Abstract
CrossFit is one of the sports disciplines where endurance play a significant role in the performance. For testing anaerobic fitness it is important to choose the means that are part of the exercise and have a good transfer to the sport. A sample of competitive crossfitters (n = 12) underwent stress tests on the assault air bike (AB) (60 s) and Wingate. In addition to the performance parameters (Wmax, Wmean, W/kg, cal), lactate values after exercise (1st, 5th, 10th and 15th minute) were monitored. The results showed significant differences in both the absolute values of lactate and the development of the lactate curve (α = 0.05). The correlation of the selected variables showed a significant relationship between the average Watts value and the calories traveled (0.894). Testing anaerobic fitness with AB appears to be a suitable variant for CrossFit, as well as monitoring the development of lactate curve. Due to the original design of the study, it is necessary to verify the results.