20 Questions: David Epstein, Author of The Sports Gene

The Sports Gene covers all that we have learned in the decade since the sequencing of the human genome as to what genetic science can tell us about athleticism. As it turns out, some of the traits that appear innate–like the bullet-fast reactions of a Major League Baseball hitter–are learned, while others that seem to be entirely acts of will, like the compulsive drive to train, have important genetic components. Because geneticists have ventured into the bramble patches of gender and race, this book does as well. Through on-the-ground reporting from below the equator and above the Arctic Circle, The Sports Gene causes us to rethink the very nature of athleticism, and discusses how each athlete or exerciser can get the best out of his or her inimitable genome.

What specifically prompted you to write The Sports Gene?
I can trace the original motivation to four initial questions that came from my own experience as an athlete. First, I grew up outside of Chicago, in a town that had a mini-Jamaican diaspora in the 1970s and ’80s, and so many of my high school peers were track-enthusiast Jamaican immigrants, or sons and daughters of Jamaican immigrants. And some of them were really fast! My high school won 26 straight conference titles in track, and much of the success came on the backs of Jamaican runners. Jamaica is a nation of just 2.7 million people, so I started to wonder what the heck was going on over there. Were these runners importing some special speed gene from their tiny island? Then in college, I was a distance runner and so I was around a lot of Kenyan runners. And I began to learn that all of them came from one minority tribe in Kenya, the Kalenjin. So, again, I was wondering what was going on over there. Was there some secret training plan? Were there special genes? I was curious. At the same time, I noticed that my training group consisted of a group of guys who oftentimes did the same workouts, stride for stride, day after day, and yet we never crossed the line together. In some cases we got more different, even as we did the same training. How could that be, I wondered? Finally, as I write in chapter 15, one of my Jamaican training partners from high school dropped dead after a race, and I wanted to understand how a healthy state champion could just drop dead like that. So the book started with me investigating these questions, and then expanded from there.

What did you learn when researching for this book?

Well, it took me 110,000 words to answer that, which is why I had to write a book! But just to be very general, I learned that some skills that I thought were innate–like the bullet-fast reactions of Major League hitters–are learned, and others that I thought were entirely voluntary acts of will, like the compulsive drive to train, have important genetic components. I learned that the best genetic and physiological research in sports often contradicted my intuition about elite sports performance.

What was your biggest surprise?

Well, I was pretty darn surprised when I scored better than Albert Pujols on a test of visual reaction speed! Then I later learned–as I write in chapter one–that the reaction speeds of elite athletes are, on average, no different from teachers, doctors, lawyers, or journalists. I never would’ve guess that was the case, but the reason I was looking into it was because I couldn’t understand why–when I watched an exhibition softball game featuring Major League players–some of the best hitters in the world couldn’t even hit a foul ball off of Jennie Finch, the great softball pitcher.
What is the most persistent/pervasive myth you found in connection with athletes and genetics?
It’s hard to say, because there are so many. First of all, this idea that there could be a single “athlete” gene simply contradicts what we now know about the complexity of genetics, and I explain that in the book. Of course, I also explain the origins of the so-called “10,000-hour rule,” and how even the scientist who supposedly discovered it never felt that 10,000 hours was some magical number of practice hours required to attain expertise in sports. That said, to me, the most interesting bit of folklore was the story I was told in Jamaica, about how this group of warriors, known as the Maroons, who escaped enslavement under the British, intermarried and created the super strong and fast sprinters that we see coming out of Jamaica today. I visited the home of the Maroons and describe that in the book. I don’t want to give it away entirely, but the genetic evidence isn’t always consistent with their oral tradition.

How do you think the information in this book will affect the future of elite sports?

