vV̇O2max (velocity at maximal oxygen uptake), also known as maximal aerobic speed (MAS), is an intense running or swimming pace. This is the minimum speed for which the organism's maximal oxygen uptake (VO2 max) is reached, after a few minutes of constantly maintaining this exercise intensity. At higher paces, any additional increase in power is provided by anaerobic processes. In an incremental exercise test, it is the first speed at which any increase in exercise intensity fails to elicit an increase in oxygen consumption.
The vV̇O2max of world class middle- and long-distance runners may exceed 24 km/h or 2:30/km pace (15 mph or about 4:00/mile), making this speed slightly comparable to 3000 m race pace. For many athletes, vV̇O2max may be slightly slower than 1500 m or mile race pace.[citation needed]