Author(s): YUDA, J., YOKOZAWA, T.2, KIMURA, Y.2, KUMAGAWA, D.3, Institution: JAPAN WOMEN'S COLLEGE OF PHYSICAL EDUCATION, Country: JAPAN, Abstract-ID: 590

INTRODUCTION:
The skater must exert push-off power to the right direction with tilting to the inside of the ice rink to counteract the centrifugal force during the curve phase. Therefore, obtaining a high skating velocity during this phase poses a significant challenge for novice speed skaters during their developmental period. This study identified the characteristics of stroke parameters that influence performance during the curve phase in a 500-m speed skating race among elementary school children.
METHODS:
A total of 93 elementary school children (56 boys and 37 girls) participated in a 500-m speed skating time trial using a single track (inner lane). They were recorded using three synchronized high-speed video cameras (300 fps) positioned at the middle of the second curve (~350 m from the start line). The recorded images were analyzed using a panning direct linear transformation technique. The three-dimensional coordinates of the segment endpoints and blades were determined to calculate the stroke parameters during the skating cycle. One skating cycle was subdivided into right and left strokes based on the instant when the blade left the ice. The average horizontal velocity of the skater’s center of mass during one cycle (CM velocity) was obtained by differentiating the displacement. The cycle and, left and right stroke frequencies were calculated as the reciprocal of the time for one cycle and each stroke, respectively.
RESULTS:
The height, weight, age, and 500-m race time for boys (mean ± SD) were 1.44 ± 0.10 m, 39.2 ± 9.0 kg, 10.8 ± 1.0 y, and 52.10 ± 4.21 s, respectively. Girls had corresponding values of 1.44 ± 0.09 m, 39.9 ± 9.2 kg, 10.7 ± 1.0 y, and 53.29 ± 5.19 s. Significant negative relationships were found between 500-m race time and anthropometric parameters (height and weight) for boys (r= −0.696 and r= −0.503, p<0.001, respectively). In contrast, no significant relationship as well as boys observed in girls. Regarding performance during the curve phase, the importance of higher skating velocity during this phase was highlighted by strong significant negative relationships between 500-m race time and CM velocity for boys and girls (r= −0.985, r= −0.986, p<0.001, respectively). In boys, concerning the relationship between CM velocity (10.40 ± 0.95 m/s) and temporal parameters (cycle frequency: 1.05 ± 0.08 cycle/s, left stroke frequency: 2.36 ± 0.21 stroke/s, right stroke frequency: 1.92 ± 0.17 stroke/s), a positive relationship was observed only with the right stroke frequency (r= 0.375, p<0.01).
CONCLUSION:
These results indicate that the performance of boys in the 500-m race improved with growth. In boys, achieving higher velocity in skating requires skaters to enhance their external power output, defined as the product of work per stroke and stroke frequency. The performance development in boys was primarily attributed to an increase in work per stroke during the left stroke with growth.