The Sports Gene: Inside the Science of Extraordinary Athletic Performance

by David Epstein

  Youth track is all the rage in Jamaica. Prior to Usain Bolt, professional track meets in Kingston played to empty stands, outdrawn even by the national championship for five- and six-year-olds. Puma stores around Kingston stock gear emblazoned with the emblems of schools that boast hallowed Champs histories, like Calabar High, named after a port city in Nigeria that was a final point of departure for slaves. The fever pitch of youth track gives rise to enthusiasts who want to help their local school succeed at Champs. Enthusiasts like Charles Fuller.

  Back in 1997, when he was an employee of the Alcan Jamaica aluminum company, Fuller was sick of watching the fastest local kids leave Manchester Parish for high school. It pained him to see neighborhood boys and girls help other schools defeat Manchester High at Champs. In an effort to hoist his local team back atop Champs, Fuller began to steer local runners to Manchester High. Runners like Sherone Simpson.

  In ’97, Fuller saw Simpson run in a local 100-meter race for twelve-year-olds. His mellow, baritone voice rumbles when he describes it. “She ran 12.2 seconds, hand-timed,” he says, his eyes widening. “And that was bare feet, in the grass!” Fuller marveled at Simpson’s lithe build. It reminded him of Grace Jackson, a Jamaican Olympian of the 1980s.

  But Simpson was an excellent student, and her primary school exam scores had earned her placement at Knox College, a premier academic school in Jamaica, and one without a track team. So Fuller intervened.

  He convinced Simpson’s parents, Audley and Vivienne, of their daughter’s potential on the track. Once they agreed, Fuller got Manchester principal Branford Gayle on board. Gayle contacted Knox College, and, after some prodding, Knox agreed to grant Simpson a transfer.

  For the first few years, she ran well at Champs, but Simpson was more focused on school. High school coaches in Jamaica are generally very conservative in training—most underclassmen don’t practice every day, and athletes don’t lift weights until at least fifteen or sixteen. High school practice, Simpson says, “was not intense.”

  But in 2003, her last year at Manchester, Simpson blossomed. She finished second in the 100 at Champs by a shoulder blade to future Olympic medalist Kerron Stewart. Scouts from American colleges, marked by shirts and hats with matching logos, prowl the stands at Champs. (Some scouts also stand out by virtue of the small number of white spectators in the stadium. When I visited Champs, a teenage boy approached me, uttering, “Excuse me, sir?” several times before I realized he meant me. “Do you have any scholarships available?” I was sorry to disappoint him.) Simpson was on the verge of accepting a full scholarship to the University of Texas–El Paso when one of her track-and-field guardian angels intervened, again.

  Nearby at UTech—where Errol Morrison is president—coach Stephen Francis was busily molding the MVP Track Club in an effort to give Jamaican athletes a venue to continue training after high school without leaving for the United States and the NCAA track system that Jamaican coaches feel over-races athletes. Manchester High’s principal Gayle called Simpson into his office: “‘You’ll do UTech for a year, and see how it is,’” Gayle recalls saying. “Then I let her cry, and wipe her eyes. And then she agreed.”

  In 2004, as a freshman at UTech, Simpson exploded on the international scene, finishing sixth in the finals of the 100-meters at the Athens Olympics. A week later, and just two weeks after her twentieth birthday, Simpson ran down U.S. superstar Marion Jones on the second leg of the 4×100-meter relay and became the youngest gold medalist in Jamaican history. Four years after that, in Beijing, Simpson tied for the 100-meters silver medal, behind UTech classmate Shelly-Ann Fraser-Pryce, and tied to the hundredth of a second with Kerron Stewart, who had nipped her at Champs five years earlier. Jamaica, 1-2-2 on the Olympic podium.

  •

  On a sweltering spring day, reclining on a concrete bench in view of the majestic Blue Mountains and beside the undersized grass track where the MVP Track Club trains, Simpson’s lips curl up toward her impossibly high cheekbones when she thinks back on her journey. “I remember it vividly, when Mr. Fuller saw me race the first time, and he came and told me I have a lot of potential,” she says. “It all started from there!”

