Many coaches use field tests to estimate athlete's aerobic capacity. Recently it has been has suggested that the 5 minute run an accurate estimator of aerobic capacity as is the 15 minute aerobic run. The aim of this experiment was to determine whether the 5 minute run was as accurate an indicator of aerobic capacity as the 15 minute run. Also we wished to determine some correlational values between measured VO2max and both the 15 minute and 5 minute runs as well as determining some regression equations to calculate VO2max (mls.kg-1.min-1) given the distance run in the 5 or 15 minute runs. We found that the 15 minute run was still the best indicator of aerobic capacity for all age groups (r = 0.881, 851, 671 and 881 for 12, 13, 14, and 15 years respectively). The 5 minute run correlated significantly with the 15 minute run and with VO2max, in all cases. Correlational values were all moderate to high in nature with no correlation being lower than r = 0.534. We would conclude that the best method to estimate aerobic capacity in a field situation is to use the 15 minute run.