“You get leafy greens in your body first thing in the morning and you’ll lose a lot of weight,” she urged me. Because a monster salad is loaded with nutrient-rich carbs and low in fat, I could stuff myself and not feel hungry—or queasy—when it came time to work out. Plus, greens are packed with water, so they’re great for rehydrating after a night’s sleep. And what better way to down your five vegetables a day than forking them all down at once?
So the next morning, I gave it a stab. I wandered around the kitchen with a mixing bowl, throwing in my daughter’s half-eaten apple, some kidney beans of questionable vintage, a bunch of raw spinach, and a ton of broccoli, which I chopped into splinters, hoping to make it more like coleslaw. Dr. Ruth fancies up her salads with blackstrap molasses, but I figured I’d earned the extra fat and sugar, so I went upscale, dousing mine with gourmet poppy-seed dressing.
After two bites, I was a convert. A breakfast salad, I was happy to find, is also a sweet-topping delivery system, just like pancakes and syrup. It’s far more refreshing than frozen waffles, and, best of all, I could cram myself till my eyes were green and still shoot out the door for a workout an hour later.
“The Tarahumara aren’t great runners,” Eric messaged me as we began my second month of those workouts. “They’re great athletes, and those two things are very different.” Runners are assembly-line workers; they become good at one thing—moving straight ahead at a steady speed—and repeat that motion until overuse fritzes out the machinery. Athletes are Tarzans. Tarzan swims and wrestles and jumps and swings on vines. He’s strong and explosive. You never know what Tarzan will do next, which is why he never gets hurt.
“Your body needs to be shocked to become resilient,” Eric explained. Follow the same daily routine, and your musculoskeletal system quickly figures out how to adapt and go on autopilot. But surprise it with new challenges—leap over a creek, commando-crawl under a log, sprint till your lungs are bursting—and scores of nerves and ancillary muscles are suddenly electrified into action.
For the Tarahumara, that’s just daily life. The Tarahumara step into the unknown every time they leave the cave, because they never know how fast they’ll have to sprint after a rabbit, how much firewood they’ll have to haul home, how tricky the climbing will be during a winter storm. The first challenge they face as kids is surviving on the edge of a cliff; their first and lifelong way to play is the ball game, which is nothing if not an exercise in uncertainty. You can’t drive a wooden ball over a jumble of rocks unless you’re ready to lunge, lope, backpedal, sprint, and leap in and out of ditches.
Before the Tarahumara run long, they get strong. And if I wanted to stay healthy, Eric warned me, I’d better do likewise. So instead of stretching before a run, I got right to work. Lunges, pushups, jump squats, crunches; Eric had me powering through a half hour of raw strength drills every other day, with nearly all of them on a fitness ball to sharpen my balance and fire those supportive ancillary muscles. As soon as I finished, it was off to the hills. “There’s no sleepwalking your way up a hill,” Eric pointed out. Long climbs were an exercise in shock and awe, forcing me to focus on form and shift gears like a Tour de France cyclist. “Hills are speedwork in disguise,” Frank Shorter used to say.
That was the year my hometown in Pennsylvania got a heat flash for Christmas. On New Year’s Day, I pulled on shorts and a thermal top for a five-mile trail run, just an easy leg-stretcher on a rest day. I rambled through the woods for half an hour, then cut through a field of winter hay and headed for home. The warm sun and the aroma of sun-baked grass were so luxurious, I kept slowing down, dragging out that last half mile as long as I could.
When I got within one hundred yards of my house, I stopped, shucked my thermal shirt, and turned back for one last lap through the hay. I finished that one and started another, tossing my T-shirt aside as well. By lap four, my socks and running shoes were on the pile, my bare feet cushioned by dry grass and warm dirt. By lap six, I was fingering my waistband, but decided to keep the shorts out of consideration for my eighty-two-year-old neighbor. I’d finally recovered that feeling I’d had during my run with Caballo—the easy, light, smooth, fast sensation that I could outrun the sun and still be going by morning.
