Olympians are approaching the limits of human performance

“It’s part of who we are as a species to push limits and to push beyond what we think we’re capable of doing,” University of Oregon physiology professor Brad Wilkins said. “It’s probably part of why our species survived as a species — because we were driven to go further and build things and do things our Neanderthal counterparts weren’t able to do. I do believe a human is limited. But humans are not.”

Searching for the unbreakable barrier

In its December 2008 issue, Journal of Experimental Biology published an article with this title: “Limits to running speed in dogs, horses and humans.” It was written by a Stanford marine biologist named Mark Denny who had set out to test a theory. He expected to find the rate of world records correlated with human population. “In my lifetime, human population has more than tripled,” Denny said. Breaking barriers, he assumed, was strictly a matter of probability.

“Well,” Denny said, “the stats don’t show that.”

Denny took a novel approach. He mined data on thoroughbred horses and racing greyhound dogs. Starting in the 1960s and ’70s, he said, their performance had plateaued. As breeders pushed for greater speed, the traits that made the animals faster also made them too fragile.

Paris Olympics medal tracker

“They just break,” Denny said. “At some point, humans are going to run into the same thing.”

Denny paired the data from racing animals with reams of track and field official records. With no consideration for mechanics or physiology, he created a model that predicted when the curve for humans would match the animals’ speed plateau. For every major track distance, both men and women, he affixed what he asserted were the fastest times humans would ever be able to run.

The absolute 100 meters, his analysis showed, was 9.48 seconds. The women’s 800? It would never be run faster than 1:50.83. In the more than 15 years since Denny’s paper was published, just one of his absolute records has been surpassed: Four women, led by Tigst Assefa’s 2:11:53 in 2023, have run a marathon faster than 2:14:57. Denny pointed at a relative dearth of data from the era when competitive women’s marathons were rarely held.

“Things that on two legs versus four legs, things that weigh half a ton versus things that weigh 30 to 40 pounds, it says that there’s something going on here that is universal, at least among mammals,” Denny said. “It confirmed that humans just aren’t exceptional when it comes to athletic performance.”

Denny roots for athletes to break the absolute records, and he acknowledged his consideration of statistics alone made the article, sophisticated as it may be, mostly “fun with numbers.”

The physiological approach to determining a limit is multifaceted. At the highest level, even physics constrains humans. “The faster you go, the greater is the retarding force of the air resistance,” Jones said. “If you can improve your power by a couple of percent, that doesn’t mean you go a couple of percent faster.”

Peter Weyand, the director of Texas Christian University’s Locomotor Performance Laboratory, specializes in studying sprint speed. He refers to sprinters as “force application machines.” For something we do without thinking about, locomotion is remarkably complex, a tangle of bodily systems working in unison. What speed distills down to is how hard a sprinter can strike the ground relative to his weight.

Sprinters control two variables: the time their foot stays on the ground and the force their muscles apply to the ground. The only way to shrink that time is to apply greater force. If Weyand knows a sprinter’s contact time and the length of his leg, he can predict with uncanny accuracy how fast he is running. He is hesitant, though, to place a number on the fastest possible combination.

“Is it faster than the current world record? Of course it is,” Weyand said. “Bolt already did that, and there’s no such thing as a perfect race. Bolt on his perfect day could have run faster than 9.58. How much faster? I don’t know.”

The factors that limit sprinters differ from those that limit distance runners. Endurance performance is fundamentally governed by an athlete’s maximal oxygen uptake, called VO2 max — how much oxygen a person can use during exercise. An athlete’s VO2 max is analogous to a car’s engine size. Training can improve it — but only to a point. The highest VO2 max, which measures milliliters of oxygen consumed per minute per kilogram, ever recorded for a man is 97.5.

“It’s hard to imagine how or why we would have higher values than that in 10 or 20 years, at least naturally,” Jones said.