  Simpson’s story is emblematic of the best of the Jamaican system: nearly every kid is made to sprint at some point in youth races (Simpson’s first wins came as a five-year-old in relays at the annual sports day held for Jamaican schoolkids), and adult track enthusiasts, like Fuller and Gayle, keep their eyes peeled for speedy youth and recruit them to good track high schools. There, they are developed very slowly, but get big-race experience at Champs, where they earn adoration and scholarships by performing well. Or, for the best of the best, a shoe company endorsement and membership in a pro club.

  The Jamaican sprint system resembles football in the United States, replete with its own shady boosters. (Several high school coaches at Champs told me that they are now banned from giving refrigerators to parents in an effort to recruit their children.) This island-wide, sprint-talent-spotting-and-capture system has paid off in Olympic gold for Jamaica. None other than Usain Bolt pined to be a cricket star in his youth (his second choice was soccer) until he started blowing away his peers in sprints on sports day and was pushed into track and field as a fourteen-year-old—and even then was renowned for ditching practice—ultimately setting Champs records in the 200 and 400 in 2003. Yohan Blake, Bolt’s training partner who finished second to him in the 100 and 200 at the 2012 London Olympics, also wanted to be a cricketer, but was identified as a sprinter during sports day at age twelve. Even top American sprinters often come via the Jamaican talent-spotting system. Sanya Richards-Ross, an American who won gold in the 400-meters in London, lived in Jamaica until she was twelve and was plucked by a primary school track coach when, at seven years old, she outstripped older girls in races on sports day. “The coach said, ‘Yep, you’re coming out for the track team,’” Richards-Ross says.

  Physiology findings indicate that endurance training can enhance the ability of fast-twitch muscle fibers to resist fatigue, but that sprint training does not increase the speed at which slow-twitch fibers contract. So being endowed with a large proportion of fast-twitch fibers is essential for an elite sprinter. Or, in the dogma of football coaches: “You can’t teach speed.” This is an exaggeration, as speed—and certainly the ability to sustain speed—can be improved. But recall the Netherlands’ Groningen soccer talent studies. No matter the training, the slow kids never catch up to the fast kids in sprint speed. And the words of Justin Durandt, manager of the Discovery High Performance Centre at the Sports Science Institute of South Africa: “We’ve tested over ten thousand boys, and I’ve never seen a boy who was slow become fast.” Slow kids never make fast adults. So keeping the swiftest kids in the sprint pipeline is paramount. And in what country other than Jamaica could a boy with blinding speed and who stands 6'4" at the age of fifteen, as Bolt did, end up anywhere but on the basketball or volleyball court or the football field? If he’s born in the United States, Bolt is no doubt ushered toward the path of towering speedsters like Randy Moss (6'4") and Calvin Johnson (6'5"), both large, fast NFL wide receivers who made many millions of dollars. (Johnson’s size and speed helped him land a $132 million contract in 2012.)

  The sprint results at Champs are actually comparable to those at state championship meets in big sprinting states, like Texas, and the Champs atmosphere has its fervor in common with Texas high school football. But scores of America’s would-be Olympic sprinters land instead in sports that are more popular in the United States, like basketball and football. (A Jamaican sportswriter I met at Champs was concerned that the rising popularity of basketball on the island could siphon off track talent.)

  Trindon Holliday, an NFL wide receiver, was such an outstanding sprinter at Louisiana State University that he beat Florida State’s Walter Dix—who would take bronze behind Bolt in Beijing—in the 100-meters at the 2007 U.S. national championships, but su
bsequently gave up his spot on the U.S. world championship team so that he wouldn’t miss a day of preseason practice for LSU football. Xavier Carter, who was at LSU at the same time as Holliday, chose to go pro as a sprinter only after failing to make an impact as a wide receiver in two years with the football team. In Jamaica, a key to world sprint domination is keeping the best sprinters on the track.

  It is the island-wide talent-spotting system—in which every kid is made to try sprinting at some point—that Pitsiladis credits with Jamaican sprint success. Not to say that genes don’t matter. “You absolutely must choose your parents correctly to be a world record holder,” he says, rhetorically. “But Jamaica has thousands and thousands sprinting, and you get the best coming through. That’s what accounts for this phenomenon. If you had this in any other country, you would see exactly the same thing.”

