Serial sections of the PM muscle stained for immunohistochemistry, enzyme histochemistry and histology. A-D: Sections were stained with a battery of MAbs against specific MyHC isoforms: BAF8 anti MyHC I (A), SC71 anti MyHC IIA and IIX (B), BF35 anti MyHC I and IIA (C), and S58H2 anti MyHC I and IIX (D). E-F: Sections assayed for mATPase activity after acid (pH 4.42, E) and alkaline (pH 10.35, F) preincubations. G-I: Sections assayed for SDH (G), GPDH (H), and PAS for selective staining of glycogen (I). J-K: Histological staining with PAS after digestion with α-amylase to reveal capillaries (J) and haematoxylin-eosin to show total nuclei (K).