Mind and Muscle … How far and fast can humans run? What defines a human’s limits? … Lessons from Alex Hutchinson’s “Endure” for business leaders

April 29, 2020

I loved this book: Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance. Not just because it indulges my love of running, but because it’s about how to endure, how to go further, how to reach higher, how to achieve more.

From Malcolm Gladwell’s introduction (he’s a running fan too, and can still run a 5 minute mile) to Eliud Kipchoge seeking to break two hours in Monza (and subsequently did in Vienna), it uses the anecdotes and scientific facts of endurance sports, and can be applied just as easily to leadership in business.

Endurance as a human phenomenon involving far more than just muscle power.

There are actually  many physiological elements at play, from core body temperature to oxygen intake, as well as other psychological factors, such as perceived effort and pain tolerance. Each of these factors are significant in the level of athletic performance humans are capable of, especially in terms of setting new world records in sports like marathon running, cross-country skiing, and other feats of endurance.

Nearly every athlete will attest to faster recovery if they bathe in ice after a competition. However, studies show that this practice doesn’t actually decrease inflammation levels, the thing the baths are intended to reduce. The thing is though, if there’s a method that helps you recover, even if it’s purely psychological, it’s valuable to use it because sometimes belief is just as influential as science.

Sub-2 hour marathons, and the last minute of a mile

Most people can conjure up a vivid scene of a marathon runner crossing the finish line only to collapse to the ground, visibly shaking, covered in sweat, and barely able to function. When you witness these scenes, it’s easy to ask yourself, “How did they make it over the line? What kept them from collapsing a few minutes earlier?”

These are questions that the author, Alex Hutchinson, asked himself, ever since his grad-student days when he ran for the Canadian national team. Since then, Hutchinson has become an expert on endurance sports and has been able to discover how it is that human beings are able to push their bodies to the limit, climb to the top of the highest mountains, and cross those seemingly insurmountable boundaries of pain and effort.

Along the way, Hutchinson has unearthed intriguing scientific facts concerning just how far we’ve come in understanding the biology of endurance, especially as it pertains to the brain. Recent research has shown that the mind actually plays a very large instinctual role in sending signals to the body about when to pace itself and, on the contrary, when to shut down. As Hutchinson has discovered, something that might seen incredibly uncomplicated, such as running or riding a bike, in fact, is a fascinatingly complex process.

Endure Key Idea #1: Testing the true limits of human endurance can result in fatal consequences.

British explorer Henry Worsley liked to push himself beyond the normal boundaries of human endurance. One of these boundary-pushing expeditions started in late 2015 when Worsley attempted to walk across Antarctica alone. Although he did travel very far on this expedition, the journey started to take a serious toll on his body after 56 days. On the night of the 56th day, he was hit with painful indigestion, which prevented him from getting any sleep. This meant that the following day, Worsley tried to rest, but he still had 200 miles still to go, and he couldn’t afford to take too much time off. At midnight, with the polar sun still beating down upon him, he resumed his journey, the leg he was on involving climbing up the Titan Dome – a mountain of ice that peaked at 3,100 meters above sea level. Every step of the way, Worsley faced strong headwinds which drove sheets of snow against him as he struggled to breathe in the thinning air. After 16 hours, Worsley had to stop for another break. Just in case he had to call for help during this solo journey, Worsley carried a satellite phone on him at all times. This was something of a double-edged sword: while the phone could save his life, it also gave him a bit of a security blanket in that he felt so safe being able to contact people that he was pushing his body past its limit. At this point, he’d already lost 48 pounds in bodyweight. Remarkably, even in the dire situation he was in, Worsley would last more than another week before he finally decided to use the phone to call his rescue team. By this point, he’d walked for 70 days and was just 30 miles away from his goal. The following day, his rescue team picked Worsley up and and flew him to a hospital in Punta Arenas, Chile, where he was quickly diagnosed with dehydration and exhaustion. However, that wasn’t the worst of it — the doctors also found signs of bacterial peritonitis, an abdominal infection that would require immediate surgery. Things quickly took a turn for the worse. Due to the weakened state of his body, Worsley was unable to fight the infection, and on January 24, 2016, his organs shut down, leading to his death. This tragedy raised some important questions about the ethical and practical limits of expeditions that would require such intense boundary-pushing. However, plenty of humans have safely returned from unbelievable destinations like this, and in the book summaries ahead, we’ll look at the human body’s limitations, and why some feats are possible, while others simply aren’t.

