Kenyan Olympian Faith Kipyegon attempted to be the first woman ever to run a mile in less than 4 minutes Thursday, and research from the University of Colorado may have helped her efforts.

Although Kipyegon did not achieve her goal, she did run it in 4 minutes, 6.42 seconds, which is faster than the women’s world record mile time she set in 2023 at 4 minutes, 7.64 seconds.

Her attempt comes four months after CU researchers published a study hypothesizing Kipyegon could achieve a sub-4-minute mile under the right conditions. The study found that if Kipyegon could reduce the air resistance around her by 70% using pace runners and given her physical fitness level, she could run the mile in 3 minutes, 59.37 seconds.

Study author Rodger Kram, a CU associate professor emeritus in integrative physiology, said he was disappointed Kipyegon didn’t break the 4-minute mile and was surprised by the formation of the pace runners. The formation of the pacers around Kipyegon was intentional, using a concept called drafting, which is a way to use other runners to block the wind.

“That drafting formation was just so wide open, I’m really surprised if that’s what they were hoping for,” Kram said.

Kipyegon didn’t appear upset that she didn’t break 4 minutes. After the race, she told a reporter that it’s only a matter of time before a woman reaches that milestone. She said by getting so close, she has proven that it’s possible. Kipyegon added that she doesn’t plan to give up on her goal and wants to prove to the world that women are strong.

“I feel good; I’ve tried,” Kipyegon said after the race. “That’s why I’m coming here, to try to be the first woman to run it under 4 minutes.”

Kipyegon is the women’s world record holder for the 1,500-meter and the mile, and she’s a three-time Olympian and three-time world champion in the 1,500-meter race.

She won a gold medal in the 1,500-meter event in the 2016 Olympics in Rio de Janeiro, the 2020 Olympics in Tokyo and the 2024 Paris Olympics.

She also gave birth to her daughter before the Tokyo Olympics.

Kipyegon ran her attempt in Paris about noon Thursday Mountain Time. A strip of green lights on the ground of the inner curve of the track helped keep her and her 13 pacers on time. Announcers said the formation of the pacers was intentional, describing it as “the shield” around Kipyegon to reduce air resistance.

“The purpose of drafting is to reduce the air resistance,” Kram said. “It’s pretty easy to imagine a runner in front of you who blocks the wind and pushes the air out to the side. It turns out that a runner behind the designated runner also helps to reduce the air resistance because it makes the whole team of three, in this case … it makes them like a longer, thinner object so the air tends to flow around the group of three better than it does around the group of one or two.”

Kram said drafting principles also were used when Eliud Kipchoge of Kenya became the first person to run a marathon in less than 2 hours in 2019.

Although Kipyegon beat her own world record Thursday, the race was not eligible for official world record recognition because of the nature of the event, which was sponsored by Nike and included male pacers.

When Kipyegon ran her race, Kram said the spacing of the pacers’ formation seemed too wide. It didn’t seem like they were close enough to her. He hopes Nike reveals what led to that specific formation.

Kram also said people vary a lot in how much energy it takes to counter wind resistance. It may be that when she runs solo, she doesn’t use much energy to overcome air resistance, and so maybe drafting doesn’t help her as much. He doesn’t know if Nike tested her response to drag force.

The researchers sent her a copy of the paper out of respect and to pique her interest in the idea of breaking 4 minutes.

Kipyegon told The New York Times in February that she found the CU study to be “interesting.” She added in her statement, “I appreciate people taking my world record performance as an inspiration to imagine what could be possible in the future.”

In April, the authors found out she was going to try to break 4 minutes on the mile. Kram said it’s unusual to have a hypothesis tested so publicly, adding that it was a little scary.

“But on the other hand, it’s a fantastic opportunity,” Kram said. “How many people get to have their hypotheses tested by the world’s greatest middle-distance runner in history? It’s fantastic, and I’m a bit overwhelmed.”