In a 1991 paper, Michael Joyner studied elite distance runners and determined the best possible VO2 max, lactate threshold and running economy. If a runner could achieve all three at the same time, he stated, the fastest possible marathon would be 1:57:58. Joyner, an expert in human performance at the Mayo Clinic, still sticks to his calculation, with the actual record currently at 2:00:35.

“Right now, we’re seeing a lot of world records being set or broken primarily due to technology first, sociology second,” Joyner said. “And I don’t think the athletes are physically better than they were 20 years ago.”

Finding better ways to be faster

In analyzing the progression of athletic achievement, two sports that use a clock, fixed distances and minimal equipment beg for comparison. The data makes it clear: Top performances in running have plateaued compared with swimming. In the past decade, swimming world records have been broken 43 percent more often per event than in individual Olympic track races.

The best Olympic performances highlight faster progress in swimming. In individual track races, none of the Tokyo Olympic champions in 2021 won with a time more than 6 percent faster than the 1972 Olympic champion. Meanwhile, every individual swimming gold medalist in Tokyo posted a time at least 7 percent faster than the 1972 champions; in 10 events, they were at least 10 percent faster.

Swimmers, like runners and throwers, have benefited from technological advances: better suits, improved pool gutters that reduce turbulence, deeper pools that allow faster swims. But experts see the difference between the sports lying in the utilization of technique.

“Swimming is such an unnatural thing for humans — land-based creatures — that I’d say humans in water are still evolving,” American Swimming Coaches Association adviser Russell Mark said. “We’re still learning. We’re still figuring out best practices and best things to do. Running has evolved ever since people have existed. We’ve had a lot of time to perfect it.”

At last year’s world championships, Frenchman Leon Marchand shattered the last record Michael Phelps held, a 400-meter individual medley time that had stood since 2008. Marchand weaponized underwater kicking, which Bowman said is the feature “that’s probably having the most impact now” in swimming technique. “That’s Leon’s thing. That’s something we’re just starting really to understand.”

It’s not that individual runners can’t improve their form — Lyles’s rigorous work on his starting technique has enabled him to take aim at Bolt. But today’s runners can’t reinvent form the way Marchand has.

“If you can find people who have freakish genetics, that’s great,” Jones said. “On the nurture side, I’m not sure there’s much more we can do in terms of training.”

Swimming’s capacity for improvement may only grow as data-tracking technology improves. Track coaches already use motion-capture sensors that send immediate, granular data — the angles of joints, velocity out of the blocks, foot contact time on the ground — to a coach’s iPad. Swimming is scratching the surface of how similar devices could help athletes, for exactly the reason one would expect.

“Water is undefeated,” said Mike Levine, the U.S. Olympic and Paralympic Committee’s director of performance innovation. “Sensors come off. They’re permeated by water, so they just break.”

It’s gotta be the shoes? Well …

The idea that technology is pushing forward human performance is not new. “I’ll tell you why men are running 100 yards faster today than they did years ago,” Jim Thorpe wrote in an article published in the Rotarian in 1940. “It’s not that one human body is more perfect than the other. It is the outside factors.”

It is not difficult to find experts who believe that human performance on its own has peaked and that improvements have derived from technology that supports performance, whether in competition or training.

“If you were to put that group of people from the ’50s and put them in the conditions with the technology and the time that the other athletes have been at this today, and the strategies they’ve been using throughout their careers, I think we would see the same times,” said Wilkins, the Oregon physiology professor. “I don’t think humans in particular have adapted in any way between the 1950s and now to have some fundamental changes in their physiology.”

In a 2014 speech, author David Epstein described a biomechanical study designed by sports scientist Ross Tucker. Based on the speed of Owens’s joints, the study showed that if Owens — with the training and nutrition available in 1936 — ran on the same track as Bolt, he would have finished a single stride behind Bolt on the day of his world record 100-meter sprint. In 1981, without modern suit technology, modern pool design or even goggles, Mary T. Meagher swam the 200-meter butterfly in 2:05.96, a time that would have advanced her to the Olympics at this year’s U.S. trials.

