by Lars Leetaru

North: Finding My Way While Running the Appalachian Trail by Scott Jurek Little, Brown Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance by Alex Hutchinson William Morrow The Pursuit of Endurance: Harnessing the Record-Breaking Power of Strength and Resilience by Jennifer Pharr Davis Viking

Of all the things that could have broken Scott Jurek on a 2,189-mile run, it was a small tree root that crushed his spirit. He was 38 days into an attempt to beat the speed record for completing the full length of the Appalachian Trail, the mountainous hiking path that snakes along America’s East Coast, from northern Georgia to the top of Mount Katahdin, in Maine. Jurek, one of the greatest ultramarathoners of all times, was in trouble. After battling through a succession of leg injuries, then slogging through Vermont’s wettest June in centuries, he had to make up ground over a particularly merciless stretch of the trail, New Hampshire’s White Mountains. Delirious from just two hours of sleep following 26 straight hours of hiking, he was stumbling along the trail when he encountered the root in his path.

“As I saw it coming, I didn’t know what to do,” Jurek recalls in his new memoir, North: Finding My Way While Running the Appalachian Trail, co-written with his wife, Jenny. “Was I supposed to step around it or over it? I just couldn’t remember.” So he hit it and toppled. “I’d forgotten how to raise my legs,” he writes. “How to run like a sane person.”

Jurek’s victories in punishing 100-mile races since the late 1990s—plus a starring role in the writer Christopher McDougall’s best seller, Born to Run—have made him a distance-running celebrity. But tackling the Appalachian Trail forced him to dig deeper than he ever had before. Five weeks in, he was down more than a dozen pounds, and his ribs were visible. His eyes bulged, feral and unfocused. His body reeked of apple-cider vinegar as his sweat excreted excess ammonia. And his mind was beginning to crack. Late one night, he was mystified by the lights of a house he spotted on top of a mountain. A running partner had to explain that what he saw was the moon.

Jurek joins a tried-and-true literary tradition: the extreme athlete telling a harrowing tale of making it to the edge and back. From Edmund Hillary’s account of scaling Mount Everest to the long-distance swimmer Diana Nyad’s Find a Way, the genre offers athletes a chance to articulate how and why the toughest humans on the planet are capable of persevering when so many others would give up. The implicit promise is that readers will get a chance to learn something about how far the rest of us can push ourselves. And while we’re at it, perhaps we’ll glean the insight we really want: how far we should push ourselves. But what if extreme athletes are the worst sources of wisdom, and that is precisely what makes them fascinating?

Little, Brown

To hear Jurek tell it, forcing himself to the limit is purifying and transformational. “Though man’s soul finds solace in natural beauty, it is forged in the fire of pain,” he writes. But listen closely, and bodily transcendence is not exactly grist for motivational posters. Jurek’s pages are haunted by comrades who didn’t make it through the fire unscathed. He was joined for part of the trail by Aron Ralston, the hiker famous for amputating his own arm to free himself from a boulder. Jurek’s friend Dean Potter, a legendary climber and base jumper, died in a wing-suit accident days before Jurek began his trek. “I had known ultrarunners to finish races as their kidneys were shutting down and they were losing control of their bowels,” Jurek reports. He recalls a runner who fought through debilitating headaches to finish a 100-mile race and then died of a brain aneurysm.

Jurek and his kind are masters of walking themselves to the brink, but how they get there is only dimly understood. North, in fact, makes the case that a lack of curiosity on that score has been a secret of Jurek’s success. While he eagerly experiments with unconventional ways to improve his performance—veganism, Abraham Maslow’s theory of self-actualization, the samurai code—he has spent most of his career willfully ignoring the basic question of what possesses him to compete in such a punishing sport in the first place. “You rarely ask why when you win,” Jurek writes. For athletes at his level, endurance justifies itself: “We all kept going.”

Science backs up the notion that this unflinching drive forward is as essential as physical talent for competitors like Jurek, if not more so. Endurance is not all in your head, but as the journalist Alex Hutchinson explains in Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance, the brain plays a pivotal role in gauging exertion and ultimately dictating when it’s time to stop. “The psychology and physiology of endurance are inextricably linked,” Hutchinson writes. “Any task lasting longer than a dozen or so seconds requires decisions, whether conscious or unconscious, on how hard to push and when.” As things get tough, the mind constantly takes stock of physical reserves and negotiates with the body over just how long it can hold out.

This feedback loop is a relatively new model of endurance. Living creatures were long thought to be powered by some inscrutable, vital force. That belief gave way in the 20th century to what Hutchinson calls a “mechanistic—almost mathematical—view of human limits: Like a car with a brick on its gas pedal, you go until the tank runs out of gas or the radiator boils over, then you stop.” But more-recent research into the mind’s influence has made for much trickier analogies. All runners know that the racing experience is rarely linear. You might feel strong at the start, pained in the middle, then catch a second wind and charge to the finish. Some days you float; others you barely crawl. Physiologists broadly concur—despite plenty of heated debate over the specifics—that how your brain interprets your body’s signals sets the limit on the effort you can put in at any given moment. Tweak your mentality, and your sense of that limit can change.

