Why Runners Are Racing Faster Than Ever

Uncovering the speed boom: endurance science experts reveal the secrets behind record-breaking runs

These days, every running fan is talking about the same thing: How are so many athletes running so fast at so many distances?

World records seem to be dropping every weekend, from the 1-mile to ultramarathon distances. A few of them: Jakob Ingebrigtsen, indoor mile, 3:45.14; Grant Fisher, indoor 5,000, 12:44.09; Jacob Kiplimo, half marathon, 56:42; Ruth Chepngetich, marathon, 2:09:56.

We all have our theories, prejudices or suspicions, but those have big limitations. To learn more, I decided to take a different approach. I asked 20 of the world’s top endurance running scientists (in physiology, nutrition, and biomechanics) to rank the reasons for the super-fast performances we’ve seen. I got answers back from 11 of them.

a group of people running on a wet road

What The Experts Say About These Fast Times

The rest of this article summarizes their responses and comments. The results could help you orient your own training to achieve maximal impact. 

First, here are the questions I sent the endurance experts.

What percent of the recent impressive running performances are associated with each of the below. Your responses should tally 100%. 

  • Race day super shoes
  • Regular training in super shoes, which improve both training speed and post-training recovery
  • Improved training methods such as double thresholds
  • Improved daily nutrition such as daily high carbs
  • High carb intake during endurance performance
  • More caffeine before and during races
  • Sodium bicarb before races
  • Ketones after workouts for various reasons
  • The post-Roger Bannister psychological effect, “Apres moi le deluge:” (the phenomenon where breaking a previously unachieved barrier—such as Bannister’s sub-4-minute mile in 1954—inspires others to quickly surpass it, demonstrating the power of psychological belief in athletic performance)
  • Other (This is deliberately an “open” factor , ie, whatever “other” means to you.)

A couple of notes. I forgot to include pacers and pacing lights. My bad. Several respondents noted these as possible factors supporting fast times. 

Few understood that my “other” question was designed to include doping. Again, my bad for being vague.

Some of the respondents provided answers that did not total 100%.

a close-up of legs and feet of a runner

A Surprise: The Endurance Science Experts Aren’t Afraid To Be Quoted

A final observation on what you’re about to see. I expected many scientists to be hesitant to make speculative judgments, and therefore offered them anonymity in terms of their questionnaire responses.

It turned out that few were as hesitant as I thought they would be. Nonetheless, I have still presented the table data in a randomized manner. You can’t match anyone’s name to the data in the Table. 

At the same time, I asked everyone for comments that could be attributed directly to them. Most readily supplied these, and you will find them below the table.

Okay, here’s the big table. This shows a birds eye view of 11 endurance running experts who answered the questions I sent them. One gave two sets of answers: one for mid-distance races, and one for longer distance.

What Percentage of Recent Fast Times Can Be Attributed to Each Of These Factors?

Why Runners Are Racing Faster Than Ever 1

* Two respondents answered: Mostly carbs for marathon and beyond races; mostly sodium bicarb for middle distance

Respondents: Geoff Burns, biomechanist, U.S.; Carl Foster, physiologist, U.S.; Bas van Hooren, physiologist (and 1:02 half marathon runner, Netherlands); Andrew Jones, physiologist, England; Steve Magness, physiologist and coach, U.S.; Gregoire Millet, physiologist, France; Max Paquette, biomechanist, U.S.; Philip Skipa, physiologist, U.S.; Trent Stellingwerff, nutritionist, Canada; Randy Wilber, physiologist, U.S.; Michele Zanini, physiologist, Italy.

In Their Own Words: Straight From The World’s Top Endurance Scientists

Geoff Burns: “Generally, my feeling is Shoes >> Bi-carb >> Psychology > Training > Race Execution > Nutrition, although nutrition is very important in the marathon and beyond. Super shoes plus bicarb might improve mile times by 3 to 5 seconds. In the 5,000, shoes plus bicarb might give an elite racer 12 to 15 seconds. 

“I would also note that better anti-doping practices have perhaps had a somewhat opposite effect, slowing some race results. More regulation has limited the rampant doping that likely inflated performances earlier, especially in East Africa. The relative rise of American, European, and Japanese athletes has happened during an era of super shoes and stronger drug testing. This is likely not a coincidence.”

