OBJECTIVE The purpose of this study was to compare values of maximal accumulated oxygen deficit (MAOD; a measure of anaerobic capacity) and peak post-exercise blood lactate concentration ([lactate]; a reflection of glycolytic contribution) in running and cycling, in women and men. METHODS One hundred and nineteen women and 104 men performed an exhaustive treadmill test of ~5 min duration; 106 women and 110 men performed an exhaustive cycle ergometer test of ~5 min duration. Oxygen demands for the exhaustive exercise tests were estimated by extrapolation from steady state VO2 values. For running, an upwardly curvilinear relationship between demand and speed (i.e., with demand a function of speed1.05) was used. For cycling, a linear relationship between demand and work rate was used. RESULTS The MAOD was 22% higher (P<0.01) in running than in cycling, and 32% higher (P<0.01) in men than in women. Peak [lactate] was 8% higher (P<0.01) in running, and 23% higher (P<0.01) in men. The VO2max was 10% higher (P<0.01) in running, and 14% higher (P<0.01) in men. CONCLUSIONS These results indicate that some of the differences between running and cycling, which affect MAOD, do not similarly affect VO2max or peak [lactate]. It is possible that greater lactate removal by the upper body musculature during running permits the greater anaerobic capacity in running, and explains the relatively small difference in blood [lactate] in running compared to cycling.