Like Caballo, the Tarahumara secret had begun working for me before I even understood it. Because I was eating lighter and hadn’t been laid up once by injury, I was able to run more; because I was running more, I was sleeping great, feeling relaxed, and watching my resting heart rate drop. My personality had even changed: The grouchiness and temper I’d considered part of my Irish-Italian DNA had ebbed so much that my wife remarked, “Hey if this comes from ultrarunning, I’ll tie your shoes for you.” I knew aerobic exercise was a powerful antidepressant, but I hadn’t realized it could be so profoundly mood stabilizing and—I hate to use the word—meditative. If you don’t have answers to your problems after a four-hour run, you ain’t getting them.
I kept waiting for all the old ghosts of the past to come roaring out—the screaming Achilles, the ripped hamstring, the plantar fasciitis. I started carrying my cell phone on the longer runs, convinced that any day now, I’d end up a limping mess by the side of the road. Whenever I felt a twinge, I ran through my diagnostics:
Back straight? Check.
Knees bent and driving forward? Check.
Heels flicking back? … There’s your problem. Once I made the adjustment, the hot spot always eased and disappeared. By the time Eric bumped me up to five-hour runs in the last month before the race, ghosts and cell phone were forgotten.
For the first time in my life, I was looking forward to superlong runs not with dread, but anticipation. How had Barefoot Ted put it? Like fish slipping back into water. Exactly. I felt like I was born to run.
And, according to three maverick scientists, I was.
*Nike’s policy of yanking best-selling shoes from the shelves every ten months has inspired some truly operatic bursts of profanity on running message boards. The Nike Pegasus, for instance, debuted in 1981, achieved its sleek, waffled apotheosis in ’83, and then—despite being the most popular running shoe of all time—was suddenly discontinued in ’98, only to reappear as a whole new beast in 2000. Why so much surgery? Not to improve the shoe, as a former Nike shoe designer who worked on the original Pegasus told me, but to improve revenue; Nike’s aim is to triple sales by enticing runners to buy two, three, five pairs at a time, stockpiling in case they never see their favorites again.
CHAPTER 28
TWENTY YEARS EARLIER, in a tiny basement lab, a young scientist stared into a corpse and saw his destiny staring back.
At that moment, David Carrier was an undergraduate at the University of Utah. He was puzzling over a rabbit carcass, trying to figure out what the deal was with those bony things right over the butt. The bony things bugged him, because they weren’t supposed to be there. David was the star student in Professor Dennis Bramble’s evolutionary biology class, and he knew exactly what he was supposed to see whenever he cut into a mammal’s abdomen. Those big belly muscles on the diaphragm? They need to anchor down on something strong, so they connect to the lumbar vertebra, just the way you’d lash a sail down to a boom. That’s how it is for every mammal from a whale to a wombat—but not, apparently, for this rabbit; instead of grabbing hold of something sturdy, its belly muscles were connected to these flimsy chicken-wing-looking things.
David pushed one with his finger. Cool; it compressed like a Slinky, then sprang back out. But why, in all mammaldom, would a jackrabbit need a spring-loaded belly?
“That made me start thinking about what they do when they run, the way they arch their backs with every galloping stride,” Carrier later told me. “When they push off with their hind legs, they extend the back, and as soon as they land on the front legs, the back bends dorsally.” Lots of mammals jackknife their bodies the same way, he mused. Even whales and dolphins move their tails up and down, while a shark slashes from side to side. “Think of an inchw
orming cheetah movement,” David says. “Classic example.”
Good; this was good. David was getting somewhere. Big cats and little rabbits run the same way, but one has Slinkies stuck to its diaphragm and one doesn’t. One is fast, but the other has to be faster, at least for a little while. And why? Simple economics: if mountain lions ran down all the rabbits, you’d have no more rabbits and, eventually, no more mountain lions. But jackrabbits are born with a big problem: unlike other running animals, they don’t have reserve artillery. They don’t have antlers or horns or hard-kicking hooves, and they don’t travel in the protection of herds. For rabbits, it’s all or nothing; either they dart their way to safety, or they’re cat food.
