I wish I knew something about online sports betting. I don’t. But someone could clear a nice chunk of cash on the upcoming Nike Breaking4 project.
On June 26 in Paris, Nike runner Faith Kipyegon will attempt to break 4:00 minutes in the mile for an exhibition 1-mile race sponsored by Nike.
The company is hoping to build on the concept it launched in 2017 when Eliud Kipchoge ran the Breaking2 marathon in 2:00:25. Two years later, in a similar event sponsored by another company, Kipchoge ran 1:59:40.
The sub-4:00 mile represents the biggest, most historic barrier in all of sports. When Roger Bannister ran 3:59.6 at Iffley Road Track in Oxford, England, on May 6, 1954, he became the most famous runner of all time. For all time.
However, Kipyegon won’t be following in Bannister’s footsteps. She has little to no chance to break 4:00. Bet against her.
As a sports-mad youngster, I spent hours listening to an LP record featuring the greatest moments in sports history. You know: “The Giants win the pennant! The Giants win the pennant! The Giants win the pennant!” Stuff like that.
My favorite moment by far was a sentence uttered by Norris McWhirter, who would later co-found The Guinness Book of World Records with his twin brother, Ross. Norris was the track announcer at Iffley Road on Bannister’s big day. After the race, he intoned:
“Ladies and gentlemen, here is the result of event nine, the one mile: first, number forty-one, R. G. Bannister, Amateur Athletic Association and formerly of Exeter and Merton Colleges, Oxford, with a time which is a new meeting and track record, and which—subject to ratification—will be a new English Native, British National, All-Comers, European, British Empire, and World Record. The time was three…”
No one heard another word. Or needed to. This phrasing gave me goosebumps when I was 14, and it still does today.
The Electronic Era and 5-Digit Mile Times
There will be no such announcement on June 26 in Paris. We live in a digital age, and the LED scoreboard will flash Kipyegon’s time in a millisecond. It will have five digits—x:xx.xx—to Bannister’s four. The first digit will not be a 3.
In a moment, I’ll explain. But first, let me acknowledge that Kipyegon is the greatest female middle-distance runner of all time. She has won gold medals in the last three Olympic Games—2016, 2020, and last summer in Paris. No one else—male or female—has achieved that distinction.
She also holds the world record in the mile at 4:07.64 and at 1500 meters in 3:49.04. The two are roughly equivalent. She’s consistently fast.
Kipyegon is a member of the famous Kalenjin tribe of elite runners in Kenya. She lives and trains at a no-frills, high-altitude camp in the Rift Valley—the same camp as Eliud Kipchoge. She also has the same coach as Kipchoge and appears to share his mental focus.
Kipchoge has said, “No human is limited.” Kipyegon says, “It’s all about the mind. If you keep on telling yourself that you can do it, you can do it.”
Kipyegon Has a Numbers Problem
Maybe. But Kipyegon, who is just 31 and therefore still at full power, has a numbers problem. You can’t break 4:00 minutes with your mind alone. Elite milers must push the heart, lungs, blood, and bones to extraordinary limits. Kipyegon simply doesn’t have the physiologic capacity required to run sub-4:00.
She just opened her 2025 racing season. At the Wanda Diamond League Meet in Xiamen, China, Kipyegon ran a sparkling 2:29.21 for 1000 meters, missing the world record by just 0.23 seconds. It seemed a good omen for Breaking4.
Except the math doesn’t work. According to World Athletics’ Scoring Tables, Kipyegon’s 1000-meter time is roughly equivalent to a mile time of 4:12.70. Oopsie.
To run a 3:59.9 mile, Kipyegon should be able to run 800 meters in about 1:51–1:52. In real life, her best 800 is 1:57.68. She’s tied for 651st place on the all-time list. This is, to put it frankly, not a good starting point from which to attack a sub-4:00 mile.
What Science Says About the Sub-4:00 Female Mile
Running scientists have been debating and exploring the female sub-4:00 mile for some time. One wrote: “Human beings appear hardwired to attempt to break barriers, and we perceive the most significant barriers to be those in the round number format.”
Like, for example, the 2-hour marathon and the 4-minute mile. Nice, round numbers. Easy to understand and to chase after. Runners enjoy the quest, fans enjoy the excitement, and top scientists can’t refrain from speculating.