  When a Scottish publication solicited Pitsiladis’s advice for aspiring United Kingdom athletes, he responded: “Go into sprinting. Don’t worry because you’re white. It’s got nothing to do with the color of your skin.”

  His friend and colleague Errol Morrison would heartily disagree.

  11

  Malaria and Muscle Fibers

  Compared with Europeans, Jamaicans have longer legs relative to body height, and more narrow hips. This, Morrison says, is inarguable.

  That Jamaicans would have a more linear build than Europeans is no surprise, nor is it specific to Jamaicans. As Allen’s rule of body proportions dictates, men and women with recent ancestry from low latitudes and warm climates generally have proportionally long limbs. Another ecogeographic principle, known as Bergmann’s rule—named for nineteenth-century biologist Carl Bergmann—indicates that humans with recent low latitude ancestry will also tend to be more narrow, with slimmer pelvic bones. Both long legs and narrow hips are advantageous for running and jumping. All other factors being equal, maximum running speed scales with the square root of leg length. But the theory of western African sprint dominance that Morrison coauthored is a thesis entirely apart from these anatomical concerns.

  In 2006, Morrison, with Patrick Cooper, proposed in the West Indian Medical Journal that rampant malaria along the west coast of Africa, from where slaves were taken, led to specific genetic and metabolic alterations beneficial for sprint and power sports. The hypothesis: that malaria in western Africa forced the proliferation of genes that protect against it, and that those genes, which reduce an individual’s ability to make energy aerobically, led to a shift to more fast-twitch muscle fibers, which are less dependent upon oxygen for energy production. Morrison helped with the biology details, but the fundamental idea originally came from Cooper, a writer and childhood friend of Morrison’s.

  Cooper was a polymath who had professional success in jobs ranging from music recording to writing speeches for Norman Manley, an architect of Jamaica’s independence, and then for his son, Prime Minister Michael Manley. Early in his career, Cooper had been a reporter for The Gleaner, Jamaica’s largest newspaper. Working at The Gleaner’s sports desk, he first surmised that white athletes had historically dominated sprint and power sports only by systematically excluding or dodging black athletes, like boxing champion Jack Johnson. In later writing, Cooper meticulously documented the fact that athletes with western African heritage become highly overrepresented in sprint and power sports almost immediately once they are allowed a fraction of their white counterparts’ access to sports. Cooper highlighted trends that continue today: At every Olympics after the U.S. boycott of 1980, every single finalist in the men’s Olympic 100-meters, despite homelands that span from Canada to the Netherlands, Portugal, and Nigeria, has his recent ancestry in sub-Saharan West Africa. (The same has been true for women at the last two Olympics, and all but one female winner since the U.S.-boycotted 1980 Games has been of recent western African descent.) And there has not been a white NFL player at cornerback, football’s speediest position, in more than a decade.*

  As a speechwriter during Michael Manley’s combative 1976 reelection campaign, Cooper and his family were under constant threat. Cooper stopped sitting with his back to windows, and when his wife, Juin, was held up at gunpoint, he moved the family away from Jamaica, for good. Living in Houston in the late 1980s, Cooper haunted the library, stalking historical and biological explanations for the dominance of black athletes in sprint sports. Cooper read voraciously from scientific publications in biology, medicine, anthropology, and history in a manner that few ever did prior to the advent of electronic databases that sift scholarly journals with a keystroke.

  Cooper found the famous body types study of 1968 Olympians, and he latched on to a curious side note recorded by the scientists. The researchers had been surprised to find that “a sizeable number of Negroid Olympic athletes manifested the sickle-cell trait.” That is, some black Olympians had, in one of two copies of the gene that codes for hemoglobin—the oxygen-carrying molecule in red blood cells—a mutation that causes round red blood cells to curl up in a sickle shape in the absence of oxygen, potentially impairing blood flow through the body during vigorous exercise. The gene variant that causes sickle-cell trait is found most often in people with recent sub-Saharan ancestry in west or central Africa, and scientists had previously believed that the high altitude of the 1968 Mexico City Olympics would prevent athletes with sickle-cell trait from performing well. “Sickle-cell was supposed to be a deterrent,” Morrison says. But it made no difference at the Olympics in events of short duration, like sprints and jumps.