Okay, David thought, maybe the Slinkies have something to do with speed. So what makes you fast? David began ticking off components. Let’s see. You need an aerodynamic body. Awesome reflexes. Power-loaded haunches. High-volume capillaries. Fast-twitch muscle fiber. Small, nimble feet. Rubbery tendons that return elastic energy. Skinny muscles near the paws, beefy muscles near the joints …
Damn. It didn’t take David long to figure out he was heading toward a dead end. A lot of factors contribute to speed, and jackrabbits share most of them with their hunters. Instead of finding out how they were different, he was finding out how they were alike. So he tried a trick Dr. Bramble had taught him: when you can’t answer the question, flip it over. Forget what makes something go fast— what makes it slow down? After all, it didn’t just matter how fast a rabbit could go, but how fast it could keep going until it found a hole to dive down.
Now that one was easy: other than a lasso around the leg, the quickest way to bring a fast-moving mammal to a halt is by cutting off its wind. No more air equals no more speed; try sprinting while holding your breath sometime and see how far you get. Your muscles needs oxygen to burn calories and convert them into energy, so the better you are at exchanging gases—sucking in oxygen, blowing out carbon dioxide—the longer you can sustain your top speed. That’s why Tour de France cyclists keep getting caught with other people’s blood in their veins; those illicit transfusions pack in extra red-blood cells, which carry lots of extra oxygen to their muscles.
Wait a second … that meant that for a jackrabbit to stay one hop ahead of those snapping jaws, it would need a little more air than the big mammal on its tail. David had a vision of a Victorian flying machine, one of those wacky but plausible contraptions rigged with pistons and steam valves and endless mazes of wheezing levers. Levers! Those Slinkies were beginning to make sense. They had to be levers that turbocharged the rabbit’s lungs, pumping them in and out like a fireplace bellows.
David ran the numbers to see if his theory held up and … bingo! There it was, as elegant and niftily balanced as an Aesop’s fable: Jackrabbits can hit forty-five miles per hour, but due to the extra energy needed to operate the levers (among other things), they can only sustain it for a half mile. Cougars, coyotes, and foxes, on the other hand, can go a lot farther but top out at forty miles per. The Slinkies balance the game, giving the otherwise defenseless jackrabbits exactly forty-five seconds to either live or die. Seek shelter quickly and live long, young Thumper; or get cocky about your speed and be dead in less than a minute.
“You know,” he thought, “if you take away the levers, isn’t it the same engineering for every other mammal?” Maybe that’s why their diaphragms hooked on to the lumbar vertebra—not because the vertebra was sturdy and wouldn’t move, but because it was stretchy and would. Because it flexed!
“It seemed obvious that when the animal pushed off and extended its back, it wasn’t just for propulsion—it was also for respiration,” David says. He imagined an antelope racing for its life across a dusty savannah, and behind it, a streaking blur. He focused on the blur, froze it in place, then clicked it forward a frame at a time:
Click—as the cheetah stretches long for a stride, its rib cage is pulled back, sucking air into the lungs and …
Click—now the front legs whip back until front and rear paws are touching. The cheetah’s spine bends, squeezing the chest cavity and squishing the lungs empty of air and …
And there you had it—another Victorian breathing contraption, albeit with a little less turbo power.
David’s heart was racing. Air! Our bodies were all about getting air! Flip the equation, as Dr. Bramble had taught him, and you have this: getting air may have determined the way we got our bodies.
God, it was so simple—and so mind-blowing. Because if David was right, he’d just solved the greatest mystery in human evolution. No one had ever figured out why early humans had separated themselves from all creation by taking their knuckles off the ground and standing up. It was to breathe! To open their throats, swell out their chests, and suck in air better than any other creature on the planet.
But that was just the beginning. Because the better you are at breathing, David quickly realized, the better you are at—
“Running? You’re saying humans evolved to go running?”
Dr. Dennis Bramble listened with interest as David Carrier explained his theory. Then he casually took aim and blew it to smithereens. He tried to be gentle; David was a brilliant student with a truly original mind, but this time, Bramble suspected, he’d fallen victim to the most common mistake in science: the Handy Hammer Syndrome, in which the hammer in your hand makes everything look like a nail.
