Loss of dystrophin and utrophin in dystrophic muscles impairs transcriptional remodeling of oxidative phosphorylation with low-frequency stimulation (LFS). (A) Expression of genes involved in oxidative phosphorylation and mitochondrial ribosomes assessed by RNA sequencing in extensor digitorum longus (EDL) muscles (n = 3/group) increased by LFS in red, decreased by LFS in blue. (B) Complex I-supported leak respiration (CIL; pyruvate + malate) in permeabilized EDL fibers assessed by high-resolution respirometry (n = 3–10/group). (C) Complex I-supported coupled respiration (CIP) in permeabilized EDL fibers assessed by high-resolution respirometry (n = 3–10/group). (D) Complex II-supported coupled respiration (CI + IIP) in permeabilized EDL fibers assessed by high-resolution respirometry (n = 3–10/group). (E–G) Complex I-supported respiration (CIP; pyruvate + malate + ADP) at varying [ADP] (100–8,000 μM) in permeabilized EDL fibers of BL/10 (E), mdx (F), and dko (G) mice assessed by high-resolution respirometry (n = 3–10/group). Data are means ± SEM. Two-way ANOVA followed by Tukey's multiple comparison test (B–D); Paired Student's t-test (E–G); ME: main effect; #p < 0.10, ∗p < 0.05, ∗∗p < 0.01, ∗∗∗∗p < 0.0001.