INTRODUCTION: Technique detection in both classical and skating in cross-country skiing is an essential issue in improving competitive performance (Takeda et al., 2019). In this study, we tried to detect skating sub-techniques, V1, V2, V2a, and others (turning or gliding) using a kinematic global navigation satellite system (GNSS). METHODS: Participants were one former male Olympic athlete skier aged 41 yrs and two former competitive female XC skiers aged 41 yrs and 24 yrs from Japan. Each participant performed 2-time trials of 3 km with the skating technique with 1-hour rest between trials. One time trial with a slower gliding speed ski and one with a faster gliding ski controlled by different kinds of ski waxing and in randomized order across participants. Air temperature was -1°C. A triple-band helical GNSS antenna was attached to the top of the skier`s head, and the kinematic positioning data was measured by a data logger with a sampling rate of 10 Hz (the measurement accuracy is 1 to 2 cm (Miyamoto et al., 2017)). A video camera (GoPro Hero 9 Black) was attached to the chest of the participant to focus on skiing movement to detect the technique used during skiing. Both vertical and lateral head movements were visually extracted from the GNSS position data to determine the characteristics of each sub-technique. The number of each sub-technique counted by GNSS was compared with video-counted data in both faster and slower gliding skis, respectively. RESULTS: The match ratio of the used all-technique counts between video and GNSS data for a total of six trials was 99.5 ± 0.4%. Match ratios of V1 (101.2 ± 1.5%), V2 (98.5 ± 4.0%), V2a (109.4 ± 16.7%), and others (94.9 ± 19.0%) were observed. When participants used a faster gliding ski, the used technique ratio for V1 was almost unaltered, V2 decreased (-41 to -5%), V2a increased (6 to 21%), and others increased (-10 to 59%) compared to slower gliding ski. DISCUSSION/CONCLUSION: Both vertical and lateral head movement analysis using GNSS position data can detect all sub-techniques in skating. Changing ski gliding speed altered the use of the skating sub-technique ratio.
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