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Book Review: The Sports Gene by David Epstein, and the Fascinating Science behind Athletic Performance

David Epstein, Senior Writer for Sports Illustrated, addresses questions about nature and nurture in the context of athletic success in his compelling new book, The Sports Gene.

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David Epstein's seminal contribution to sports and science.
David Epstein's seminal contribution to sports and science.

Pop science has taken a hit over the last few years, especially as journalists have attempted to make sense of subjects like neuroscience. The most high profile paragon turned pariah was Jonah Lehrer, who sabotaged himself by fabricating Bob Dylan quotes. However, for a lot of critics, it wasn't the plagiarism that was the real problem with Lehrer, but rather, his Gladwellian presentation of the complex scientific ideas he was writing about.

This is the dilemma for any science writer: making science digestible to the layman without being condescending (while sacrificing the complexity of the ideas in the process). Enter Sports Illustrated's David Epstein. In his fantastic new book, The Sports Gene, Epstein broaches a wide range of topics in a way that is at once fiercely literate, and intensely sympathetic.

The craft and class on display is owed, at least in part, to the sobering story of Epstein's former training partner and friend, Kevin Richards, who dropped dead during a February race at Evanston Township High School in 2000. The cause was a genetic disease known as Hypertrophic Cardiomyapothy; a single genetic alteration Epstein describes as "like a single typo in a string of letters vast enough to fill thirteen complete sets of the Enyclopaedia Britannica." And out of that typo, a tragic loss for the friends and family of Kevin Richards.

This experience set the stage for his curiosity about genetics, and out of the curiosity, broader questions about race and gender in sports, and how nature and nurture interact to influence athletic performance. While Epstein adheres to the story-study-lesson cycle of popular science writing, there's nothing formulaic about the book, nor is there a "lesson" to be packaged.

Right away Epstein takes aim at at these pop culture simplifications about athletic success and the "10,000" hour rule. In a chapter titled 'A Tale of Two Jumpers', Epstein unpacks the real meaning of K. Anders Ericsson famous "10,000-hour rule" study, emphasizing that complexity with a story about Stefan Holm; a Swedish high jumper who won gold in 2004 at Athens, and who explained his success as the result of Gladwell's book, "Outliers" and how he reached a 10,000-hour+ endzone. Now imagine his confusion when looking at the man who beat him in the 2007 World Championships in Japan; Donald Thomas, a 6'2 Bahamian high jumper, and former basketball player, who didn't even get into the sport he'd win gold in until only months prior.

Epstein is interested in the role "nature" plays in athletic performance, and there's a clear emphasis on human biology. What separates Epstein's book from most pop science books is that he isn't looking to boost ticket fees for his public speaking tour (though he may well have to consider this first world dilemma after more people open this book). He's not selling certainty; he's selling the complexity.

Some of this is by design. There's no way you can talk about race as a factor in athletic performance, and not tread lightly.

No subject better reflects that deftness than on the chapters on West Africans and their overrepresentation in world class sprinting.

The simple truth of Jamaican dominance doesn't require much explanation. Jamaica, a small island of less than 3 million citizens, produces the world's top sprinters. Usain Bolt, and Veronica Campbell-Brown hail from Trelawny Parish, Jamaica and even 100 meter record holders from Canada and the UK are Jamaicain expatriates (Ben Johnson being the most famous).

In selling the complexity, Epstein identifies the theories rather than the facts. Elaborating on Jamaican dominance in sprinting, there's a unique section in the book about how Jamaican sprinters from Trelawny can potentially trace their genetic roots from the fierce 17th century slaves known as the Maroons; slaves who earned their independence from the British ahead of emancipation schedule. But while DNA research isn't able to say much about the so called "Warrior-Slave Theory of Jamaican Sprinting" (Jamaicans are very genetically diverse), DNA research does reveal that Jamaicans are locked and loaded when it comes to ACTN3 (the so called "sprint" or 'speed gene').

Genes trigger the production of proteins to guide a cell's function in order to produce traits. ACTN3 triggers the production of a protein called Alpha-Actinin-3 that guides muscle cells to contract and fire rapidly. Having ACTN3 doesn't guarantee being athletic and explosive, but trends are revealing enough; like how having two disrupted copies of ACTN3 is incredibly rare among elite sprinters. Jamaicans, not surprisingly, are underrepresented when it comes to endurance sports.

This then leads to fascinating theory about what malaria and muscle fibers have in common (and what it has to do with ACTN3). According to Jamaican medical researcher Errol Morrison (with the help of the speechwriter to Jamaican prime minister Michael Manley, and friend, Patrick Cooper):

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 in more fast twitch muscle fibers, which are less dependent upon oxygen for energy production.

What's unique about Morrison's theory is that we already know a few things about malaria and West Africans. It's one of the most popular tales of human evolution: the stronger the presence of malaria in a given population, the more likely that population will produce the sickle-cell trait within its population.

This is because that as the blood cell assumes its unique, sickle shape due to decreased hemoglobin (and thus iron), the less effectively that pathogen can spread.

The 2nd part of Morrison and Cooper's theory has little evidence, leaving Epstein to recount a single UCLA study on mice, who when put on iron-deficient diets, suddenly "develop" fast twitch muscle fibers. Epstein makes it a point to emphasize that this is terrible evidence in the grand (and small) scheme of things, but that these are how theories are born.

But where Jamaicans may seems to emphasize nature's oversized role, they stand in stark contrast to Kenyans. While Kenyans dominate distance running, there is no one gene that seems to stand out (not that any gene does). Instead, their unique environment appears to be the overarching factor; "In one study (Yannis) Pitsiladis conducted with colleagues, 81% of 404 Kenyan professional runners had to run or walk a considerable distance to and from primary school as children. Kenyan kids who rely on their feet to get to and from school have 30% higher aerobic capacities on average than their peers."

This is in addition to altitude, where the Rift Valley offers an environment that increases red blood cell levels while fostering the narrow body type that is said to be good for endurance (explained in the book as "Allen's Rule"; a zoologist who noted that the extremities of animals get longer and more narrow the closer you get to the equator because greater surface area begets quicker heat release).

Throughout the book, you sense Epstein struggle with some of the provocative subject matter. But it's that struggle that makes the book so refreshing. There are no neatly packed conclusions, or accessible soundbites. This is a book about the complicated landscape of human biology, and how it works and doesn't work in the context of sports performance. As a quote attributed to Albert Einstein goes; "if you are out to describe the truth, leave elegance to the tailor." Epstein's book is written with the spirit of this quote through and through, but thankfully he hasn't left the elegance to the tailor.