Abstract : Maximal oxygen uptake (VO2 max) is regarded by some as the best single measurement of aerobic fitness. An other major determinant of successful endurance performance is the percentage of VO2 max that an athlete can maintain for a prolonged period. It is related to the lactate threshold. Two other factors also appear to be important for endurance activities as high economy of effort, or low VO2 value for the same rate of work; high percentage of ST muscle fibers. In the laboratory, the usual measurements of aerobic power include the determination of maximum oxygen consumption and the identification of lactate threshold. Testing aerobic power can help determine the type of aerobic training that should be emphasized.