Recently, several well-known running biomechanists attracted attention by switching to aerodynamics (drafting) and predicting a female could run 3:59.37 in a perfectly paced race (Royal Society Open Science).1Silva, Wouter Hoogkamer, Kipp, S., & Kram, R. (2025). Could a female athlete run a 4-minute mile with improved aerodynamic drafting? Royal Society Open Science, 12(2). https://doi.org/10.1098/rsos.241564 They noted, however, that effective drafting in the mile requires extraordinary precision.
“The athletes would need to devote significant practice time to coordinate the choreography of their movements,” they wrote. Indeed, there should be exactly 1.3 meters between the front pacer and the chosen runner, and another 1.3 meters to a rear pacer. We’ll return to this shortly.
An even newer paper (Journal of Applied Physiology)2Osborne, R. J., Kirby, B. S., Black, M. I., Vanhatalo, A., & Jones, A. M. (2025). Seven (.65) Seconds Away: The Possibility and Physiology of a Women’s Sub-4 Minute Mile. Journal of Applied Physiology. https://doi.org/10.1152/japplphysiol.00074.2025 predicted that a sub-4:00 female looms on the horizon. Depending on how and when you draw the progression lines, it “is projected to occur in 2030, 2038, or 2065.” Don’t hold your breath.
The authors of this paper include Andrew Jones, famous for his work with Paula Radcliffe and the Breaking2 marathon project. Also, surprisingly, a Nike physiologist named Brett Kirby. Maybe no one in Nike’s marketing department told Kirby about this year’s Breaking4 attempt?
Jones, Kirby, and colleagues make several blunt points. Here’s one: “To our knowledge, there is no female athlete presently displaying the endurance characteristics required to run a sub-4 min mile.”
Here’s another, which echoes what I wrote about 800-meter times: “Moreover, 800m performance amongst the world’s best women presently appears insufficient to suggest that a sub-4 min mile is imminent.”
A decade ago, in the pre-super-shoe era, top running physiologist Carl Foster wrote a paper (International Journal of Sports Physiology and Performance)3Foster, C., de Koning, J. J., & Thiel, C. (2014). Evolutionary Pattern of Improved 1-Mile Running Performance. International Journal of Sports Physiology and Performance, 9(4), 715–719. https://doi.org/10.1123/ijspp.2013-0318 noting that mile times have gotten faster due to better pacing. The key: an even-pace strategy. Anything else is simply wasteful, and there’s no room for waste in a fast mile. For example, Hicham El Guerrouj ran his long-standing mile record (3:43.13 in 1999) with splits of 55.6–56.0–56.3–55.2.
Key Differences Between Kipchoge-Breaking2 and Kipyegon-Breaking4
Nike created both the 2017 Breaking2 marathon project and this year’s Breaking4 female mile project and would like us to believe them similar. They aren’t… unless you happen to think that 26.2 miles and 1 mile are about the same distance and require the same physiologic makeup.
In Breaking2, Nike had a sensational new energy-conserving shoe it wanted to tout. Also, the marathon distance allows runners to play around with other factors like pacing, fluids, and gels. Kipyegon may or may not be wearing new shoes—we’ll consider options in a moment—but she doesn’t need fluids or gels, and mile pacing is much more intricate and exacting.
Another big difference between Breaking2 and Breaking4: In his two exhibition marathons, Kipchoge improved by 1.35%, from 2:01:18 to 1:59:40. Kipyegon is aiming to run 3.08% faster than ever before, from her current world record of 4:07.64 to 3:59.99. That’s a much bigger leap forward.
No doubt Kipyegon will be using sodium bicarbonate, and probably already was in 2023 when she set her current record. Caffeine? Of course. And I imagine she’ll be wearing super shoes tested and honed to her precise running mechanics. It doesn’t matter if the shoes are legal or not, since no one’s pretending that these “exhibition” races deserve world record status.
They don’t. They’re expensive advertising buys—nothing more. Which is fine, as they are also great fun and have enlivened the sport. I’d be happy to see more.
World Athletics currently limits track shoes to a stack height of 20mm—half of what is permitted on the roads. I assume Kipyegon will have a thicker, highly responsive foam underfoot, along with whatever carbon plates she prefers.
The Pacing Conundrum: Do You Want Men Leading the Way?
Shoes and supplements could certainly help Kipyegon run faster than ever before. But they won’t get her all the way to a sub-4:00.
This brings us to the pacing question, where the details get interesting. As noted, perfect pacing can produce a dramatic benefit by reducing the “drag” of air resistance. But it is tricky to achieve in a fast mile race.
Here Nike and Kipyegon face an “optics” question. There are about a million male runners who can easily run 1:59 for 800 meters. They would make great pacers.
