Due to the recent introduction of sprint races and an increasing number of mass start competitions in the World Cup series, new aspects of training and testing are becoming fields of research. This could be attributed to the upcoming specialization of athletes in sprint racing, as well as to the technical modifications demonstrated for selected techniques, eg. double poling (Holmberg et al. 2005) and doublepush skating (Stöggl et al. 2008a). Both technical modifications were found to be superior to the conventional skiing style. In addition, the mean skiing velocity in WC sprint races has shown a steady increase in skiing speed (Stöggl et al. 2008b), reaching mean race speeds of up to 9.5m/s in classical style and up to 10m/s in skating. It should be noted that skiing speeds in the majority of scientific studies are quite apart to these values. It was demonstrated that there is a moderate to high correlation between sprint performance and performance in distance races (Stöggl et al. 2008b). It was recently shown that short duration maximal skiing speed and specific maximal and explosive strength are good predictors of cross-country skiing sprint performance (Stöggl et al. 2007a,b 2009). Interestingly it was found that skiers with higher maximal power output and maximal skiing speeds showed, in addition to their higher performance, less fatigue during all-out tests of the same duration as a sprint race. These results may be coupled to the prerequisites of modern sprint techniques, as characterized by high peak forces and high force impulses over a short time. The combination of high force output over a short time and thus a longer recovery time was found to be faster and more economical (Holmberg et al. 2005; Stöggl & Müller 2009). Furthermore, it was found that cycle length but not cycle rate was related to performance, especially at submaximal velocities. This was particularly true of the V2 technique and diagonal stride, whereas in double-poling there seems to be an optimum cycle length and cycle rate pattern (Stöggl & Müller 2009). Measures of aerobic capacity (VO2max) showed only low correlations to sprint performance. However, it should be noted that a high level of VO2max should be the basis but also that other factors that are mainly associated with neuromuscular factors and anaerobic capacity discriminate between weak and strong sprint skiers. These findings should lead to a reconsideration of concepts in the training and testing of cross-country skiers. In addition to common VO2max and incremental step tests, also strength and speed tests should be included. Maximal and explosive strength training sessions could also be useful additions to conventional aerobic and strength endurance training.