Study aim: To assess the anaerobic endurance of untrained male and female subjects by applying repeated maximal exercises. Material and methods: Untrained male subjects aged 23 - 27 years (n = 17, body height 170 - 197 cm, body mass 65 - 110 kg) and female ones aged 20 - 25 years (n = 10, body height 168 - 184 cm, body mass 55 - 86 kg) performed 6 maximal cycle ergometer (CE) exercises (64 flywheel revolutions each, spaced by 15 s intermissions, the load amounting to 75 g per kg body mass) and 6 bouts of 10 push-offs on an inclined plane device (IP). Mean and maximal relative power outputs were recorded, the ratio of the two - the performance index (PI), served as a measure of anaerobic performance. Results: Men attained significantly higher maximum power outputs than women in both tests but the respective PI values were in both genders alike. Highest power outputs amounted to 10.80 ± 0.91 and 9.45 ± 0.43 W/kg (cycle ergometer) for men and women, respectively, and to 20.06 ± 3.78 and 13.70 ± 1.88 W/kg (inclined plane) for men and women, respectively. No significant differences between genders were found for the PI values in either test but significant within-gender differences were detected between tests: mean PI values (±SD) amounted to 0.799 ± 0.052 and 0.850 ± 0.063 for men (p<0.01), and 0.803 ± 0.030 and 0.875 ± 0.078 for women (p<0.05), for CE and IP, respectively. Conclusions: The performance index enabled comparing male and female subjects, as well as different exercise tests consisting of repeated, short, maximal exercises, with respect to anaerobic endurance.