The repeated crack of the starter pistol punctuates the quiet morning. Training at the University of Southern California, sprinter Andre De Grasse readies in the starting blocks. At the sound of the gun, he springs forth and flies 20 or so metres down the track before slowing and turning around to do it again.
It’s a warm Friday in mid-June. Mr. De Grasse smiles and jokes with his USC track teammates during a light practice. He has broad shoulders and a thin waist. He’s 5-foot-10 and 155 pounds. There is zero outward indication that Mr. De Grasse, one week earlier, had run two of the fastest races in history.