Endure Key Idea #2: Out of instinct, we pace ourselves so that we can give that final push in a long distance run.

While the author was working on his PhD, he ran on the Canadian national team for middle- and long-distance races for. Eventually, he realized that at the end of each race, he would run faster, even though that wasn’t part of his strategy. He then wondered whether this was everyone’s experience with running. In 2006, researchers Tim Noakes and Michael Lambert published a study that followed the world’s greatest long-distance runners. Their findings showed a consistent pattern: while the runners would start off fast, the best ones would end up decreasing in speed during the middle of the race, only to accelerate again before finishing. This happened consistently, even though one might assume that their energy would be depleted by the end of the race. A casual observer would probably see this is a strategic decision by the runners, but it’s likely an evolutionary response in our brain. Sports scientist Dominic Micklewright of the University of Essex wanted to learn more about our ability to pace ourselves, wondering whether it was an instinct that develops at a particular time in our lives. Micklewright’s curiosity was inspired by Swiss psychologist Jean Piaget, whose studies were based on how childhood development is made up of distinct behavioral phases. So, in 2012, while working with children from age five to 14, Micklewright had the goal of figuring out when exactly it is that we develop the ability to pace ourselves. He noticed that children ages eleven and under would sprint at the start and get slower and slower as the race went on, whereas children eleven and olderwould pace themselves the same way the world-record holders did, by slowing down in the middle of the race and finishing with a sprint. According to both Micklewright and fellow sports scientist Tim Noakes, this pacing pattern is not a strategy, but is actually an instinct engrained in the human brain. They draw parallels to our time as hunter-gatherers, and believe that it developed so that we could run long distances during a hunt while conserving energy, in case we needed to finish the hunt with a final burst of speed.

Endure Key Idea #3: Having a tired brain can affect how much you can endure physically.

In 2013, Samuele Marcora traveled over six and a half thousand miles by motorcycle. This journey was between London and Beijing, a test of his endurance that doubled as a continuation of his long-term study of the mental component of physical effort. His trip from the UK to China reinforced Marcora’s belief that the mind is a big component when it comes to how much human beings can endure. In other words, fatigue isn’t just a physiological experience. Prior to this, in 2009, Marcora conducted a study by having half of a group play a mentally challenging computer game for 90 minutes. The other half of the group were tasked with watching a pleasant 90-minute documentary, such as The History of Ferrari. At the end of these tasks, all participants were then asked to exercise on a stationary bicycle until they reached exhaustion. The participants who’d just watched television lasted, on average, 15.1 percent longer than those who’d played the computer game. The groups were physiologically similar to each other, so the results suggested that it was the mental fatigue of the complex computer game that caused the participants who’d played it to become exhausted sooner. This study also displays proof for the theory that says that perceived effort is a significant factor in endurance. People have been studying perceived effort since the 1960s, when Swedish psychologist, Gunnar Borg began his study and measure of this quality. Borg came up with a scale that went from six to twenty: six being the least perceived effort a person can display, and twenty being the most. What Borg found forced a complete reconsideration of what science understood of endurance at the time. Up until this point the body was treated like any other machine, meaning that it would continue functioning as long as the mechanics (in this case, the muscles) were operational. From this mechanistic view, exhaustion can only come from physical effort. Marcora’s model took Borg’s findings a step further: he states that an athlete’s total exhaustion is the combination of both muscle fatigue, which creates the initial feeling of mounting effort, and the person having reached their maximum threshold of perceived effort. The point where these two things intersect is where all effort must cease for that person. It makes a big difference to consider perceived effort, since it has to do with a lot of different mental factors, such as how motivated a person is and any subliminal messages they may be picking up on.

Endure Key Idea #4: Athletes have a higher-than-normal pain tolerance, which leads to better performance.