Carl Foster: “Under ‘Other,’ carbon monoxide doping could be a 15% explanation for fast times, and pacers and pacing lights could be 10%. I think the value of training volume, as exploited by Lydiard, has run its course, and now we have returned to Zatopek 2 training.”

Andrew Jones: “I have a sneaky suspicion that exactly what you do in training might be less important than doing something/anything/whatever you prefer. Some of the faster times might come from the greater spread of talent in the sport, such as the rise of other African nations like Uganda.”

Steve Magness: “The high carb approach and bicarb are interchangeable. What I mean is: Higher carb loading helps in the marathon, but not in track. Bicarb helps way more in mid-distance events, and not that much in longer races.”

Gregoire Millet: “I am not so convinced about ‘double threshold’ theory. I am more prone to believe that altitude training or altitude chambers or heat training have become very important factors in endurance performance improvements.”

Max Paquette: “Performance studies show consistently positive outcomes with super shoes, especially at faster speeds and in more competitive athletes. There has been lots of anecdotal evidence that athletes report feeling better, less sore, less fatigued, and recovering faster when they train in advanced footwear shoes. They also seem able to withstand heavier training loads. Studies in our lab and elsewhere have provided some evidence for this, though mainly in elite athletes rather than recreational runners.”

Philip Skiba: “We cannot underestimate the effects of doping, given the number of positives in recent years.”

Trent Stellingwerff: “I think another important factor is the impact of internet/social media on training knowledge. In our day, it was almost impossible to know how others were training. Now, with Strava and other platforms, it is so much easier to see what the pros are doing. This helps many more people to make ‘high probability’ training decisions, and to avoid dumb mistakes.”

Bas van Hooren: “I think many nutrition things were known already for years, so I don’t think they have contributed that much, at least not for the elites who were already doing these things well.”

Randy Wilber: “When I started here at the USOC 32 years ago, there were just a handful of distance runners using altitude training, mostly in Boulder. Now, virtually every Team USA middle-distance and long-distance runner, including both males and females, uses altitude training and/or hypoxic training.”

Michele Zanini: “The materials used in track construction are getting better and faster. Also, funding to support athletes has grown and gotten more targeted.”

a hand on a track

What Conclusions Can We Reach From This Survey?

That’s not easy to say. Generalizations are only good in the general case, and aren’t guaranteed to improve anyone’s personal fitness.

But we’ll take a crack at several:

#1: First the experts believe that super shoes make a substantial difference in race times, which has become quite obvious. The experts also mostly believe in the positive effects of training in super shoes. The new shoes can help you train longer and faster, and recover better. This is no short-term fix, but can deliver strong benefits over several years. That might explain why so many are racing so fast a number of years after super shoes became widely available.

#2: Nutrition is event dependent. It’s becoming ever clearer that athletes can perform better if they can tolerate higher carbohydrate-intake during marathons, ultramarathons, tour races, and the like. Also, it might be possible to train your gut to accommodate more carbs, so it’s something you have to tackle in training.

Sodium bicarbonate is now considered a strong, and growing, factor in middle distance running. Grant Fisher has admitted to using it in his record races of 3,000 meters and 5,000 meters. Even some ultramarathoners are trying bicarb, though the research indicates it’s only effective in events lasting under 10 to 15 minutes. 

#3: When it comes to advances in training theory, like ‘double thresholds,’ expert opinion is divided. We’ve heard experts say that training at the highest elite levels hasn’t introduced anything new in decades. However, others give a nod to various training systems including double thresholds, altitude, heat, and cross-training for runners.

We like Andrew Jones’s comment, which is essentially: “Do as much as you can of the training you enjoy the most.”

#4: Finally, almost all our experts gave at least a few percentage points to the “Roger Bannister effect.” When someone or a handful of someones begin running fast, others start thinking, “Why not me?”

The mental side of running will be a forever factor, even as we struggle to define exactly what it means. To run your best, no matter where you are in the ranks, you need to hone your mental game.

a group of people running

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Amby Burfoot

Editor At Large

Amby Burfoot stands as a titan in the running world. Crowned the Boston Marathon champion in 1968, he became the first collegian to win this prestigious event and the first American to claim the title since John Kelley in 1957. As well as a stellar racing career, Amby channeled his passion for running into journalism. He joined Runnerโ€™s World magazine in 1978, rising to the position of Editor-in-Chief and then serving as its Editor-at-Large. As well as being the author of several books on running, he regularly contributes articles to the major publications, and curates his weekly Run Long, Run Healthy Newsletter.

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