“People have been training as hard as possible, at least some of them, since the 1950s and certainly since the ’60s,” Joyner said. “Their lab values show that they’re not any different from what we see today. So what’s happened? The races happen at the best times. The tracks are way, way better. People have longer careers — remember, it was amateur hour.

“Go watch Bob Hayes run 10 flat on a dirt track. And he was 21 years old, and he was playing football. What do you think Bob Hayes could do if he was training full time for track, not getting beat up in the fall?”

One pursuit explored and exposed those questions: the Breaking2 project, Nike’s attempt to engineer a marathon completed in less than two hours.

In 2016, Nike signed world record Kenyan marathoner Eliud Kipchoge and two others to contracts that made them the hub of a performance experiment. A team of engineers, scientists and physiologists — including Wilkins and Jones — designed ideal conditions for a private race with the goal of breaking a two-hour marathon.

Breaking2 implemented a dividing line: Any technology that introduced energy into the runners’ system would be prohibited. Technology that prevented the dissipation of energy within their system would be permitted.

“Technologies that remove barriers and allow us to reach our true potential, I do not consider doping,” Wilkins said. “I consider that our natural way of performing and optimizing our own true potential.”

Runners ran around Kipchoge in an arrowhead formation to reduce wind resistance. A car drove in front of the runners with a clock mounted on the roof, keeping a constant pace.

The most lasting effect came from the shoes Kipchoge wore. The Nike Vaporfly would change distance running forever. The combination of a thick foam sole and a carbon plate created a springlike effect and made runners naturally more economical. Wearing the shoe reduced runners’ energy costs by 4 percent, Jones said, a remarkable gain in efficiency.

Middle-distance and distance records have been rearranged. In the women’s 5,000 meters, as one example, Ethiopian Tirunesh Dibaba’s 2008 record of 14:11.15 lasted more than 12 years. Since 2020, four runners have surpassed her time, with countrywoman Gudaf Tsegay lowering the record last year to 14.00.21 — an 11-second plummet in three years after a dozen years of stagnancy.

In swimming, high-tech suits that increased buoyancy and reduced drag upended records in 2008 and 2009 before the sport’s governing bodies banned them. They still show how technology can be powerful even when it can’t be used in competition. In 2016, as Phelps prepared for the Rio de Janeiro Olympics, he struggled with his underwater kicking technique. Nothing solved the problem until Bowman unearthed a banned full-body suit that Phelps had worn in 2008.

“As soon as he did a fast thing in that suit, he was like, ‘Now I remember,’” Bowman said. “It really impacted his swimming when he took the suit off. He could really get a feel for what it was like to be that fast and have that motion. The suit gave him that proprioception.”

At the conclusion of the Breaking2 project, Kipchoge finished the race in 2:00:25, falling less than half a minute short. In a similar exhibition in 2019, he broke the two-hour barrier.

At the 2023 Chicago Marathon, Kenyan Kelvin Kiptum reset the official record to 2:00:35, just 10 seconds slower than Kipchoge’s first sub-two-hour attempt. That time, many who worked on the Breaking2 project believe, was made possible by Kipchoge showing what could be done.

“It’s not your legs that run,” Kipchoge once told Wired magazine. “It’s your heart and your mind.”

All records start with a vision

Lyles first decided he could sprint 200 meters faster than anyone ever when he was a freshman at T.C. Williams (now Alexandria City) High. At a district meet at Lake Braddock High, Lyles won the 200 in 21.2 seconds. The time fulfilled his goal of shaving one second each year. His mother had also been a sprinter, and one of her old track coaches called Lyles and asked, “Do you realize that the time you just ran was the exact time Usain was running at your age?”

“I didn’t realize this goal I had set was such a high standard compared to everything else and everybody else that has gone on this path before me,” Lyles said. “At that moment it was like, ‘Okay, if I’m going after this goal, I’m going to have to get myself into the mindset that I’m going to have to attempt things from this age on that nobody has ever seen or even done.’”