Veteran cyclist Jens Voigt has worn the Tour de France yellow jersey twice, symbolizing that he’d taken the lead in the famous race. However, he is also known for his love of physical suffering, which, as he puts it, is just a weakness to overcome. While this view might sound extreme, there are many athletes who would agree. It’s also important to note that it may just be an athlete’s willingness to suffer physically that leads to the fact that athletes simply have a higher pain threshold than the average person. One of the first studies of athletes’ perception of pain was conducted in 1981 by psychologist Karel Gijsbers, who compared the pain tolerance of elite swimmers to that of amateur swimmers. Dr. Gijsbers measured their pain by using a blood-pressure monitor to stop the blood circulation in the participant’s arm. While this was happening, the participants were told to clench and open their fist once per second. Gijsbers was able to mark their pain threshold as the moment when they first reported pain, the maximum tolerance being the instant they asked to stop. While the pain tolerance of all participants was similar, the elite swimmers could continue contracting fists for far longer than the amateur ones. On average, the hobbyists could make 89 fists while the athletes could make 132. Now the question is, why can athletes endure so much more pain? Subsequent studies by Dr. Gijsbers suggest that it is due to training. By testing athletes throughout their swim season, Gijsbers was able to find that overall, the pain tolerance was at its highest when their training was at its peak, which was during the month of June. This isn’t the only proof of this: a related study from Oxford Brookes University shows that increased pain tolerance is correlated with increased athletic performance. It was even evident that athletes who trained with short sections of high intensity, and therefore high pain, progressed more than those who trained for longer periods of less intensity. Therefore, the more pain tolerance an athlete endures during training, the more benefits they’ll experience in their performance. However, an ability to tolerate pain is only one factor of good athletic performance, as we’ll discover in the next book summary.

Endure Key Idea #5: Athletic performance greatly relies on oxygen intake.

All athletes can attest that a good coach is one of the best things for their performance, and if there’s one piece of advice that every coach will give, it’s to breathe, breathe, breathe. Breathing is essential to anyone’s athletic performance, as oxygen intake has a direct influence on an athlete’s abilities. During training, athletes can measure their maximum oxygen intake through what is known as VO2max, which stands for volumeoxygenmaximum. Basically, the more oxygen a person is able to take in, and therefore circulate through their body, the better they’ll perform – especially in endurance sports like marathon running. It wasn’t by chance that Norway’s Bjorn Daehlie not only won multiple cross-country skiing awards in the 1990s, but also held the record for the highest VO2max ever measured. Daehlie topped out at 96 milliliters of oxygen per kilogram of body mass per minute. The average human capacity is 35 ml/kg/min, so this is a massive, record breaking amount. Of course, VO2max isn’t the only indicator of athletic performance. Another Norwegian athlete, Oskar Svendsen, beat Daehlie’s record with a VO2max of 97.5 ml/kg/min. However, because Svendsen was a cyclist, he retired early after a spotty career. The ability to intake oxygen is also the reason why athletes perform better at lower altitudes. At lower elevations, there is simply more oxygen available. Canberra University in Australia is located at an elevation of 577 meters above sea level. According to the school’s own study, this elevation significantly reduced the VO2max levels, causing the school’s runners to produce slower run times. Conversely, when runners experience an oxygen-rich atmosphere, they’re more likely to beat their own personal best and set new world records. Scientist Yannis Pitsiladis came up with the idea to host a marathon at the Dead Sea, 400 meters below sea level. His theory is that holding the event at such a low elevation could be the solution to having a runner finally overcome the challenge of finishing the race in less than two hours.

Endure Key Idea #6: Endurance is also affected by a person’s core body temperature.

Heat stroke is one of the most dangerous risky situations that athletes can find themselves in. It has shown how deadly it really is to both professionals and amateurs alike. Avoiding heat stroke is a huge reason athletes pay close attention to the overall temperature of their bodies, also known as their core temperature. But there is another link between heat and athleticism, which is that core body temperature actually influences an athlete’s endurance. More specifically, an athlete’s core body temperature is a good indicator of how much more they’ll be able to endure. The link between temperature and performance was the basis for a 1999 study by Copenhagen University’s José Gonzalez-Alonso. He closely studied seven athletes who he told to exercise on a stationary bike until they reached a point of exhaustion. Prior to exercising in this way, the athletes bathed for 30 minutes in water that was either 36, 37, or 38 degrees Celsius. In the end, the cyclists with a 36-degree core temperature lasted twice as long as those with a 38-degree core temperature. Overall, the study showed that every participant called it quits when their core temperature reached between 40.0 and 40.3 degrees. This exact study had a great influence on the 2004 Olympics in Athens, during which, coaches used cooling basins before a competition to bring down their athlete’s core temperature. Since then, research in this area has questioned which area affects core temperature the most: the brain or the stomach? In the 2008 Olympics, certain athletes were drinking ice slushies before competing, adhering to the fact that melting ice in the stomach has been found to lower core temperature by as much as 0.7 degrees Celsius. Doing this also seemed to give athletes the ability to push their core temperature slightly higher before they reached a point of exhaustion – around one-third of a degree more. What is the reasoning behind this? It’s believed that when athletes compete after drinking the ice slushy, the body is the first part to warm up, but the whole system won’t actually reach exhaustion until the brain reaches that critical temperature. The data behind this, though, is still inconclusive. It’s very possible that the temperature sensors in the stomach are the main influencer for the brain when it comes to shutdown, and drinking the slushy delays this signal. At the time of writing, neither hypothesis has yet been confirmed.

