Cohort progression — Bureå Simsällskap
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 freestyle100 freestyle50 breaststroke50 backstroke50 butterfly100 medley100 breaststroke100 backstroke25 freestyle25 breaststroke25 backstroke25 butterfly200 freestyle100 butterfly