Aims: To assess the agreement between the Ross treadmill method and the Åstrand ergometer cycle method, and the repeatability of each method.

Methodology: Twenty healthy people aged 22.5 ± 2.2 years were tested on two different days, each day with both methods with a pause of 30 min between the tests. The tests were executed in the reverse order the following test day.

Major findings: There was no statistical difference between the methods. The correlation (R) between the methods was 0.85. The mean difference (95% CI) of the methods was 0.050 (0.046–0.054) L/min and the limit of the agreement (mean difference ±2SD) was 0.81 L/min. No significant differences in test-retest were shown for either test. The mean difference for Åstrand tests was 0.12 L/min and 0.08 L/min for the Ross tests. The coefficient of repeatability was 0.88 L/min (23%) for the Åstrand test, and 0.78 L/min (20%) for the Ross test.

Conclusion: The Ross treadmill test could be used as an alternative to the Åstrand cycle ergometer test, showing good agreement and repeatability. The large variation should be considered when estimating aerobic capacity on an individual level, although either method could be used for group studies where maximal measurements are not possible.