My sincere hope is that the book will lead to more interdisciplinary study of athletic expertise, and I believe that will happen, because I’ve received messages from scientists telling me this will be the case, and in some instances asking for data I used or to be connected to some of my sources! And I’m glad to facilitate that. I also think it’s quite clear now that the continued push for early specialization of youth athletes is either unnecessary or detrimental to ultimate achievement in most sports. Elites actually practice less at their eventual sport early on than do near-elites. Instead, they go through a sampling period where they find the sport that best fits their physiology, before focusing in. Steve Nash, for example, wanted to be a soccer player, and didn’t get his first basketball until age 13! Some kids who train too hard too early for sprinting hit what sports scientists call the “speed plateau,” where they get stuck in a certain running rhythm, and I write about that in the book. The bottom line is that the goal of exercise genetics is in line with the goal of medical genetics: personalized treatment. In 2007 the journal Science made as it’s breakthrough of the year “human genetic diversity…how truly different we are from one another.” It’s now quite clear that because we all have such different genomes, our optimal environment would also be unique, and I hope that comes through in the book. In fact, for the reporting of the book, I had some of my owns genes tested, and it turns that I happen to have an unremarkable aerobic baseline, but genes that predispose me to having a rapid response to endurance training, and that’s exactly what I saw in my own career as a national level runner. Exercise geneticists are showing as that an important kind of talent is not simply prowess that preexists the opportunity to train, but one athlete’s genetic setup that makes her profit from training more rapidly than her peers.
Was there any particular connection between athleticism and genetics that surprised you?
I knew full well that physical activity could impact our dopamine system, which is involved in pleasure and reward in the brain. I did not know that the reverse is true, that innate differences in our dopamine genes can influence the drive to be physically active. I guess intuitively that makes some sense, but I didn’t realize there was so much work done in the area of biological predisposition to physical activity. I write about that in chapter 14, where a scientists who studies it raises questions about how ADHD drugs might affect children who have a high drive to be physically active. Perhaps an important issue for future doctors to investigate!
What would you say is the most controversial topic in the book?
Race, race, race. It almost scared me out of writing the book. I was preparing my resume just in case I got drummed out of the profession. Scientists I interviewed sometimes told me they had data on ethnic differences, but would not publish them, for fear that their physiological work could somehow be construed as supporting the idea of innate intellectual differences, as if the two have anything to do with one another. These are professors with tenure, and they weren’t publishing, and there is no tenure in journalism, so I was concerned. But, as I write in the book, there are cases were ignoring ethnic differences in genes can lead to disastrous medical outcomes, so I felt compelled to write what I had learned.
How has the book been received by your scientific colleagues? By sports experts?
The reception has blown me away. I wouldn’t have made my mother buy 15 copies if I realized someone else would buy it! Even Malcolm Gladwell, of whom I’m quite critical at one point in the book, called it “a wonderful book” in one of his critiques. In any case, I don’t really have “scientific colleagues.” Though I was a science grad student at one point, now scientists are my friends and sources. The response has been remarkable. Just an hour ago I got an e-mail from Janet Starkes, a legend in the field of perceptual expertise in sports, saying that she didn’t think she could actually learn something from a popular book, but that she was proven wrong in this case. It’s hard to express how much that warmed my heart. I really do lose sleep over how the doctors and scientists I interview will feel about my work. The reception has been largely outstanding in the sports world as well. I’ve been contacted by loads of coaches and people who host podcasts and radio and TV shows about training. The only semi-antagonistic interview was one on the BBC with a writer who seems to feel that highlighting what is known about genetic talent will somehow imply that practice is not important. I disagree.

How do you think genetic doping will influence sports?

Traditional doping is so effective, and testing so easy to beat, I don’t know why anyone would skip over that yet. That said, the myostatin gene (chapter 6) and the EPOR gene (chapter 16), have certainly provided single gene targets that can cause an incredible boost in athleticism. As I wrote, some athletes are already looking to attempt gene therapy.

Are there sports/activities more directly influenced by genetics compared to others?

Well, there are certainly sports that are more constrained by genetics. Like the NBA. In my “Vitruvian NBA Player” chapter, I note that data from the NBA combine and CDC suggest that, if you know an American man between the ages of 20 and 40 who is at least seven feet tall, there’s a 17% chance he’s in the NBA right now. There are certainly sports where we know more about the important genes, but that’s not to say the effect is less in other sports, we may just not be far enough along with the research yet. But, as I quote Justin Durandt, manager of the Discovery High Performance Centre at the Sports Science Institute of South Africa, “I’ve never seen a boy who was slow become fast.” To be an elite sprinter, you simply have to be endowed with a high proportion of fast-twitch muscle fibers, and there are all sorts of innate traits that are important for other sports. The more competitive sports become, the greater number of people are ruled out either by not having the right nature or the right nurture.

What is the most important non-genetic factor(s) required to reach peak performance?

That’s an incredibly broad question, and the fact is there is no single answer. It’s not only different by sport, but also by athlete. That’s why, in my second chapter, I show two athletes arriving at the same skill level, one by a path of extreme training, and the other via extreme giftedness. There are not blanket answers. For something like hitting a 100 mph baseball, it is literally impossible for our biology without the specific kind of training that gives a hitter anticipatory skills. Are reflexes are not fast enough. Training quality is really important.

How has your research changed the way you approach your own fitness training?