Dr. Bramble knew a little about David’s life outside the classroom, and was aware that on sunny spring afternoons, David loved to bolt from the labs and go trail-running in the Wasatch Mountains, which lap right up to the back of the University of Utah campus. Dr. Bramble was a runner himself, so he understood the attraction, but you had to be careful with stuff like that; a biologist’s biggest occupational hazard, second only to falling in love with your research assistants, was falling in love with your hobbies. You become your own test subject; you start seeing the world as a reflection of your own life, and your own life as a reference point for just about every phenomenon in the world.
“David,” Dr. Bramble began. “Species evolve according to what they’re good at, not what they’re bad at. And as runners, humans aren’t just bad—we’re awful.” You didn’t even need to get into the biology; you could just look at cars and motorcycles. Four wheels are faster than two, because as soon as you go upright, you lose thrust, stability, and aerodynamics. Now transfer that design to animals. A tiger is ten feet long and shaped like a cruise missile. It’s the drag racer of the jungle, while humans have to putter along with their skinny legs, tiny strides, and piss-poor wind resistance.
“Yeah, I get it,” David said. Once we came up off our knuckles, everything went to hell. We lost raw speed and upper-body power—
Good kid, Bramble thought. Learns quick.
But David wasn’t done. So why, David continued, would we give up strength and speed at the same time? That left us unable to run, unable to fight, unable to climb and hide in the tree canopy. We’d have been wiped out—unless we got something pretty amazing in exchange. Right?
That, Dr. Bramble had to admit, was a damn clever way to put the question. Cheetahs are fast but frail; they have to hunt by day to avoid nocturnal killers like lions and panthers, and they abandon their kills and run for cover when scrappy little thugs like hyenas show up. A gorilla, on the other hand, is strong enough to lift a four-thousand-pound SUV, but with a gorilla’s land speed of twenty miles per hour, that same SUV could run it over in first gear. And then we have humans, who are part cheetah, part gorilla—we’re slow and wimpy.
“So why would we evolve into a weaker creature, instead of a stronger one?” David persisted. “This was long before we could make weapons, so what was the genetic advantage?”
Dr. Bramble played the scenario out in his head. He imagined a tribe of primitive hominids, all squat, quick, and powerful, keeping their heads low for safety as they scrambled nimbly through the trees. One day, out pops a slow, skinny, sunken-chested son who’s bare
ly bigger than a woman and keeps making a tiger target out of himself by walking around in the open. He’s too frail to fight, too slow to run away, too weak to attract a mate who’ll bear him children. By all logic, he’s marked for extinction—yet somehow, this dweeb becomes the father of all mankind, while his stronger, swifter brothers disappear into oblivion.
That hypothetical account was actually a pretty accurate description of the Neanderthal Riddle. Most people think Neanderthals were our ancestors, but they were actually a parallel species (or subspecies, some say) that competed with Homo sapiens for survival. “Competed,” actually, is being kind; the Neanderthals had us beat any way you keep score. They were stronger, tougher, and probably smarter: they had burlier muscles, harder-to-break bones, better natural insulation against the cold, and, the fossil record suggests, a bigger brain. Neanderthals were fantastically gifted hunters and skilled weapon-makers, and may very well have acquired language before we did. They had a huge head start in the race for world domination; by the time the first Homo sapiens appeared in Europe, Neanderthals had already been cozily established there for nearly two hundred thousand years. If you had to choose between Neanderthals and Early Us in a Last Man Standing contest, you’d go Neanderthal all the way.
So—where are they?
Within ten thousand years of the arrival of Homo sapiens in Europe, the Neanderthals vanished. How it happened, no one knows. The only explanation is that some mysterious X Factor gave us—the weaker, dumber, skinnier creatures—a life-or-death edge over the Ice Age All-Stars. It wasn’t strength. It wasn’t weapons. It wasn’t intelligence.
Could it have been running ability? Dr. Bramble wondered. Is David really onto something?