavy chain myosin (eMHC), B) Collagen I (Col I), C) Transforming growth factor-β1 (TGF-β1), D) Silent mating type information regulation 2 homolog-1 (SIRT-1) and E) Peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α). Note: All gene expression data was normalized to SED uninjured. Values are mean ± SEM. n = 3-5 muscles/group; # denotes ≠ injured; p < 0.05.