But I doubt either Nike or Kipyegon want to organize a race dependent on men. That just wouldn’t look right for the occasion. Women can only run sub-4:00 if men lead the way?
Meanwhile, there are only a handful of Nike women who can cruise a 1:59. Will they be imported to assist Kipyegon by running 800 meters just ahead of her, and just behind her?
Or will Nike need to use a larger contingent of 400-meter runners who will swap in and out each lap? More runners equals more need for precise choreography and more room for error.
The Challenge of Supra-Max Racing
Nike is a big company with a lot of resources, but it can’t change human physiology. And there’s a huge, undiscussed difference between the marathon and the mile. The marathon is a sub-max event; the mile is supra-max.
Here’s what this means: In his marathons, Kipchoge ran at a pace equivalent to about 88 to 92 percent of his VO2 max. Since this is less than 100 percent, physiologists term it sub-max. For most of us, it’s about the effort we can maintain for an hour of steady, hard running. We often call it a tempo-run pace or lactate-threshold pace.
At his best, Kipchoge could maintain this pace for two hours, which is one reason he set world records, and the rest of us didn’t.
Marathoners Are From Venus, Milers Are From Mars
The best milers perform in an entirely different “domain,” to use the physiology term. They have to aim for 110% to 115% of their pace at VO2 max. No one would ever call this a pleasant tempo or steady-state run.
In fact, it’s ugly. Bad stuff happens when you run this hard: You become anaerobic, accumulating excessive amounts of blood lactate and hydrogen ions. These quickly begin to limit your muscle contractions and efficiency. Your heart rate reaches its max; your breathing frequency soars (hyperventilation); and your brain sends out panic signals demanding that you slow down.
You want to quit running. Right now!
These things don’t apply to the marathon, where gradual dehydration and loss of energy supply can be partially offset by drinking and eating. Kipyegon will be battling fiercer biologic foes.
She will have to push her limits almost from the first stride. That comes with great risks.
The biggest? If you mistime your effort, particularly if you start too fast, you set off a cascade of metabolic processes that will bite you in as little as 15 seconds. If you struggle hard, you can last a couple of minutes more. But no longer.
Kipyegon’s Dilemma: How to Pace Her Breaking4 Race?
In my view, Kipyegon will face a sort of “Sophie’s Choice” in her Breaking4 race. She’s got two options, and both are bad.
If she covers the first lap in 62 seconds, what is that going to look like? (Not good: like she’s not really trying, like Nike perpetrated a fraud.)
So she’s got to start hard and fast. Then what happens?
In theory, she should aim to run laps of 59.5–60–61–59. This would give her a final time of 3:59.5 and an incredible new world record in the mile.
But theory is one thing, and a 59.5 first lap is another. If Kipyegon starts that fast, she’ll be running way beyond 100% of her VO2 max. Her body will react by producing excessive amounts of lactate, hydrogen ions, and other fatigue-inducing byproducts.
Runners have varied, colorful descriptions for what this feels like. A popular one: “Someone dropped a piano on me.” Unlike super shoes, pianos do not help you run faster.
And Kipyegon will still have three laps to go. I wish her well, but I can’t see how she ends up with a sub-4:00.
Two years ago, when Kipyegon ran her current world record 4:07.64 (YouTube), Kara Goucher provided TV commentary for NBC Sports. Afterwards, she said: “I never thought I’d see a woman go sub-4:10 in my lifetime.”
I hope Goucher lives a long time—long enough to see the first female sub-4:00 mile. But it won’t be this year.
You can bet on it.
If you want to take a look at what it takes to train to run a 4-minute mile, check out this guide:
Easy to say until it happens. The problem is you are coming at this from the wrong angle. The mile is a primarily aerobic event. It’s not about speed it’s about endurance. She doesn’t need 1:51 speed, she needs to be able to hold 1:59. That required endurance which is much more easily trained and improved upon than speed and the anaerobic metabolism which is limited. I say she does it. Maybe not this time out but within two years for sure. The other good thing about the mile is she can make another attempt almost right away. Lots of darts to try to hit the bullseye here.
Nice analysis, Amby. Reminds of the times we talked about running physiology a few decades ago. 😊 You’re correct in concluding that she isn’t physically capable of running sub-4 – with normal though perfected pacing. I suspect Nike will put 2-3 sprinters in front of her and replace them every lap. I don’t have the data to calculate the time advantage, but she might lower her time appreciably, but sub-4 is still a huge goal. Whatever time she runs won’t count for anything except publicity given the illegal pacing as was done in the sub-2 marathon.