For those with the physiological baseline necessary, trying to extend human performance also demands a psychological requirement. Lyles inspires himself through outlandish bombast. Phelps focused on the granular.

In 2003, Phelps muddled through the first two days of a midseason meet in Santa Clara, Calif., not even bothering to shave his leg hair. On the final day, Bowman sensed him perk up. As Phelps warmed up, Bowman gave Phelps target times for each leg of the 200-meter individual medley. Phelps started doing the math.

“That’s faster than the world record,” Phelps told him.

“So?” Bowman replied.

Phelps swam the race in 1:57.94, which broke a record that had stood for nearly nine years.

“It’s more a focus on maximizing what they can bring to the table,” Bowman said. “If they have talent and they’re well-trained and all these other things happen, that pushes them past these records. The records are kind of a nice milestone and a nice validation of the process.”

Before he first broke the shot put world record, Ryan Crouser had been throwing past the mark in practice for three years. At least five times, he arrived at a track meet certain that “the world record was in the bag,” he said. “And then I would get there. I would get a little bit tight. I wasn’t relaxed. You get a little bit of tension, you don’t hit those same positions.”

At the 2021 U.S. Olympic trials, Crouser surpassed a mark that had stood for 31 years. With that weight lifted, Crouser broke it again in 2023, at a midseason meet. The men’s discus record stood for nearly 38 years until it fell this spring, and no man has broken a world record in the javelin since 1996 or the hammer throw since 1986. Apart from Swedish pole vaulter Mondo Duplantis, who has upped the world record by a centimeter eight different times (which maximizes financial bonuses), men’s jumps have had a similar dearth in records.

Humans can be confounding creatures. In the 100-meter final of the 2008 Olympics, as he left his competitors in his wake, Bolt peeked over his shoulder and spread his arms in celebration with roughly 20 meters left. He lowered the world record to 9.69 seconds, but Denny believes he could have matched — if not beaten — 9.48 seconds.

“It’s so many little things like that that are going to set these things — not just performance but mental behavior as well,” Denny said”

Lyles rejected the very idea of a limit. Presented with the premise that a sprinter will never run 100 meters in, say, five seconds, Lyles wondered what humans could accomplish an eon from now. He was then asked how much further Bolt’s 200-meter record could be pushed.

“I plan to run 18.6 by the time I leave,” Lyles said. “Or at least that’s the idea I’m going to have in my head. I just want it to be so that it’s not going to be broken for 1,000 years.”

Lyles had not read Denny’s article. If he had, he would have seen the scientist’s prediction produced for the fastest possible 200-meter race: 18.63 seconds.

For athletes, it’s about the chase

When Denny’s paper was published, the prevailing response he received was anger at the notion of a human limit.

“People were upset with the thought that you could watch the Olympics and nobody was going to break the world record,” Denny said. “With things that are measurable, I think people just have it in their head that records were meant to be broken, and they will always be broken. Logically, that can’t be true.”

Even in such a dystopian scenario, the act of training and competing would remain profoundly human. When the first Breaking2 project ended, Wilkins left with a changed perspective. It had nothing to do with training or technology. It was about how Kipchoge lived.

Kipchoge, a multimillionaire with access to cutting-edge training science, lived away from his family for months with his partners in a minimalist house. They did their own cooking, washed their own shoes and took turns cleaning the camp. They didn’t use the GPS watches they were given.

“Eliud almost put himself in a condition where he had to suffer because he knew that suffering was the path to becoming more mentally prepared and more physically prepared to perform these really amazing feats,” Wilkins said. “In my mind — maybe this is just a story I tell myself — it’s all about suffering and knowing that’s the way you’re going to be better.”

Unsettling as an end point to human performance may be, the futile effort to advance beyond it confers a certain honor. To struggle against inevitability, after all, is merely a feature of the human condition. The real point is to try.