WSJ - The Mental Tricks of Athletic Endurance

For the Slovenian cross-country skier Petra Majdič, the unlikely key to Olympic glory was misdiagnosis. While warming up for her first race at the 2010 Winter Games in Vancouver, Ms. Majdič skidded off an icy corner and fell more than 10 feet into a rocky creek bed. She dragged herself to an on-site medical tent for an ultrasound. “I don’t know,” the doctor said, “but it looks like everything is OK.”

Sure, she was in excruciating pain that made her shriek every time she exhaled. But the pain, she believed, was just in her head. As long as nothing was broken, her decision was clear. “Can I go?” she asked. The doctor said yes.

Later that evening, after gritting her teeth through a qualifying race, a quarterfinal, a semifinal and a final where she fought to an improbable bronze medal in the classic sprint, she finally went to the hospital—where she was diagnosed, correctly this time, with four broken ribs. The stabbing pain she’d felt during the semifinal? That was one of the broken ribs puncturing her lung, which then collapsed. She missed the rest of the Games and was in the hospital for nearly a week.

Such tales are a staple of Olympic lore, a stirring reminder of the heights to which athletes can rise with a medal on the line. In the coming weeks, as the world’s fleetest and toughest converge on South Korea for this year’s Winter Games, we will undoubtedly see more extraordinary feats of endurance. But how, exactly, do the athletes do it? Is it just a matter of physical prowess and training, or is there something else going on in these superhuman exertions?

Answers are starting to emerge from a remarkable new body of research on human performance, and the findings have lessons not just for Olympians but for everyone else, too. All of us, it turns out, are capable of pushing back the physical and psychological limits that we encounter at the gym, on the trails and in our sporting adventures. The feeling that you can go no further is just that—a feeling. And feelings can be changed.

Early studies of endurance focused, naturally, on the body. Physiologists pieced together an impressively detailed picture of the factors that—in theory—dictate our ultimate capacity. “Our bodies are machines whose energy expenditures may be closely measured,” wrote the pioneering (and Nobel Prize-winning) sports scientist A.V. Hill in 1926. As the mysteries of muscle contraction and metabolism were decoded, endurance began to seem like a question of plumbing—whose heart could deliver the most oxygen-rich blood through the widest vessels to the biggest muscles.

There was one big problem with this approach: It couldn’t predict who would win an athletic contest. No matter how accurately you measure physiological parameters like oxygen delivery, you’d be a fool to use that data to bet on the outcome of, say, a marathon. Clearly, something was missing from the “human machine” picture of athletic limits.

Hill and other early researchers soon realized that psychology must play a key role. In 1961, a pair of scientists at George Williams College in Chicago showed that they could boost the maximum strength of weightlifting volunteers by 7.4% if an experimenter sneaked up behind the subject and fired a .22-caliber starter’s pistol just before the lift. It was among the first (and most bizarre) attempts to demonstrate that the limits we perceive as physical and absolute are often negotiable and mediated by the brain.

The precise nature of the mind-muscle connection remains hotly disputed today, but most researchers accept the essential point: that the physical manifestations of fatigue —racing heart, elevated core temperature, a rising tide of metabolites like lactate in the blood—merely serve as sources of information for the brain, rather than direct limits on our ability to continue.

Starting in the late 1990s, the South African author and fitness researcher Tim Noakes advanced the view that our brains are wired for self-preservation. If you push hard enough to endanger your health—by overheating your core or compromising your brain’s oxygen supply, say—your brain will function as a protective “central governor,” automatically weakening the nerve signals driving your muscles. The feedback loop gives rise to the sensation of fatigue and signals you to slow down.

An alternate view proposed a decade later by Samuele Marcora, an exercise scientist at the University of Kent’s Endurance Research Group, posits that our limits are defined by the balance between motivation and perceived effort. We don’t stop because our fatigued muscles are incapable of continuing, in this view, but because the effort required to continue is greater than we’re willing to exert.
 