Endure Key Idea #7: Another way to improve athletic performance is through mindfulness and lowering stress levels.

Based on evidence already stated, we know that the mind plays a bigger role in physical endurance than sports scientists believed in previous generations. However, in the East, the power of the mind has always been seen as the center of athletic performance, especially in sports such as martial arts. It’s only in recent years that Western cultures have begun looking to Eastern influence of mindfulness for insights into achieving higher levels of endurance. We normally define mindfulness as giving all of our attention to any given action, and we can credit its introduction to Western training programs to German neuroscientist Martin Paulus. Dr. Paulus was especially interested in the influence mindfulness might have on soldiers. Dr. Paulus brought into Western lexicon the mindfulness concept of Zen Buddhism, as taught by Jon Kabat-Zinn, who developed a structured eight-week program aimed to lower stress levels. His belief was that lowering stress would keep soldiers calmer during stressful situations. A 2016 study involved Dr. Paulus testing his results on soldiers near San Diego, California. The soldiers involved in this study had their brain activity monitored via an MRI machine. While the soldiers were in the MRI machine, the oxygen levels given to the soldiers were altered in different ways, at times making it difficult to breathe. The results of this showed that the soldiers who had not had mindfulness training were more likely to panic when their oxygen levels decreased, which then led to a peak of activity in the stress-related insular cortexregion of the brain. Then, after spending eight weeks in mindfulness training, the soldiers did not show stress during this situation and their insular cortex remained stable. Because of this, there is hope for soldiers to cope better with stressors in the field through cultivating mindfulness. On top of that, there is already plenty of proof that mindfulness is effective when it comes to reducing symptoms of post-traumatic stress disorder. Dr. Paulus has worked to develop a special mindfulness program tailored to athletes. This has an emphasis on embracing pain, concentration, and self-compassion. The results of these mindfulness programs haven’t yet been measured, but the US Olympic BMX Team have reported improvements in their performance since starting the program. Their racing times have improved, and the athletes have reported a feeling of deeper consciousness and connection to their bodies during activities. Summary Pt 8: The insular and motor cortices are the areas of the brain that are the closest related to endurance. Everyone’s experienced feeling exhausted. However, not many people are aware of what the precise process is which causes us to hit a certain point that leads to a full-body shutdown. For decades, scientists have been studying exhaustion as a purely physically response, however, neuropsychologist Kai Lutz was the first to think that exhaustion might be something that comes from within the brain. He found that the regions of the brain that first recognize exhaustion are the insular cortex and then the motor cortex. Dr. Lutz discovered this through using EEG scans, or electroencephalography, which is a technique that tracks the brain’s electrical wave patterns. He studied cyclists pedaling at high speeds until they hit the wall of exhaustion around the 40-minute mark. Dr. Lutz observed that shortly before the cyclists gave up, the insular cortex was activated. The insular cortex is located at the center of the cerebral cortex and the brain itself. Right after it is activated, it was clear that a signal was then sent to the motor cortex, which is in charge of muscle control, resulting in the athletes calling it quits soon afterward. Since these are the two areas that anticipate the collapse of muscles from exhaustion, it is fair to call these two cortices the brain’s endurance center. However, it still isn’t quite clear how much control we can have over these areas of the brain. Dr. Lutz has found that we might be able to control and suppress the sensitivity of the neurons in the insular cortex, which would allow you to delay the message to the motor cortex and therefore, the muscles. This was tested in 2015 by another neurophysiologist: Alexandre Okano of the University of Rio Grande. In Dr. Okano’s study, he hooked cyclists up to electrodes that would directly activate the insular cortex via transcranial direct-current stimulation. After 20 minutes of this stimulation, the cyclists improved their racing times by around 4 percent before reaching exhaustion. Another theory is that continually stimulating the neurons of the motor cortex would effectively block the signal from the insular cortex. This might sound like a promising theory, but it hasn’t yet been proven successful. The practice of transcranial direct-current stimulation is still in its rudimentary stages. Scientists studying this are thus far unable to deliver this stimulation with pinpoint accuracy. By targeting the motor cortex with this stimulation, other parts of the brain are affected, including the insular cortex. Nevertheless, it’s been shown through these studies that progress has been made toward understanding human endurance, although there is still a long way to go before we have complete control.