William Morrow

Hutchinson tallies the conventional tools that any coach would recommend: positive thinking and visualization, good diet and hydration. He also delves into the more unsettling vanguard of expertise on breaking through the brain’s barriers. It includes “brain endurance training,” a weeks-long program of painfully boring computer tasks designed to help people fight off mental fatigue. Researchers, as well as an ever-growing scene of DIY enthusiasts, are trying transcranial direct-current stimulation (or “brain zapping”), which involves sticking dual electrodes to a subject’s skull in an effort to unlock the brain’s hidden reserves. (The practice is controversial, but some evidence indicates that it can enhance endurance and power.) In one series of experiments, scientists injected the powerful opioid fentanyl into the spines of cyclists so that they couldn’t register pain at all. The volunteers rode so hard that they couldn’t walk afterward—and they ended up pacing themselves so poorly that their times weren’t faster than usual.

Still, Hutchinson suggests, the single greatest impetus for stretching beyond your limits appears to be good old belief. No out-of-shape runner can crush a four-minute mile with motivation alone. But research shows that having an unshakable confidence in one’s ability and commitment reliably compels athletes to find that extra gear. “Training is the cake and belief is the icing,” Hutchinson reflects, “but sometimes that thin smear of frosting makes all the difference.” He offers a long list of studies that have sneakily goaded subjects into better performances:

Telling runners they look relaxed makes them burn measurably less energy to sustain the same pace. Giving rugby players a postgame debriefing that focuses on what they did right rather than what they did wrong has effects that continue to linger a full week later, when the positive-feedback group will have higher testosterone levels and perform better in the next game. Even doing a good deed—or simply imagining yourself doing a good deed—can enhance your endurance by reinforcing your sense of agency.

But beyond the boosts of trickery and experimental nudges, how is such belief instilled? How do you get the unrelenting sense of purpose that sustains, say, one of the world’s greatest ultra-marathoners? Not the way you might think: Avoiding introspection seems to be key. Hutchinson, a creditable runner himself (though his career never came close to matching Jurek’s), spends long passages puzzling over the mysteries of his own peak performances and dissecting his failures. Jurek, meanwhile, gives the impression that doubting his commitment hardly ever even occurred to him—until he hit the Appalachian Trail.

That challenge was different from any other he had attempted. His reflexive faith in glory was gone. This time he was motivated by an endurance athlete’s equivalent of a midlife crisis. In May 2015, Jurek was 41. He was a year past a promised retirement, and had been underperforming in races as he’d approached 40. His wife, Jenny, had just suffered a second miscarriage. Jurek felt buried under medical bills and a new mortgage, and he glimpsed salvation in running 84 consecutive marathons over “the gnarliest and oldest mountains in the world.”

Here was a chance to look inside himself and find direction. But beware self-scrutiny! Just seven days into navigating the rocky, often rain-soaked path, Jurek was already overcome by doubt. In agony, one quadriceps torn and the kneecap on his other leg severely inflamed, he was overtaken by the demon that success had so long shielded him from: “Why was I even out here in the first place?” he asked, hobbling beneath a canopy of oak branches. A mantra favored by one of the many veteran ultra-runners who accompanied Jurek for parts of the trail provided his answer: “This is who I am, and this is what I do.”

In other words, don’t ask why. Breaking through his own limits makes Scott Jurek Scott Jurek, for whom the mantra served to help reaffirm the value of his long-guarded myopia. Damp and miserable in North Carolina, he wrapped athletic tape around his battered legs and limped onward.

In her own more reflective way, Jennifer Pharr Davis—the very person whose record Jurek set out to break—ends up confirming the power of compulsive determination in her book The Pursuit of Endurance: Harnessing the Record-Breaking Power of Strength and Resilience. In 2011, she blitzed the Appalachian Trail in 46 days, 11 hours, and 20 minutes—an average of 47 miles a day. Though Davis’s ultrarunning credentials pale in comparison to Jurek’s, she’s no slouch: She’d already completed the trail twice and set the fastest time for women.

“Endurance isn’t a human trait; it is the human trait,” she writes, giving Jurek’s borrowed mantra more philosophical sweep. “We exist only as long as we persist.” Thanks to her gender, she had a sort of built-in Why? goading her. Male runners hold the world record in all commonly contested distances—from sprints to ultramarathons—by considerable margins. The best physical traits for taking on extreme distances on the scale of the Appalachian Trail, though, remain mysterious; men’s larger muscles and greater lung capacity may not hold up against women’s lighter frames and superior fat-burning abilities. As a sample of one, Davis couldn’t clinch the case, of course, but being a woman impelled her to prove herself on the trail.

Viking

Being a woman also gave her a reason to hang up her hiking shoes once the proof was in. “After the birth of my daughter, a part of me knew that I would never again be able to pursue an extended [trail record] with success,” she writes. Her body wasn’t the obstacle. You could say blinkered obsession was. “My transition to motherhood did not take a physical toll that would prevent me from setting a trail record, but emotionally I am no longer capable of putting my needs first for forty-six days.”

In detailing the loss of her competitive drive, Davis converges with Jurek, for whom extreme endurance is more a calling than a choice: Trail feats could no longer define her when something else did. Davis still glorifies endurance, and as she interviews many of the trail’s aging former record holders, she confesses to a certain envy of those who have never given up arduous regimens. “They have kept a part of themselves that I have let go,” she writes wistfully, a woman long wedded to tackling extreme physical challenges outdoors. But her admiration is tinged with an awareness that forging on, too, demands sacrifices. Most people find that there are many things well worth stopping for.

Not Jurek. After tripping over the root in New Hampshire, he picked himself up, charged forward in his delirium for another week, and defeated Davis’s time by a slim three hours: He finished in 46 days, 8 hours, and 7 minutes. Since then, two people have already beaten his record.