Ski mountaineering (skimo) has recently gained popularity and established itself as a competition sport. It requires a specific training with a high hypoxic load. Although a variety of sport specific performance test protocols have been developed, a specific method for ski mountaineering (skimo) is pending. After the development of a sport specific ergometric protocol with recreational athletes in pre-tests a standard sport specific protocol was defined, concerning treadmill speed, slope and step test variables. This protocol was evaluated for its effectivity with members of the German national skimo team (6 male, 2 female). All athletes performed two spiroergometry test protocols, a standard bike test profile followed by sport specific spiroergometry. This skimo-specific test involved an incremental step test with skis on a treadmill, using a standard incline of 20° with an stepwise speed increase. Spiroergometry and blood lactate (BL) data were recorded and the first and second ventilatory thresholds (VT1 and VT2) were determined. All athletes could complete the test without any technical problems and reached cardiopulmonary exhaustion. The mean test break off BL was 9.98 ± 2.0 mmol/L for the bike test, and 9.28 ± 2.3 mmol/L for the skimo test. The heart rate at VT1 as a percentage of the maximum heart rate did not differ significantly between protocols. Heart rates at VT2 did not significantly differ between both protocols, but varied in both directions. In three athletes, VO2max was higher in the skimo tests than in the bike tests, while the remaining five athletes exhibited the opposite situation. VO2max did not differ significantly between skimo and bike tests (p = 0.35), but it varied in both directions. Motion analysis revealed motoric deficits in two cases. The study indicates that skimo and bike tests are not fully comparable. The skimo and bike test results vary with respect to the majority of test parameters and statistical findings, nevertheless these findings were not statistically significant. These differences were furthermore found to be inconsistent, which is the most valuable finding of the study. It can thus be concluded that a sport specific test is important for both optimal exercise testing and the development of training recommendations for skimo athletes.