New Method For Researching Pacing Strategy In Cross-country Skiing Based On Fine-grained Analysis Of Gnss Data

PURPOSE: To examine the pacing strategies of China's elite cross-country skiers in sprint events, across different terrain sections. METHODS: Sixteen male skiers from the national cross-country skiing team completed two tests: (1) a maximum speed test and (2) a 1.5 km sprint skating race on snow. The 1.5 km course consisted of six sections (S1-S6), and GNSS and timing equipment recorded the skiers' time, speed, and free technique selection during the race. Statistical parametric mapping normalized the skiers' skating position and speed. A SPM 1D regression model analyzed the relationship between instantaneous speed, and section time. RESULTS: (1) Instantaneous velocity in different sections correlated significantly with section time (p < 0.01). In particular, the uphill sections S3 (339-476m), S3 peak (517-537 m), and S5 (1127-1167m), the flat sections S1 (13-84m) and S6 (1223-1400m), and the downhill section S2 (85-134m), S4 start (652-730 m), and turning area influenced section time. Moreover, average skiing speed in the uphill section S5 was significantly higher than in S3 (p < 0.01). (2) The total number of cycle movements and the number of G3 techniques correlated negatively with race time and time spent on the uphill terrain (r > 0.65, p < 0.01). Faster skiers had 3.6% and 3.8% higher G3 speed and cycle rate, respectively, on uphill and flat sections than slower skiers (p < 0.01). Also, average skiing speed and cycle rate increased by 45% and 2.5%, respectively, on the transition sections S1-S2 and S3-S4 (p < 0.01). CONCLUSIONS: (1) Pacing strategies on different sections of the sprint course affect athletes' performance. Athletes adopt a more positive pacing strategy on uphill sections and near the finish area. Faster athletes have higher instantaneous speeds on flat sections during the fast start and in the finish area, which relate significantly to section time. Also, athletes who have faster velocity on downhill sections during the turns tend to have better race time. (2) A lower number of cycle movements and a higher percentage of G3 technique relate to better performance in the sprint event. Faster athletes on uphill and flat sections have longer cycle lengths for G3 speed. Moreover, maintaining a higher cycle rate on the transitions at the top of uphill sections helps to sustain higher skiing speeds.