LACK OF ANTIOXIDANT ADAPTATION TO SHORT-TERM AEROBIC TRAINING IN HUMAN MUSCLE

The effects of 8 wk of 35 min of aerobic cycle training (3 times/wk) o n indexes of male and female human vastus lateralis muscle antioxidant status were investigated. Training resulted in significant elevations in whole body maximal O-2 consumption and muscle citrate synthase act ivity. Despite this, muscle superoxide dismutase, catalase, and glutat hione peroxidase activities were not significantly altered by the trai ning protocol. In addition, training did not-affect muscle vitamin E ( alpha- and gamma-tocopherol) concentrations. Glutathione status determ ined as the concentrations of reduced glutathione (GSH), oxidized glut athione (GSSG), total glutathione (GSH + 2 x GSSG), and GSH/GSSG ratio was unaffected by the training protocol. There were no significant di fferences between males and females in any indexes of muscle antioxida nt status. These results indicate that the moderate aerobic training t ypically performed by regularly exercising humans did not positively a lter endogenous antioxidant status. This suggests that short-term aero bic training increases capacity for flux through the citric acid cycle without necessarily increasing the ability to handle potential free r adicals generated by the enhanced electron flux.