抄録
This study aimed to investigate and assess the validity of a method to evaluate the change in the speed during straight and curve skating and the excess distance during skating the curved section in speed skating using only a digital video (DV) camera. In the 500 m races for men at national speed skating competitions, 27 skaters were captured by a DV at 60 frames/s, and by a local position measurement (LPM) system at 60 frames/s, which could automatically identify the skater’s trajectory. The change in the speed during each of the straight and curve skating measured by the DV was calculated from the number of frames between the adjacent landmarks on the track. The excess distance during skating the curved sections was calculated by the difference between the official lane distance and the real skating distance, which was estimated from the average speed in the second half of the straight section just before the curved section and that in the first half of the straight section just after the curved section. These parameters measured by the DV were compared with those measured by the LPM using the Bland-Altman analysis. Significant correlations were observed for the changes in the speed during skating through all the straight and curved sections between the DV and LPM. Additionally, significant correlations were also observed for the excess distance during skating the curved sections except for the first inner-lane curved section between the DV and LPM, and the correlation coefficient was particularly large for the second inner-lane curved section. These results indicate that it is possible to evaluate the changes in the speed during straight and curve skating and the excess distance during skating the curved sections, except for the high acceleration phase just after the start using only the DV.
