To quantify the junior-to-senior successful transition rate in sprint swimming events in elite European performers.

Retrospective analysis of publicly available competition data collected between 2004 and 2019.

The yearly performance of 6631 European swimmers (females = 41.8% of the sample) competing in 50 and 100 m freestyle, backstroke, breaststroke, and butterfly were included in the analysis. The junior-to-senior transition rate was determined as the number of elite junior athletes who maintained their elite status in adulthood. To investigate how the definition of elite may affect the calculation of the transition rate, we operationally defined elite athletes as those ranked in the all-time top 10, 25, 50, and 100 in their category. We also calculated the correlation between junior and senior performances.

The average transition rates ranged, depending on the age of reference, from 10 to 26% in males and from 23 to 33% in females. The transition rate for the top 100 junior swimmers was greater than that for the top 10 swimmers. In general, swimmers who swam 50 m showed a slightly lower transition rate compared with those that swam 100 m. Depending on the age of reference, low-to-moderate correlations were observed between junior and senior peak performances.

Most elite junior athletes did not maintain the elite level in adulthood. Except for athletes in the last year of the junior category (18 years for males and 17 years for females), junior performances were poorly correlated with senior performances.