Pool swimming is a race against the clock: the winner is whoever covers the distance legally in the shortest time. The strokes are freestyle, backstroke, breaststroke and butterfly; a medley race uses all four in a set order.
International long-course races are held in a 50-metre pool, short-course races in a 25-metre pool. Swimmers start from the blocks; backstroke starts in the water.
An approved racing suit, goggles and a cap; the starting blocks and the electronic timing are part of the facility.
A race lasts from about 21 seconds over 50 metres to roughly 15 minutes over 1500 metres.
Over the same distance a short-course race has more turns and more underwater phases. That is why World Aquatics keeps the two pool lengths as separate record lists.
| League | Teams | People |
|---|---|---|
| Swimming – World Records Men | – | 30 |
| Swimming – World Records Women | – | 16 |