Next, we used the permeabilized fiber protocol and treatment with either catalase or AACOCF3 to identify and compare the relative composition of hydroperoxide production rates in several models of neurogenic atrophy including an aging time-course, accelerated sarcopenia with neuromuscular degeneration (Sod1−/− mice), and end-stage ALS motor neuron disease (SOD1G93A mice). The gene discussed is CAT; the disease is motor neuron disorder.