Submaximal and maximal forces from 12-month-old WT (n = 18) and Neb-cKO mice (n = 17). A, Representative force traces of the plantar flexor muscles recorded during a 150-Hz tetanic stimulation. B, Plantar flexor muscles specific maximal force. C,D Plantar flexor muscles force recorded during a 20-HZ stimulation (C) and a 40-Hz stimulation (D). Results in C and D are expressed relative to the maximal tetanic force (measured at 150 Hz). Values are mean ± SEM. ***P < 0.001, significantly different from WT mice. Neb-cKO, conditional nebulin knockout; WT, wildtype