The improbable has become somewhat routine for Canadian swimmer Summer McIntosh. 

She delivered yet another stellar performance at the Olympic & Paralympic Trials on Thursday night by trimming over a second off her world-record time in the 400-metre individual medley. 

"It sounds crazy but I think every time she dives in the pool we're expecting something spectacular because that's just the type of athlete she is," said teammate Kylie Masse. 

McIntosh led by a full second at the 50-metre mark and was at world-record pace midway through the race. She seemed to get stronger over the final 100 metres and finished in four minutes 24.38 seconds.

"I was really just focusing on having fun with the race and taking it 100 at a time because it's a pretty mentally challenging race," McIntosh said. "Overall I'm really happy. I've always had fun with it and I definitely did (tonight)."

Her previous world mark of 4:25.87 was also set at the Toronto Pan Am Sports Centre in April 2023.

It was McIntosh's third win of the Trials. She kicked off the event on Monday with a dominant showing in the 400 free, leaving the field well behind. 

The 17-year-old posted a comfortable win in the 200 free a night later, with second-place finisher Mary-Sophie Harvey noting it was "kind of nice" to be able to see her teammate's feet at the finish. 

McIntosh has been so far out in front in both prelims and finals this week that the only drama is between her and the clock. On this night, she conquered it.

The partisan crowd let out a roar when the hometown favourite was introduced and the noise only got louder through the race.

"It really keeps me going," McIntosh said. "If they weren't there I don't think I would have had the 4:25 world record in the first place, let alone this one tonight." 

McIntosh is the two-time defending world champion in the 400 IM. She'll appear in her second Olympics this summer in Paris.

She broke out as a 14-year-old at the Olympic Trials in 2021 and just missed the podium at the Tokyo Games that summer. 

"I hope people can just recognize and appreciate what they're seeing and appreciate her as an athlete and a person as well," Masse said. "She's incredibly kind and she works really hard.

"I'm really thrilled for her career so far and I know this is just the beginning."

The 400 IM includes butterfly, backstroke, breaststroke and freestyle. McIntosh said she has been making strides with the breaststroke - her weakest stroke "by far," she added - and the hard work is paying off.

"I really had a lot of confidence in my training because my breaststroke has been feeling good lately," she said. "So it's always good to see those little improvements coming to fruition."

Ella Jansen of Burlington, Ont., was over 14 seconds behind in second place in 4:38.88. She was three-10ths of a second off the Olympic qualifying time.

In other results, Toronto's Josh Liendo (47.55) and Calgary's Yuri Kisil (48.19) finished 1-2 in the men's 100 freestyle to secure spots in that discipline at the Games. 

Masse, from LaSalle, Ont., won the women's 200 backstroke in 2:06.24. Regan Rathwell (2:09.38) of Ashton, Ont., was also inside the Olympic qualifying time to lock up her spot for Paris.

Timothe Barbeau of Montreal won the men's 800 freestyle in 8:00.61 but did not qualify.

Two Canadian para-swimmers improved their national records in the women's 100 freestyle. Tess Routliffe of Caledon, Ont., won the S7 class with a time of 1:12.95 and Shelby Newkirk of Saskatoon finished in 1:13.68 in the S6 class.

Reid Maxwell of St. Albert, Alta., improved his S8 men's 100 freestyle national mark with a time of 1:00.23.

Competition continues through Sunday.

This report by The Canadian Press was first published May 16, 2024.