M -wave root-mean-square (RMS; A) and eccentric torque tracings (B) in wildtype (WT), mdx , and Sgcb ^−/− (β-sarcoglycan-deficient) mice subjected to an in vivo protocol (50 contractions with a 38° angle change at 2,000°/s). Eccentric torque was obtained from the anterior crural muscles (TA, EDL, extensor hallucis longus) while M-wave RMS was recorded from the TA. Data are mean ± SEM and adapted from Baumann et al. (2021).