Faith Kipyegon’s attempt to become the first woman to run a mile in less than four minutes came up 6.42 seconds short Thursday, with the combination of Kipyegon’s speed and a complex system of pacemakers not enough to overcome a barrier that still has never been broken.

Kipyegon, a three-time Olympic gold medalist in the 1,500 meters who is considered the greatest middle-distance runner of all-time, finished in 4:06.42 in Paris in what is the fastest mile ever run by a woman. Although it bettered her world record of 4:07.64, run in 2023, her time will not count as an official world record given the extraordinary set of assistance — including male pacers — used during the specialized race organized by Nike and her sponsor and run in front of a limited crowd at Stade Charlety.

Kipyegon entered as the only woman to run a mile in less than 4:10, and in an attempt to knock off the 7.64 seconds separating her from history, Kipyegon ran alongside a team of 13 pacers using a carefully scripted choreography and formation to help the 31-year-old Kenyan “draft,” or reduce the amount of wind resistance she faced. To make Kipyegon even more aerodynamic, Nike created a specialized speed suit and sports bra and produced a new set of spikes.

Her coach, Patrick Sang, said on a Nike-organized broadcast before the race that Kipyegon appeared “a bit nervous” when he saw her Thursday morning.

Her attempt in Paris was not considered an impossibility because science suggested a sub-4 run was possible. In February, a team of researchers published a paper that modeled a race in which Kipyegon would stay within 40 inches of one pacer in front of her, and 40 inches in front of another behind her, with a new pacing team swapping in halfway through. With that drafting strategy, the researchers concluded, Kipyegon could run 3:59.37 — the exact time run by Roger Bannister in 1954 when he became the first human to break the sub-four-minute barrier.

Nike did not consult with the researchers on the design of its drafting strategy. Instead, it employed pacers stationed in front of Kipyegon, to her right and behind her, to create a “pocket” of less drag. Five ran in front as a “shield.” The pacers included Grant Fisher, an American two-time Olympic bronze medalist. She reached the halfway point in 2:01.7, and with one lap to go she had run 3:01.84. As the race progressed, pacers dropped off, leaving five with her as she entered the final straightaway.

In the days leading up to the race, one of the researchers who co-wrote the paper outlining the sub-four possibility said that even if Kipyegon did not dip under four minutes, the run could still be considered a step forward in understanding the possibilities of women’s running. The researcher, Shalaya Kipp, a postdoctoral research fellow at the Mayo Clinic and former Olympic distance runner, compared Kipyegon’s run to when Nike staged another “moonshot” race in 2017 to help Eliud Kipchoge become the first person to run a marathon in less than two hours. His first attempt fell short, but Kipchoge eclipsed two hours on his second.

“Is it really going to be a failure if she runs, you know, 4:01, 4:02? It’s still going to be a big deal,” Kipp told NBC News last week.“That’s how Eliud Kipchoge’s first sub-two [marathon] attempt was. It wasn’t perfect, but it lowered the standard, and it made us realize if we can get closer, we can do it.”