Josh Kerr’s Last Hard Workout Was the Fastest 1,200m in History. The Mile World Record Attempt Comes Saturday

Josh Kerr covered 1,200m in 2:42.45 in his final hard session before Saturday’s mile world record attempt in London, a time faster than anyone has ever been clocked for the distance. Kerr released video of the time trial on his YouTube channel Friday, barely a day before he lines up at London Stadium.

Hicham El Guerrouj ran 3:43.13 at Rome’s Olympic Stadium in July 1999, and only one man, Jakob Ingebrigtsen, has come within a second of it since. Breaking it demands an average of 55.45 seconds per 400m lap. Kerr announced his attempt, branded Project 222, in March and has pointed his entire season at Saturday’s Emsley Carr Mile at the London Diamond League.

The trial capped Kerr’s altitude block in Albuquerque, which sits at 5,335 feet. Training partner Brannon Kidder towed him through the first two laps in 55.72 and 54.85, passing 800m in 1:50.57, near the record schedule. Kerr then ran the final lap alone in 51.88. Once he heard the time from his coach, Danny Mackey, Kerr told the camera he could go straight back to the line and run another lap in 60 seconds. LetsRun.com, which first assembled the full splits, reports that no one has beaten 2:44.75 for 1,200m within an official race, a split El Guerrouj set during a 1,500m in Rieti in 2002, according to Track & Field News data.

The mark carries qualifications that Kerr’s camp has made no effort to hide. He took a running start, the time was taken by hand, and a solo trial carries none of a race’s demands. Pulling in the other direction is the thin air. John Kellogg, LetsRun.com’s conversion specialist, values Albuquerque’s elevation at three to four seconds over a full mile and rates the session as worth a 3:41 mile at sea level. “Josh Kerr can run 3:42 at a very minimum,” he said.

The plainer arithmetic needs no conversion chart. Record pace reaches 1,200m in 2:46.37. Starting from 2:42.45, Kerr could cover the closing 409m of a mile in 60.6 seconds and still finish under El Guerrouj’s time, and he had just run his third lap, at altitude, in under 52. His limiting factor Saturday, on this evidence, is unlikely to be the finish.

The session also served as a rehearsal. Kidder is entered in Saturday’s race and, per LetsRun.com’s reporting, will again lead Kerr through the opening laps, meaning the pair have already rehearsed the assignment once. “I haven’t missed a day,” Kerr said at Friday’s pre-meet press conference in London. He was more direct about the assignment in an interview with FloTrack: “My competitor was a time that isn’t going to change.”

The record’s own history favors a crowded final lap. When the mark last fell, Noah Ngeny finished 3:43.40 behind El Guerrouj in Rome, also inside the old record, according to World Athletics’ report of the race, and Kerr has said that race is the reason he built London as an open competition rather than an exhibition. Yared Nuguse, whose 3:43.97 American record sits 0.84 seconds from the mark, is entered and intends to follow the pace. The Emsley Carr Mile starts at 3:36 p.m. BST (10:36 a.m. ET), live on the BBC in the U.K. and on FloTrack in the United States.