  In the decades since, epidemiological studies have found that athletes with sickle-cell trait (they have one copy of the mutant gene and are known as “sickle-cell carriers”) are indeed underrepresented in athletic endeavors that require aerobic endurance. In competitive running, sickle-cell carriers all but disappear in events longer than 800 meters. They are genetically disadvantaged for long-distance sports. In a small number of sickle-cell carriers, blood flow is inhibited to such a degree as to become deadly if they work out too hard for too long. Since 2000, the sudden deaths of nine college football players—all of them black and in Division I—during training have been tied to sickle-cell trait, and the NCAA now requires screening for the gene variant that causes it. (According to a panel at the 2012 Big East Conference Sports Medicine Society, white college athletes, on the advice of a team doctor, will often sign a waiver to forgo the testing, given the unlikelihood that they carry the sickle-cell gene variant.)

  In 1975, the year after the Mexico City Olympics data was published, another study appeared that Cooper would dissect two decades later, this one showing naturally low hemoglobin levels in African Americans. The work was published in the Journal of the National Medical Association, run by the Maryland-based National Medical Association, which promotes the interests of physicians and patients of recent African descent. Using data from nearly 30,000 people in ten different states, with ages ranging from the first year to the ninth decade, it reported that African Americans have lower hemoglobin levels at every stage of life than white Americans, even when socioeconomic status and diet are matched. (Errol Morrison’s wife, Fay Whitbourne, formerly head of Jamaica’s National Public Health Laboratory Services, says that hemoglobin levels among Jamaicans are in line with those of African Americans.) Numerous studies, as well as population data from the U.S. National Center for Health Statistics, have replicated this result in the years since, including in athletes. In a colossal 2010 study of 715,000 blood donors across America, researchers wrote that African Americans exhibit a “lower genetic set point for hemoglobin,” regardless of environmental factors like nutrition.* Like sickle-cell trait, genetically low hemoglobin—all else being equal—is a genetic disadvantage for endurance sports. Runners of recent western African descent are very much underrepresented at high levels of distance running. (The Jamaican record in the 10K would not even have qualified for the 2012 Olympics)

  The authors of the Journal of the National Medical A
ssociation paper wrote that lower hemoglobin levels raise the possibility that African Americans employ more of some alternate energy pathway to compensate for a relative lack of oxygen-carrying hemoglobin. Two years later, in the same journal, another group of scientists insisted: “some compensatory mechanism must exist to counteract this relative deficiency in hemoglobin, since a significant difference has even been demonstrated in healthy athletes.” Cooper set out to find that compensatory mechanism.

  His tireless perusal of medical journals took on greater urgency in 1996, when he was diagnosed with terminal prostate cancer. Cooper and Juin moved to New York City in 2000 so that Cooper could spend every day at the New York Public Library. “My office,” he called it. Weekend trips to Baltimore to visit his daughter doubled as visits to the University of Maryland library.

  And then Cooper found just the potential “compensatory mechanism” he was looking for, in a 1986 study from Laval University in Quebec published in the Journal of Applied Physiology and coauthored by Claude Bouchard, who would go on to become the most influential figure in the field of exercise genetics, and the leader of the HERITAGE Family Study that documented aerobic trainability differences among families. Bouchard and colleagues took muscle samples from the thighs of two dozen sedentary Laval students, primarily from countries in western Africa, as well as from two dozen sedentary white students, who were identical to the African students in age, height, and weight. The researchers reported that a higher proportion of muscle in the African students was composed of fast-twitch muscle fibers, and a lower proportion was slow-twitch muscle fibers compared with the white students. The African students also had significantly higher activity in the metabolic pathways that rely less on oxygen to create energy and that are engaged during an all-out sprint. The scientists concluded that, relative to the white students, the students from western Africa “are, in terms of skeletal muscle characteristics, well endowed for sport events of short duration.”