Cohort progression — UKS Butterfly
Median season-best times of each birth-year cohort, overlaid by age — shows how consecutive groups developed at the same stage of training.
Event: 50 freestyle50 backstroke50 butterfly50 breaststroke100 freestyle100 backstroke100 medley200 freestyle
50 m freestyle men · 25 m pool
X: swimmer age in season · Y: median season-best time
born 2009