Fig. 4. The relationship between normalized SDH and mATPase (A,C) and normalized mATPase and GPD (B,D) activity for type IIa motor unit fibers (glycogen depleted) and type IIa non-motor unit fibers (not glycogen depleted, located within the territory of the motor unit fibers) in a fast TA motor unit from a control (A,B) and a SI (C,D) cat is shown. In addition, data for all type IIa 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.