World record progression 4 × 50 metres medley relay

This article includes the world record progression for the 4×50 metres medley relay and it shows the chronological history of world record times in that competitive short course swimming event. The 4×50 metres medley relay is a medley race in which each of four swimmers on a team swims a 50-metre leg of the relay, each swimming a different stroke, in the following sequence: Backstroke (this can only be the first stroke, due to the necessity of starting this leg in the pool rather than by diving in); Breaststroke; Butterfly; and Freestyle ("freestyle" means any stroke other than backstroke, breaststroke or butterfly – most swimmers use the front crawl).

Source: Wikipedia — World record progression 4 × 50 metres medley relay (CC BY-SA 4.0)