Fig. 3. The relationship between normalized SDH and mATPase (A,C) and normalized mATPase and GPD (B,D) activity for type I motor unit fibers (glycogen depleted) and type I non-motor unit fibers (not glycogen depleted, located within the territory of the motor unit fibers) in a slow TA motor unit from a control (A,B) and a SI (C,D) cat is shown. In addition, data for all type I fibers across all cats are included for comparative purposes. Note that the ranges in the enzyme activities of motor unit fibers generally overlap those of non-motor unit fibers in both the control and SI cats. Abbreviations as in Figs 1 and 2.