This involves finning up and down a swimming pool (or in the sea), to cover a horizontal distance. Physically, it is very demanding. This can either be done in a 25m pool or in a 50m pool. Using a 50m pool is better for this category since fewer turns are necessary which tend to break the rhythm.
In short: swimming as far as possible underwater
|UK Men||226||Dave King|
|UK Women||200||Alice Hickson|
|World Men||300||Mateusz Malina (Poland)|
|World Women||243||Magdalena Solich-Talanda (Poland)|