Extract of a Q&A with Alex Hutchinson in The Verge

Once, we believed that the body was a machine, and the secret to optimal performance came from the muscles, the lungs, the heart. Then, we were told that it’s all in our head, and we just need to push through the pain. The truth is that “the brain and the body are fundamentally intertwined,” writes Alex Hutchinson, a fitness journalist (with a doctorate in physics) who competed for the Canadian national team as a runner. To understand the limits of the human body, you have to consider them together.

In the eight years he worked on the book, he traveled to labs all over the world and spoke to hundreds of athletes and scientists about how the mind and body influence each other and the role that each plays in the “mystery of endurance.”

The book is about the limits of the human body and the role that the brain plays. In the first part, you trace the intellectual history of these attitudes toward endurance, from the notion that the body is just a machine to the “it’s all in the mind” saying we hear a lot today. Can you go over that with us?

Yes, though of course my attempt to trace the intellectual history streamlines and makes simpler things than they really were. In the 1920s, the Nobel Prize-winning physiologist A.V. Hill wrote all these ideas for Scientific American, talking about how the human body is just a machine, and if we could learn the parts and measure the outputs, we can really confidently predict the outer limits of human performance. And he introduced the concept of VO2 max[maximal oxygen consumption], which you hear a lot in exercise science. No one really thought VO2 max was the be-all and end-all, but the philosophical underpinning was that if we could know everything about how the body works, we could understand what the limits were.

That was the dominant 20th century paradigm. In the ‘90s, though, a guy named Tim Noakes gave some very controversial lectures saying, you got it all wrong, the brain is what determines human performance. I’d say the last 10 or 15 years, there’s been lots of talk about the role that the brain plays, and that’s where the interesting debates are now.

The caveat I’d add is that even A.V. Hill knew that the brain mattered, but this is how we’ve evolved from a focus on the muscles to a focus on the brain — to the point where we hear that it’s all in your head. But actually, all this time, there’s been a parallel stream saying “it’s all in your head,” and that’s positive psychology, which isn’t really within the realm of science. So now we’re looking at the scientific underpinnings of claims that sounded a little silly — like the idea that changing your internal monologue can really do something.

I think everyone can understand why and how the body limits us. What are some studies that stood out to you that showed how the mind does the same?

One of the most eye-opening experiments to me was done by Samuele Marcora using subliminal images. He had cyclists do a test to exhaustion, and on the screen in front of them, he flashed pictures of either smiling faces or frowning faces. These were flashed 16 milliseconds at a time. That’s like a tenth of the length of a blink, so the cyclists were totally unaware that there were any images. It wasn’t like a placebo effect or something to do with self-confidence. They weren’t even aware of this manipulation.

The ones who saw the smiling faces lasted 12 percent longer on the ride than with the frowning faces. These sorts of experiments are really controversial right now with the replication crisis, so I don’t want to overstate the significance. But if these results stand up, they’re a really nice demonstration of the complicated ways that the brain’s interpretation of the body signals is maybe more important than the body signals themselves.

Seeing smiles helps us create a sense of ease. You see someone smiling, it makes us feel more comfortable and somehow that bleeds into the idea that your panting breath and your aching legs aren’t quite as bad as they might otherwise seem.

What else interested you from talking to so many scientists?

Another line of research that I’ve found really interesting — but also a little bit worrying — is electrical brain stimulation, which basically amounts to taking a nine-volt battery, attaching a couple of wires to it, connecting to your head, and running a very weak current through your brain to change the excitability of the neurons. If you put the electrodes in the right place, you can enhance endurance.

It’s been around for three or four years, with conflicting results, though it seems to be getting more repeatable now. What seems to be happening is that you’re altering your perception of effort. You’re not changing your lactate levels or your heart rate, just changing how your brain interprets those signals.

So, for our readers who aren’t closely following the science, are there certain concepts and theories that are key to understanding how the brain might influence endurance?

