A, superoxide production in gastrocnemius muscles from sham, tourniquet-induced ischemia-reperfusion, tempol + ischemia-reperfusion, and CoQ10 + ischemia-reperfusion groups, as assessed by dihydroethidium fluorescence. B, superoxide production in homogenates of gastrocnemius muscles from sham, tourniquet-induced ischemia-reperfusion, tempol + ischemia-reperfusion, and CoQ10 + ischemia-reperfusion groups, as measured by lucigenin chemiluminescence. MLU: mean light units. Data are mean ± S.E.M., n=7 mice in each group. *P<0.05 vs. sham; #P<0.05 vs. ischemia-reperfusion group.