Twenty-one women subjects were matched in terms of their Vo2max and assigned to one of two groups: (1) training at 30 s; or (2) 2 min with a 1:1 work: relief ratio (1:1 WR) before participating in a 7-week training programme which began at an intensity of 85% Vo2max and increased 5% every two weeks (90% and 95% Vo2max). The subjects trained to exhaustion four times per week. Maximal oxygen consumption (Vo2max), lactate threshold (Tlac) and ventilatory threshold (Tvent) were determined before and after the training programme. After training, there were significant increases (P < 0.05) in Vo2max (5% and 6%), Tlac (19.4% and 22.4%), and Tvent (19.5% and 18.5%). There were no significant group differences on any dependent measure but this research adds support to previous training studies in that a strong correlation (P < 0.05) between Tlac and Tvent is maintained from before to after the test. It was concluded that both formats of high intensity aerobic interval-training produce similar changes in Vo2max, Tlac and Tvent and that these changes appear to be independent of the length of the work interval.