This study aimed to: (i) present normative data of the variables related to the start in
the four swim strokes by tier and sex, and; (ii) understand the relationship between the 15th
meter mark time and the final race time of the male and female swimmers competing in the four
50 m events at the 2021 European Championships. Participants were all male and female
swimmers who competed in the 50 m events at the 2021 LEN European Championships held in
Budapest. The official race times and block times were retrieved from the official competition
website. All starting variables were analyzed in a dedicated software for race analysis. The 15th
meter mark time was used as the start main outcome. For all events by sex, the 15th meter mark
time was the variable presenting the highest and largest tier effect (p < 0.001) besides the final
race time. Overall, despite the swim stroke, the variables related to the underwater phase were
also responsible for the significant tier effect (p < 0.001). The 15th meter mark time presented a
high to very-high relationship with the final race time in all four swim strokes. This relationship
was stronger in freestyle (both sexes). That is, swimmers who achieve the 15th meter mark sooner
are more likely to deliver better performances. Coaches must be aware that the underwater
phase plays a key-role on the swimmers’ (both sexes) start performance. Nonetheless, different
strategies can be used based on the swimmers’ strength and weaknesses. Moreover, the start
performance in all four swim strokes and in both sexes can strongly predict the final race time.
