The traditional view of VO2max owes a great deal to the work of A. V. Hill, who conducted experiments on exercising man in Manchester, England, in the 1920's. Hill and colleagues proposed that there is an upper limit to oxygen uptake (VO2max), that there are inter-individual differences in this variable, and that VO2max is limited by the circulatory and/or respiratory systems. They demonstrated that oxygen uptake increases linearly with running speed, but in some subjects it eventually ''reaches a maximum beyond which no effort can drive it,'' a phenomenon now referred to as the VO2 plateau. In recent years, Timothy Noakes has strongly criticized Hill's concept of VO2max. He maintains that the absence of a VO2 plateau in some subjects is proof that oxygen delivery is not a limiting factor for VO2max. This view fails to recognize that the plateau is not the principal evidence for a cardiorespiratory limitation. Noakes rejects the VO2max paradigm of A.V. Hill in its entirety. The alternative paradigm he proposes is that endurance performance is limited by ''muscle factors.'' Noakes suggests that the best distance runners have muscle characteristics that allow them to achieve higher running speeds, and since running speed is linearly related to oxygen uptake, an indirect consequence of this is that they will have higher VO2max values. This is exactly the opposite of how the relationship between VO2max and running speed at the end of a maximal exercise test should be viewed. Noakes offers little evidence to support his views, and they conflict with a vast body of scientific evidence showing that oxygen transport is a major determinant of endurance performance. After carefully reviewing the evidence on both sides of the issue, we conclude that the older ''classical'' VO2max paradigm of A.V. Hill is the correct one.
