TFAM and Mitochondrial myopathy: Our results show clear-cut signs of impaired intracellular energy metabolism before, during and after the fatiguing stimulation bout in Tfam KO muscles at 11 and 14 weeks of age, which is consistent with the impaired mitochondrial oxidative metabolism observed in mitochondrial myopathy patients (Arnold et al., 1985; Hayes et al., 1985; Matthews et al., 1991; Moller et al., 2005; Taylor et al., 1994).