Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean +/- SD 24 +/- 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: similar to 52% of (V)over dotO(2)peak: 500 kcal per session). Before and after the training intervention, all athletes performed an incremental specific (inline speed skating) and 1 nonspecific (cycling or running) step test according to the group affiliation. In addition to blood lactate concentration, oxygen uptake ((V)over dotO(2)), ventilatory equivalent (V-E/(V)over dot(2)), respiratory exchange ratio (RER), and heart rate were measured. The specific posttest revealed significantly increased absolute (V)over dot O(2)peak values (2.9 +/- 0.4, 3.4 +/- 0.7, p = 0.01) and submaximal (V)over dot O-2 values (p <= 0.01). VE/V(V) over dotO(2) and RER significantly decreased at maximal (46.6 +/- 6.6, 38.5 +/- 3.4, p = 0.005; 1.1 +/- 0.03, 1.0 +/- 0.04, p = 0.001) and submaximal intensities (p <= 0.04). None of the analysis revealed a significant group effect (p $ 0.15). The results indicate that both cycling vs. running exercise at similar to 52% of (V) over dotO(2)peak had a positive effect on the athletes' endurance performance. The increased submaximal (V)over dotO(2) values indicate a reduction in athletes' inline speed skating technique. Therefore, athletes would benefit from a focus on technique training in the subsequent period.