There’s lots of debate about exactly how the brain controls endurance, but there are two key concepts that are dueling right now. One is that, fundamentally, your brain is just trying to protect you, and it does this by trying to anticipate what’s going to happen. So if you go running on a hot day, you go slower, not because your core temperature is at a dangerous zone, but because your brain is worried that it’s going to reach a dangerous zone and you’re going to overheat and cause damage. Fundamentally, all of these warnings and perceptions and feelings of discomfort are designed to save you from your own worst decision-making. And that requires your brain to be smart and anticipating the future. This comes out of Tim Noakes’ work, and he called this the theory of the brain as “central governor.”

The other main sort of tenet out there is from Samuele Marcora. He says, there’s no prediction of the future, there’s no really subconscious protective circuitry. Fundamentally, all endurance is is the balance between how hard it feels and how hard you’re willing to make it feel, between perceived effort and motivation. So everything that’s going on in your body — your core temperature, your oxygen levels dropping — all of that is important only insofar as it makes exercise feel harder to you, and at a certain point, it’ll reach the maximum you’re willing to tolerate and you’re willing to slow down or stop. That’s a conceptually simpler approach that doesn’t require any sort of anticipatory prediction of your future state. It’s just “this is harder than I’m willing to work.”

What surprised you the most?

One of the biggest surprises came when I was looking into limits of hydration and heat. Alberto Salazar, one of the greatest American marathoners, very famously almost died a few times after races. People always say it was because he didn’t drink enough, and I was looking back at debates in medical journals in the 1980s. After the 1982 Boston Marathon, the so-called “duel in the sun,” his body temperature was something like 88 degrees Fahrenheit [instead of our normal 98.6 degrees Fahrenheit]. Everyone had assumed he didn’t drink enough and he got heat stroke, but the link between hydration and heat stroke was different than expected when you look into the details of these famous collapses.

Generally, I came at this from the perspective of running, and that involved thinking broadly. In running, you breathe hard and you think that oxygen is a limiting factor, so I also looked into these free divers to see how long you can go without oxygen. The record for holding your breath is almost 12 minutes! From a physiological perspective, when I hold my breath I reach a point where I physically can’t anymore because my breathing muscles are contracting. It turns out that that’s not because I’m out of oxygen, it’s because my carbon dioxide levels are too high and are triggering a warning system in me. But these guys are able to ignore that warning system and just keep holding their breath until they’re literally out of oxygen.

To what extent do people’s bodies and genetic gifts give them an advantage? Take the free divers, for example. How much does it help that they probably have bigger lungs?

The lungs probably helped in some respect, but it’s not fundamentally the key limiting factor. If you want to be a world record-holder, you need to check a hundred different boxes. You need to have psychological and physiological and morphological characteristics. But think about it this way: I can hold my breath for two minutes, and he can hold it for 12, but I’m nowhere near my limit. My lung size makes no difference whatsoever until I’ve already learned to push my limits a lot more

Yes, there are physical differences for sure, and they are absolutely crucial. The strongest mind in the world is not going to win the Boston Marathon unless you have all the other physical characteristics. It’s like the nature-nurture question in the sense that it’s almost impossible to separate the role of nature and nurture. And similarly, you have a total kind of synergy between psychological and physiological and physical characteristics that go into defining your limits.

One of the phrases I’ve heard at conferences when people talk about great athletes is that there’s probably some degree of benign masochism that the people who love to go out and run 100 miles a week are not just physically capable but mentally capable of doing that. For whatever reason, their brains are wired in a way that they get more of a kick out of it than the rest of us. Whatever brain chemicals make you feel satisfied, we don’t all get them in the same way, some people are inherently more eager for new experience or novelty or risk.

Is there a way to quantify the effect of the brain versus the body in endurance?

To answer that question, you have to think about what population you are looking at. Let’s say I ask, how important is height in the NBA for in basketball success? If you take the general population, well height is almost everything. If you’re not well over six feet tall, your chances of making it to the NBA are almost zero.

But how important is height to scoring success in the NBA for players who’ve made it? It’s not better to be tall and height is essentially irrelevant at that point. If you want to know who’s gonna be good at a marathon and just talking about in the population of the United States, send everyone to an exercise lab and have them do a bunch of physiological tasks. Those tasks will tell you almost everything you need to know. It really is the human machine. It’s VO2 max, lactate threshold, the running economy. You’re going to pick with very, very high accuracy who’s going to be good and who’s not.

But if you go to the Olympics and you do the same physiological test, that’s going to tell you nothing about what’s going to win the race. Everyone has the physical tools, and it’s not everything.