Really, it just confirmed what I learned when I was a national level 800-meter runner, but it could’ve saved me time. I was a better runner at all distances on 35 miles a week of intervals tailored to my physiology than I had been on 85 miles a week of distance. I was even better at cross-country on the shorter regimen. If you aren’t looking to fit your training to your biology, then you are trying to get the best out of yourself. I don’t try cookie-cutter training plans, I find what works for me. Just as medical genetics showed that no two people respond to, say, a Tylenol quite the same because of differences in their version of a gene involved in acetaminophen metabolism, no two people respond to any particular training stimulus quite the same. So the trick is find that personalized training that is best for your genome. (Amazingly, work led by Claude Bouchard is finding that certain genes actually cause a small proportion of exercisers to go in the wrong direction on a number of health parameters. Clearly, it’s important to know who has those genes.) In any case, this is why I think it’s so appropriate that the American College of Sports Medicine adopted the motto: “Exercise is Medicine.” It really is, in every sense of the word, from the widespread benefits—for most people—to the individualized response.
What role do you see genetic testing playing in the future of sports? Should children be tested for the sports gene?
The gene I think more children should be tested for is the ApoE4 gene variant. We now know that it makes some kids more likely to be permanently brain damaged from playing football. As I write in chapter 15, the status quo in the medical community has been not to offer the test, because it’s merely statistical risk information, and one can’t change one’s DNA. I think that’s a mistake. A kid could change his or her environment by, say, not playing football. And I don’t think hiding from extra information is the right course with something like this. I think most people can handle the information. I was tested without reservation.

Has there been any reactions to your book that have surprised you? If so, what?

I’m surprised by the number of teachers who have emailed me questions related to using the book in their biology or exercise science classes. I definitely didn’t expect that.

Does the “10,000 hour rule” accurately represents the amount of training required to reach mastery of an activity? If not, why do you think the concept has proven to be so popular?

No, there is no rule. That came from a tiny set of violinists who were already so highly pre-screened for talent that they were in a world famous music academy. And then 10,000 hours was just the average number of retrospective recalled hours they had undertaken by age 20. AVERAGE. That is, it obscured the individual differences, which, as K. Anders Ericsson told me, were “certainly more than 500 hours.” There never was a rule, and Ericsson will be the first to tell you that. It’s probably popular because it’s catchy and seems to imply the greatest degree of personal freedom possible, as if genes are totally meaningless. The problem is, that’s not true.

How early in life should training began for a sport? Is there such a thing as too early and is it sport-specific?

In gymnastics, the average height of an elite female has shrunk from 5’3″ to 4’9″ in the last three decades. Those athletes have to start very early, or the window is gone. In almost all other sports, the most typical path of an elite is not early hyperspecialization, but rather a sampling period through about age 12 or 13, followed by specialization in the mid or even late teen years. As I discussed with the speed plateau above, there is clearly such a thin as training that is too early and specific. That’s why I discuss in the book the paper with this brilliant title: “Late specialization: the key to success in centimeters, grams, or seconds (cgs) sports”
How much, if any, of the difference in performance between male and female athletes is accounted for by genetics? How much of a genetic reason do we have to segregate male and female athletes?
The main difference is the physiology that results from testosterone, and the production of testosterone is initiated by the SRY gene. Testosterone helps account for men’s greater stature, denser bones, longer limbs, more red blood cells, and greater muscle mass. The upper body strength difference between men and women is huge, on average. About the same as between male and female gorillas. To really illustrate the impact of testosterone, I discuss in chapter four athletes who have undergone transitions of their physical sex, and how it has impacted their performance.
Who is your favorite athlete and why?
Sir Roger Bannister. He was the first to break the four minute mile, and then went on to become a world famous neurologist, and I really enjoyed interviewing him.
There are surprise examples in your book of athletes with relatively little training doing shockingly well in Olympic-level competitions. Why is it that these stories are not more common knowledge?
Some of them are common knowledge among people who follow those sports. Chrissie Wellington didn’t sit atop a road bike until age 27, and then won her first of four Ironman Triathlon world titles at 30. Forget 10 years or 10,000 hours, her career from start to finish was only five years, and she never lost an Ironman! She’s very well known in that sport. For the most part, though, I don’t think we generally talk in anything but the most superficial way about the path that elite athletes have taken to get where they are.
How much of an effect does genetics have on the non-physical characteristics required for success, such as motivation or determination?
I don’t know how to quantify it, but it is clearly important. In fact, even some of the strict 10,000-hour advocates concede that individual differences seem to determine who can spend endless hours in focused practice. The heritability estimates of non-physical characteristics that I came across were strikingly high, but heritability estimates have certain limits that I mention in the book. I’m not sure how to put a “how much” on it, other than to say, “definitely some.”
To read more about The Sports Gene visit The Sports Gene: Inside the Science of Extraordinary Athletic Performance

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