Pattern of change in the sprinting speed during sprint running

The puropose of this study was twofold: (a) to investigate the pattern of change in the sprinting speed that is the final results of the sprinting movements, and (b) to find out whether the characteristics in the sprinting speed change due to the differences in age, sex, sprinting ability and training status. One-hundred thirty male and 123 female ordinary students aged 6 to 18, and 30 male and 23 female sprint runners aged 9, 10, 11 and 18 participated in this study. They were instructed to excute an exhaustive sprinting. Sprinting times ranged from about 20 to 30 sec. The elapsed times were measured every five meters in their sprinting. In the analysis, the polynomial curve fitting from 5th-degree to 9th-degree was used for the predictions of the sprinting distances with respect to the elapsed times every 0.1 sec. From the relations of the distances to times the following speeds were computed: 1) the sprinting speed that was computed by differentiating the sprinting distance, and 2) the average speed form start to the elapsed time every 0.1 sec. The sprinting speed reached the peak speed after about 6to 7 sec from start. The average speed showed the peak speed after about 15 sec from start. These characteristics with respect to time remained unchanged despite the differences in age, sex, sprinting performance and training status. The time at the maximum average speed was particularly stable. The maximum average speed was about 90% of the maximum sprinting speed. This result also remained unchanged despite the differences in age, sex, sprinting performance and training status,respectively. These results indicate that the pattern of change in the sprinting speed with respect to time is rather constant without the distinction of age, sex, sprinting performance and training status. The sprinting performance, however, improved with age and by training. This result was mostly caused by the increase of the maximum sprinting speed with age and by training. These characteristics with respect to time and speed seem to cause the differences in the sprinting distance.