Comparison of swimming velocity and stroke rate and length in the 50-m front crawl by age in Japanese competitive swimmers

The purpose of this study was to investigate the effects of age on the swimming velocity, stroke rate and stroke length of male and female competitive swimmers in the 50-m front crawl. The swimmers examined were top-level Japanese competitive swimmers in the 50-m freestyle event at national level swimming competitions held in Japan in 2018 (50-m pool). The swimmers were divided into 5 age groups (G-U10: under 10 age group, G11-12: 11-12 age group, G13-15: 13-15 age group, G16-18: 16-18 age group, G-O19: over 19 age group). The average velocity (SV), average stroke rate (SR) and average stroke length (SL) from 15 m to 45 m in the 50-m freestyle event were analyzed and compared between the age groups by gender. SV significantly increased with age in both males and females. SR in males increased significantly with age, whereas that in females did not differ significantly between groups. SL in females increased significantly with age, whereas that in males did not increase significantly after G11-12. The increase of SV in females with age was due to the increase in SL after age 13. On the other hand, the increase of SV in males with age was due to the increase in SL until age 12 and in SR after age 13. These results suggest that increasing the SL with age may improve the SV in females, and that increasing the SL and SR with age may improve the SV in males.