The basics
The Medley Relay races are a combination of all four strokes. Each stroke is swum by a different swimmer, who completes two lengths of the pool. The race starts with Backstroke (as they must be in the water to start), followed by Breaststroke, then Butterfly, finishing with Freestyle. The next swimmer may not leave the starting blocks until the previous swimmer has touched the finishing pad.
A team’s changeovers can make the difference between winning and losing as athletes who go too late lose valuable time, but going too early risks disqualification.
Competition format
The competition starts with heats. Teams are seeded, and these seedings are used to determine the heat a team swims in and the lane they are allocated. The top eight teams then progress straight to the final.
Find out more about the men's and women's Medley Relay competitions at the Olympic Games on the International Olympic Committee website.