Whatever the mechanism, both camps agree that the subjective perception of effort is a sort of master controller—which means, in practical terms, that if you change your perception of a task’s difficulty, you can change your actual results.

There are plenty of examples of this phenomenon. In a 2014 experiment described in the journal Frontiers in Human Neuroscience, researchers led by Dr. Marcora showed cyclists images of smiling faces on a screen in imperceptible 16-millisecond flashes. The exposure boosted cycling performance by 12% over the level recorded with frowning faces projected in the same way. The sight of a smile didn’t lower the subjects’ heart rates or lactate levels, according to Dr. Marcora. Instead, it subtly altered how their brains interpreted those signals, evoking feelings of ease that bled into their perception of how hard they were pedaling.

Slovenia's Petra Majdič skied during the women's individual sprint classic cross-country at the Vancouver 2010 Winter Olympics despite having broken ribs—and won a bronze. Right, a team official helped her to the podium. Eliud Kipchoge, the Olympic marathon champion from Kenya, has sought to self administer the same effect. Mr. Kipchoge has come the closest to breaking the 2-hour barrier in a marathon, missing by just 26 seconds (in a race in Italy last year that doesn’t count in official records). He deliberately smiled broadly every mile or so during the final stretch. “When you smile and you’re happy,” he later explained to reporters, “you can trigger the mind to feel your legs.”

A technique called transcranial direct-current stimulation, or tDCS, which involves trickling a weak electric current between two electrodes on the scalp, also can alter the relationship between physical stress in the body and effort perceived by the brain. The current changes the excitability of affected neurons, making them slightly easier to trigger. This allows you to maintain a given level of exercise with weaker brain signals, which translates into a lower sense of effort. A study published this month in the journal Brain Stimulation showed a 23.5% increase in the time to exhaustion in cycling after 10 minutes of brain stimulation.

Such eye-popping outcomes have turned heads in the elite sports world. The U.S. Olympic ski and snowboard team reported a 13% boost in propulsive force and an 11% boost in jump smoothness when their ski jumpers tested headphones delivering tDCS effects. Brothers Bryan and Taylor Fletcher, who lead the U.S. Nordic combined (ski jumping and cross-country skiing) contingent heading to Pyeongchang, have been particularly eager adopters.

The technique is perfectly legal according to current Olympic and international sporting rules and would be difficult to regulate anyway, since its use is impossible to detect. Still, some scientists in the field have raised questions about the ethics of brain stimulation in athletes, calling for further research on its long-term safety.

Not everyone wants to wire up their brains for mild shocks, of course, but that’s hardly necessary to adjust your relationship with your apparent physical limits. There are simpler techniques. The crucial first step in all of them is to accept the idea that your perceived capacity for endurance doesn’t always correspond to any particular physiological reality.

For me, that happened when I was an aspiring collegiate distance runner more than 20 years ago. At a low-key 1,500-meter race in Quebec, the timekeeper, struggling to translate from French to English on the fly, called out wildly misleading midrace split times to me. Convinced that I was running faster than ever before without trying harder, I was unshackled from my pre-race expectations and self-limitations. I improved my previous best time by nine seconds in a four-minute race, an unprecedented leap for me, after being stuck at the same level for four years.

Such deceptions work in the lab, too. Cyclists in a heat chamber can maintain a faster pace if the thermometer is rigged to show a falsely low temperature, according to a 2012 study in the European Journal of Applied Physiology by researchers at the University of Bedfordshire. Olympic runners, cyclists and triathletes now commonly swish a sports drink in their mouths and then spit it out in the late stages of races, a tactic tested in a 2004 University of Birmingham study in the journal Medicine & Science in Sports & Exercise. It boosts performance by tricking the brain into thinking that fuel is on the way, even when the stomach can’t tolerate any more neon drinks. Olympic marathon champion Eliud Kipchoge,top center, celebrated after a race, May 6, 2017.

