Usain Bolt Outruns Human NatureS

Usain Bolt, as winner of the 100 meter dash, receives the title "the world's fastest man." It carries a mystique unlike any other. Nobody cares about the world's best hammer thrower, or the world's best trampoliner. But running is different. Running speaks to something essential—no tools or equipment needed, nothing but a biped and a finish line. And yet, what Usain Bolt does might be the least primal, most unnatural thing of all.

Sports are a codified outgrowth of juvenile play, which itself is hardwired mimicry of survival skills. The young of any advanced species play harmless games that secretly train them to kill and avoid being killed, or to establish dominance. We humans are aware enough to embrace these skills for their own sake, not for what they represent in our collective unconscious. We give them rules, and hand out prizes, and call them sports.

Still, it's tough to find a sport that doesn't have some analogue survival skill. Archery and javelin are obviously hunting. Equestrian is husbandry. Cycling, swimming, or races of any kind are pursuit. Our ball sports involve throwing projectiles, one of our earliest and most basic hunting methods. (In hockey and tennis, we utilize tools to hurl the projectile farther and faster, making those sports, perhaps, more evolved.) Even a purely intellectual pursuit like chess is about weighing risk and reward.

These are humanity's most valuable skills, but they're not exclusive to us. In an alternate universe where felids out-evolved hominids, perhaps cheetahs fondly celebrate the first sub-minute mile. Among other species, other skills would be celebrated with sporting analogues. In the Cetacean Olympics, the signature events are spouting height and breath-holding. At the Chameleon Olympics, tongue flicks are ranked by speed and by distance, and camouflage speed is measured to the millisecond. Us humans? We throw, and we fight, and we run.

Our sport analogues for hunting and fighting are necessarily circumscribed, but running is pure. When Usain Bolt runs for recreation, in a specially designed shoe on a track of synthetic turf, it is physiologically descended from some stocky hominid sprinting barefoot across the veldt, sustenance ahead or death at his back. The same muscles adduct and abduct, the same ligaments stretch, the same stresses are placed on the same parts of the skeletal system. The same electrical pulses pump the same heart, sending out the same oxygen-rich blood to the same starved musculature. The same shocks on the foot are transmitted and damped and distributed the same way, all the while the same inner ear keeps the whole system in balance.

We are built to run. The human foot is wider, with smaller toes than those of our immediate ancestors. The second we came down from the trees, we began losing our opposable toes, because the foot no longer needed to grasp—it needed to support. (Usain Bolt is better designed for this than most of us, with his size 14 shoe.) The calcaneus is an enlarged fusion of two separate bones in our heels, an adaptation that offers unmatched shock absorption and spring. It is attached to our Achilles tendon, which is absent in other great apes, but crucial in us. It can support nearly four times our body weight while walking, and double that while running. The energy stored in the Achilles reduces the cost of running by as much as 80 percent. (When Bolt suffered his second-ever 100m loss in 2010, he was recovering from an Achilles injury.) Our legs are longer than those of our ape cousins (and Bolt, at 6'5" has legs longer than his competition), our knees are larger, and we stride with them directly underneath us for increased speed and balance.

But there are different types of running, and it appears for all the world that we humans are specifically designed for distance and endurance. We are, despite our bipedal advantages, remarkably poor sprinters, especially compared with the quadrupeds that our ancestors hunted and were hunted by. Over short distances, we are doomed and hungry.

Give us enough time, and there's nothing on earth we can't run down. This is persistence hunting, and it's still practiced today. In the heat of the Kalahari desert, hunters select a kudu, and just go after it. It will bolt, and initially escape capture. But pursued a moderate run pace—something akin to a marathon runner's stride—the animal can't stay ahead. It must stop to rest, and denied the opportunity, simply keels over with exhaustion, and is speared. The hunters don't need to rest; humans are endowed with an unmatched ability to cool down. Our sparse body hair and numerous sweat glands are our true evolutionary accomplishment. We can even outrace a horse over a long enough distance.

A 2004 study took a group of sprinters and a group of distance runners, and monitored them in two runs, one with a controlled speed, the other at maximum exertion. In the brisk jog, both groups naturally used the most energy-efficient gait. In the sprint, only the sprinters found an efficient stride; the distance runners' strides were demonstrably inefficient. The authors' conclusion was that distance running is an innate ability, while sprinting is learned and unnatural.

Whence Bolt? The answer may lie in his quadriceps. Being designed for distance means our legs are largely composed of slow-twitch muscle fibers, capillary-rich and perfect for sustained aerobic exercise. But the quads, the single strongest muscle group in the human body, which can generate 100 watts in short bursts, are different. They contain a variable proportion of fast-twitch muscle, designed for short and intense bursts. For most of us, the ratio is about 50-50. In a select few humans—including, presumably, Bolt—the quad can comprise up to 90 percent fast-twitch muscle. This ratio is randomly distributed across the population, but it is hereditary. Usain Bolt was made to sprint, while the rest of us are born to jog.

If distance running is innate, sprinting is the product of random mutation and a fanatical training regimen. Bolt is the best in the world at a skill that's wholly impractical in a state of nature. He ought not exist. Yet he does, and is celebrated for it far beyond, say, marathon record holder Patrick Makau. Makau is merely the apogee of tens of thousands of years of adaptation. Bolt can't outrun a big meaty gazelle, but he's speeding past evolution.