Ledecky's 800m gold medal hopes boosted as McIntosh opts out

Canadian wunderkind Summer McIntosh has opted out of the 800 metres freestyle at Olympic trials, boosting Katie Ledecky's chances of an unprecedented fourth gold medal in the event at the Paris Games.

McIntosh had raised hopes of a showdown for the 800m title in Paris when she became the first swimmer to beat the American great in 13 years in the event at a Florida meet in February.

However, the 17-year-old has not entered the 800m at next week's Canadian Olympic trials in Toronto.

The top two swimmers in each individual event qualify for the Games provided they have posted a time under the Olympic threshold.

McIntosh, a four-times world champion, will nonetheless swim an extensive programme at the trials, entered in the 100m, 200m and 400m freestyle, along with the 200m and 400m individual medley (IM), the 100m backstroke and the 200m butterfly.

She holds the 400m IM world record and is expected to be a major contender for the 200m IM at Paris, along with the 400m freestyle and 200m butterfly.

Seven-times Olympic champion Ledecky, the most decorated female swimmer in Games history, holds the 800m freestyle world record and the year's fastest time in the event heading into the United States' Olympic trials next month.

She is in line to bid for a fourth consecutive 800m gold medal at Paris and emulate Michael Phelps, the only swimmer to win an Olympic title four times in succession.