and 19 we described the importance of the anaerobic sources of ATP in maximal perfor- mances lasting two minutes or less. If this informa- tion is correct, and we think it is, then the short-term anaerobic races shouldn't be affected by the low PO at altitude because O2 transport to the muscles is not limiting performance. Table 24.1 shows this to be the case when the sprint performances of the 1968 Mexico City Olympic Games 2300 m) were com- pared to those in the 1964 Tokyo Olympic Games (sea leve) 65). The performances improved in all but one case, in which the time for the 400-meter run for the women was the same. The reasons for the improvements in performance include the "normal" gains made over time from one Olympic Games to the next and the fact that the density of the air at altitude offers less resistance to movements at high speeds.