Former Boston Marathon champion Amby Burfoot once described the “absolute, nodoubt-in-the-world best running workout you can do” as a series of all-out mile repeats where, after you think you’re finished, your coach tells you to do one more at the same pace. The surprise? You can. Most of us don’t have sadistic coaches, or indeed any coach at all, but this general approach—setting a tough but achievable finish line for yourself, and then raising your sights once you reach it—is a powerful way of pushing beyond what seems initially feasible.

There are limits to the power of deception, though. In a French study published last year in Medicine & Science in Sports & Exercise, cyclists raced against a virtual-reality avatar of their previous best performance. When the avatar was secretly sped up by 2%, the cyclists managed to go 2% faster, but when the avatars accelerated by 5%, the benefits disappeared. The mind can deliver incremental gains, not quantum leaps.

Perhaps the most powerful and widely applicable technique for changing how your brain interprets incoming signals is to train yourself with motivational self-talk. Whether you’re conscious of it or not, you have an internal monologue running through your head during difficult tasks, and it has a measurable impact on how effortful you perceive those tasks to be. It is possible to channel that monologue in productive ways.

Many athletes consider such techniques a little hokey. My college track teammates and I laughed our way through the mandatory self-talk training we received from a well- meaning sports psychologist, figuring that if we honed our muscles and our maximum oxygen uptake sufficiently, we wouldn’t need to worry about such flimflammery.

That’s now one of my greatest competitive regrets, given the mounting evidence of self-talk’s physiological impact. A 2016 study by Stephen Cheung, an environmental physiologist and avid cyclocross competitor at Brock University in Canada, gave cyclists two weeks of self-talk training before an all-out ride in a heat chamber at 95 degrees Fahrenheit. Replacing negative thoughts like “I’m boiling” with motivational statements such as “Keep pushing, you’re doing well” boosted their time to exhaustion from eight minutes to over 11 minutes. Most tellingly, it allowed them to push their core temperatures half a degree higher, on average, before quitting.

In that slender half degree is the margin between perceived and actual limits—and, perhaps, between silver and gold in competition. Consider the closest (and wildest) finish at the last Winter Olympics in Sochi, a dead heat between Norway’s Emil Hegle Svendsen and France’s Martin Fourcade in the 15-kilometer biathlon. Both men notched identical times of 42 minutes, 29.1 seconds—but what’s most remarkable is the frantic sprint that preceded this finish. If limits were a simple reflection of spent muscle fibers and a maxed-out heart, you’d expect the final stretch of a long and grueling race to be the slowest. Instead, it’s often the fastest.

This isn’t simply a question of pacing errors or cat-and-mouse racing tactics. A 2006 analysis by South African scientist Ross Tucker analyzed the pacing patterns of every men’s world record in the 5,000- and 10,000-meter run in the modern era. Of the 66 races dating back the 1920s, the last kilometer was either the fastest or second-fastest in every case but one. The sight of the finish line—and the knowledge that you can soon stop—automatically reframes your brain’s interpretation of your body’s signals, and you discover that you’re not quite out of juice after all. None of this means that limits are “all in your head,” or that you can simply choose to ignore your brain’s diktats. But neither are those limits carved in stone. For the medal hopefuls in Pyeongchang, as for the rest of us, that’s a truly empowering idea. ‘The mind can deliver incremental gains, not quantum leaps. ’ Emil Hegle Svendsen of Norway and Martin Fourcade of France in the 15-kilometer biathlon atthe Sochi 2014 Winter Olympics.

What drove Petra Majdič onward during that long, painful day of competition in Vancouver? “I thought that Slovenians need some message—that it’s possible,” she told herself. “At the end of that path, the goal will be reachable. And you will have suffered to do it, but it doesn’t matter. You can do better.” —This essay is adapted from Mr. Hutchinson’s new book, “Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance,” which will be published by William Morrow on Feb. 6.