Cohort progression — Ujumisklubi Briis
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 breaststroke50 backstroke100 freestyle50 butterfly100 breaststroke100 backstroke200 freestyle200 medley200 breaststroke400 freestyle200 backstroke