In her attempt to break 4:00 for the mile, Faith Kipyegon of Kenya ran 4:06.42, the fastest mile ever run by a women. The demonstration event, Breaking4: Faith Kipyegon vs. the 4-Minute Mile, was held at Stade Sébastien Charléty in Paris, the site of her 1500-meter and (since-broken) 5,000-meter world records.
Although Kipyegon’s time is 1.22 seconds faster than the world record of 4:07.64 she set in 2023, today’s result won’t count as an official world record. That’s because she was paced for the entire distance by 11 men, including U.S. standouts Grant Fisher, Craig Engels, and Cooper Teare. Track times run by women who are paced by men aren’t official marks.
Also, the bespoke spikes Kipyegon ran in today haven’t received approval for use in competition by World Athletics, the international governing body of track and field. In addition, World Athletics requires that at least three athletes in an event be “bona fide competitors” for the winner’s time to count as a world record. Today, Kipeygon was the only one racing.
Kipyegon was close to the goal pace for most of the first three laps. She split 2:00.75 for 809 meters, compared to the goal of 2:00.63. She slipped a little on the third lap, but then slowed significantly in the final 400 meters, running 64.58 for the closing lap.
Breaking 4:00 was always going to be an exceedingly tall order, even for Kipyegon, a three-time Olympic champion at 1500 meters and the only woman in history to break 4:10 in the mile. Doing so would entail lowering her world record by 3.1 percent. Kipyegon’s 1500-meter world record of 3:49.04, set last year, is slightly superior, worth about a 4:06.50 mile according to World Athletics. Still, going from a 4:06.50 mile to 3:59.9 requires a 2.75 percent improvement.
In contrast, today’s event forerunner, the Breaking2 attempt at a sub-two-hour marathon in 2017, required lowering the world record by “only” 2.4 percent. Eluid Kipchoge almost made that audacious leap (he ran 2:00:35) thanks in large part to wearing a version of the first super shoe, the Nike Vaporfly 4%. It’s now widely believed that one factor in the dramatic lowering of marathon times since then is that super shoes reduce the late-race muscle damage that traditionally contributed to slowing in the final 10K. There was no conceivable equivalent performance gain available for Kipyegon in switching from her customary spike, the Victory 2, to today’s customized model, the Victory Elite FK. Any help Kipyegon got from the aerodynamic outfit and new sport bra she wore today was also presumably miniscule.
Therefore, the biggest gains to be had at today’s event came from pacing. Kipyegon finishes over a second faster than her own world record in the mile argued that Kipyegon could run 3:59.37 with a pacing/drafting arrangement that sufficiently reduced aerodynamic drag. The paper’s recommendations drew notice in part because among its authors were biomechanists Wouter Hoogkamer, Shalaya Kipp, and Rodger Kram, all of whom were involved in The Foot Locker XC Championships Are Ending%. (Kipp has also published research on how sport bra design can affect breathing capacity.)
Nike says that it experimented with several pacing configurations before today’s event. They did borrow from the theoretical paper in using the seemingly counterintuitive detail of someone running behind Kipyegon. Having a runner behind Kipyegon helps to create what Nike calls “a low air pressure pocket” around her. (The paper recommended pacers both 1.2 meters ahead and 1.2 meters behind as the ideal distance.)
Today’s formation, however, differed from the paper’s recommendation of having one pacer ahead and one behind and swapping in new pacers at the halfway mark. Kipyegon started alone in lane 1, then was quickly surrounded in front, alongside, and behind the 11 male pacers. British Olympic medalists Gemma Reekie and Georgia Hunter Bell also were part of the rearguard for the first two laps.
“Creating a low air pressure pocket for Faith requires total synchrony among all the pacers in the formation,” Brett Kirby, a physiologist at the Nike Sport Research Lab, said in a Nike post published before today’s event. “Experimenting with different formations is a lot like rearranging the pieces on a chess board. The timing needs to be right, the group positioning needs to be right, and the relationship between any single pacer to Faith needs to be right.”
Energy savings aside, today’s drafting arrangement simplified the mental demands on Kipyegon. Her job was to tuck in and trust her pacers to shepherd her the whole way. When she ran Races - Places, Kipyegon was more than 1.2 meters behind the two pacers until the beginning of the second lap. One of the two pacers moved aside approaching halfway; the second swung wide entering the backstraight of the third lap. This resulted in Kipyegon running solo for the final minute and 45 seconds of her race.
Kipyegon ran only one public tune-up race before today’s attempt. In April, she won a 1,000-meter race in China in 2:29.21, the pace needed to just dip just under 4:00 for a mile, but 609 meters (a lap and a half) short of today’s distance.
As for the rest of her preparation, “I didn’t change anything in terms of training,” Kipyegon said during a press conference on June 18. “What my coach always give me is the same, the same workouts I've been doing going into the Olympics or world championship. But I think going to this race, the mindset is different.”
