World Aquatics Championships in the context of Long course

An Olympic-size swimming pool is a swimming pool which conforms to the regulations for length, breadth, and depth made by World Aquatics (formerly FINA) for swimming at the Summer Olympics and the swimming events at the World Aquatics Championships. Different size regulations apply for other pool-based events, such as diving, synchronized swimming, and water polo. Less onerous breadth and depth regulations exist for lesser swimming competitions, but any "long course" event requires a course length of 50 metres (164 ft 0.5 in), as distinct from "short course" which applies to competitions in pools that are 25 metres (82 ft 0 in) in length (or 75 feet (22.9 m) in the United States). If touch pads are used in competition, then the distance is relative to the touch pads at either end of the course, so that the pool itself is generally oversized to allow for the width of the pads.

An Olympic-size swimming pool is used as a colloquial unit of volume, to make approximate comparisons to similarly sized objects or volumes. It is not a specific definition, as there is no maximum limit on the depth of an Olympic pool. The value has an order of magnitude of 1 megaliter (ML). Some style guides caution against the hyperbole of describing any relatively large pool as "Olympic-size[d]".

Kathleen Genevieve Ledecky (/ləˈdɛki/ lə-DEK-ee; born March 17, 1997) is an American competitive swimmer. She is the most decorated female swimmer in history and the most decorated American woman in Olympic history, with a total of 14 Olympic medals, including nine golds. She shares the record for the most Olympic gold medals won by a woman with Larisa Latynina and ranks as the fifth-most decorated Olympian of all time. She is regarded as the greatest female swimmer of all time.

Ledecky has won a record 18 individual gold medals at the World Aquatics Championships, and is the world record holder in the women's 800- and 1500-meter freestyle long course and 1500-meter freestyle short course, as well as the former world record holder in the women's 400-meter freestyle (long course) and 800-meter freestyle (short course). In her international debut at the 2012 London Olympic Games as a 15-year-old, Ledecky unexpectedly won the gold medal in the women's 800-metre freestyle. Four years later, she left Rio de Janeiro as the most decorated female athlete of the 2016 Olympic Games, with four gold medals, one silver medal, and two world records.