Only Canada’s 16-year-old Summer McIntosh swam a world record in the women’s 400m breaststroke.

One of the sport’s biggest promises triumphed on Tuesday at the Canadian national team with a time of 3:56.08, thus improving the record of 3:56.40 minutes set by Australian Ariarn Titmus last May by more than three-tenths.

The Canadian teenager — who finished second behind American Katie Ledecky at the world championships in Donna Arena last year, and was undefeated in the 400-meter medley and 200-meter butterfly — has already broken several age-group world records, and for the first time among adults swam Best result ever.

McIntosh performed at an incredible pace, especially in the first half of the distance, after 200 meters he was more than a second faster than the partial time of the world record, with his time of 1:55.91 he would have won a bronze medal in the 200 last summer at Donna Arena.

(Featured image: Twitter/Devin Heroux)