Objective of the study was to analyze the competitive performance of the world skiathlon leaders in the 2021 World Ski Cup. Methods and structure of the study. Subject to the study was the 30km skiathlon event of the World Nordic Ski Cup in Obersdorf (Germany) in January 2020. We shot the competitive performance videos on a 10° ascent in a key point of the eight loops by a video cam fixed on a tripod perpendicular to the track. The video captures were processed and analyzed using the DartfishPro 9 software toolkit to obtain the individual ascension speed, stride length, frequency and kick-off time for the 25 world strongest skiathletes. We also analyzed the individual time/ speed in every track section versus the terrain conditions, with the speed profiles verified by the formal competitive reports and analyses, including the detailed event statistics. Results and conclusion. The middle-distance (2.3km) video captures yielded the ski stride macro-kinematics variation data including stride length, frequency and speed on ascend for each of the 25 competitors. The speed-ups in the final loops were associated with growth of the stride length plus insignificant growth of the movement frequency. The stride length was found correlated with the speed in agreement with the study data by Stögg l.T., Pellegrini B. and Holmberg H.C. (2018) [7], although we would emphasize importance of the kick-off power growth in the final spurt. This aspect should be taken into consideration by the training systems designers since growth in the stride length is secured by the kick-off power that require high muscular endurance. Of special interest was the macro-kinematics analysis of the race leaders versus outsiders. The skiathlon leaders` racing tactics profiled by the macro-kinematics analysis provides an insight into the individual speed control patterns. We found the speed significantly falling on ascends in the skating-stride loops five and six and growing in the final loop. The race outsiders ranked 11-20th on the event scoreboard were tested with the lower speed variations, although their speed and stride length in loop six were tested higher than the leaders` ones. The ascension speed was tested to grow in both the leaders and outsiders groups. We found the individual speed and kick-off power acceleration resource mobilized in the final loops being critical for success in the race. We recommend the study data and findings for application in the precompetitive training systems by the potential qualifiers for the 2021 World Ski Cup.
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