LONDON, June 30 (Reuters) - Tokyo will be the first Summer Games in a quarter of a century without Michael Phelps, the greatest of Olympic medal machines, but even if the giant has gone U.S. swimmers are still set to rule the pool.
Phelps owns a record 28 Olympic medals, including 23 golds, eight of which he captured in Beijing in 2008. He retired in 2016 after taking a final five golds from Rio de Janeiro -- his fifth Olympics.
Compatriot Katie Ledecky, the distance dominator of women's freestyle, and men's sprint ace Caeleb Dressel have shown already they are more than capable of Phelps-like single Games golden hauls.
Ledecky was the most successful female athlete in Rio with four golds and a silver, adding to the 800m freestyle gold she won as a 15-year-old at London 2012, and the expectations are high.
Three more golds in Tokyo would lift the 24-year-old Stanford University psychology graduate alongside retired compatriot Jenny Thompson as the most successful female Olympic swimmer.
Five golds, entirely possible from four individual events and a relay, would take Ledecky's tally to 10 -- a record for a female athlete from any sport. Only Phelps has won more than that.
Ledecky holds the world records for 400, 800 and 1,500 metres freestyle and the addition of the latter event to the women's programme, bringing parity with the men, is a big boost for her.
She faces the prospect, however, of defending her 200m freestyle title on the same morning session as the 1,500 final.
Another 800m gold would meanwhile be her third in a row in the distance. Only three swimmers, one of them Phelps, have ever pulled off such a hat-trick.
On the men's side, Dressel won two relay golds in Rio but his eight medals at the 2019 world championships sent hopes soaring and he remains the favourite in the 50 and 100m freestyle as well as 100m butterfly.
There will be strong challengers to both Americans at a Games where the COVID-19 pandemic has disrupted training for many.
Australian Ariarne Titmus caused a sensation at the 2019 world championships when she beat an unwell Ledecky to the 400m gold, but the Tasmanian is still regaining strength after a three-month layoff for a shoulder injury.
Sweden's 100m butterfly champion Sarah Sjostrom is also battling back from a broken elbow she suffered falling on ice in February.
Katinka Hosszu won three golds in Rio and is a good bet to defend her 400 individual medley title but male compatriot Kristof Milak is Hungary's rising star after taking Phelps' 10-year 200m butterfly world record.
Britain's reigning champion and world record holder Adam Peaty looks unbeatable in the 100m breaststroke.
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