Representative photomicrographs of myosin heavy chain (MHC) immunohistochemistry of IRR-control (A, B, C, D and E) and 21 day-stimulated rat tibialis anterior muscles (F, G, H, I and J). A and F, immunostains for MHCI (clone BA-D5); B and G, immunostains for MHCIIa (clone SC-71); C and H, immunostains for all MHCs except MHCIId(x) (clone BF-35); D and I, immunostains for MHCIIb (clone BF-F3); E and J, IgG control. Scale bar represents 150 μm.