David Epstein, writer for ProPublica and author of The Sports Gene, talks with EconTalk host Russ Roberts about the book. Epstein discusses a number of the ideas in the book including what we have learned about the nature vs. nurture debate, the role of practice in achieving mastery, why a small part of Kenya produces so many champion marathoners, why major league all-stars can't hit a fast-pitch softball, the strange nature of body types in the NBA and why Michael Phelps's body gives him an advantage.
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Readings and Links related to this podcast
Podcast Readings
HIDE READINGS
About this week's guest:
David Epstein's Home page
About ideas and people mentioned in this podcast:
Books:
The Sports Gene: Inside the Science of Extraordinary Performance, by David Epstein at Amazon.com.
Articles:
"Why MLB Hitters Can't Hit Jenny Finch and science behind reaction time," by David Epstein, at Sports Illustrated.
"Complexity and the Ten-Thousand-Hour Rule," by Malcolm Gladwell at the New Yorker, August 21, 2013.
Sportometrics, by Gerald W. Scully. Concise Encyclopedia of Economics.
Sports, by Robert Tollison. Concise Encyclopedia of Economics.
Web Pages:
Kurtosis. Leptokurtic curves. Wikipedia.
Podcasts, Videos, and Blogs:
Roger Noll on the Economics of Sports. EconTalk podcast.
Leigh Steinberg on Sports, Agents, and Athletes. EconTalk podcast.
Topol on the Creative Destruction of Medicine. EconTalk podcast.
Highlights
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0:33
Intro. [Recording date: August 30, 2013.] Russ: Our topic for today is your book, The Sports Gene. It's a wonderful, fabulous book. I learned many captivating and fascinating things about sports and lots of other topics. It is about sports, but it's really about a lot more than sports. It's about human achievement generally and the age-old question of nature versus nurture, what role do genetics play, what role does environment play. And it's relevant for some of the educational issues we've been talking about, and I expect we'll get into all these over the next hour. I want to start with the role of training and the role of practice in creating greatness. Malcolm Gladwell in his book Outliers put forth an argument that there's something magical about 10,000 hours of practice for creating mastery--in sports, music, and other areas. What's his claim, where does it come from, and what's your take on it? Guest: Well, so, the 10,000 hour rule originates--although it's often called Malcolm Gladwell's 10,000-hour rule--with the work of Anders Ericsson, a psychologist at Florida State; and it comes from one particular study that used 30 violinists who were already so highly pre-screened that they had gained admission to a world-famous music academy. So this is not a study that was set up in a way that can look for the existence of innate talent because it was starting at the very highest level. It's like starting with NBA (National Basketball Association) players and then ignoring that their average height is 6'7" and saying that only practice got them to where they are. And the top 10 from that group average 10,000 hours, not at their peak but by the age of 20. They actually went well beyond that at their peak. But there was quite a bit of individual variation between there. 10,000 was just an average. But some people made it to a certain level faster and others slower. And one of the things that I've pointed out is it isn't in fact a magic number, as it's called in Outliers, because taking the average necessarily obscures all the individual variation that shows up in every single study of any type of skill development. Russ: You give some counterexamples. Dramatic counterexamples. And of course anecdotal evidence can be informative. It can prove that at least the claim isn't always true--it can disprove it, a strong claim. But it is interesting, the variety of success that people achieve with and without training. Obviously most great athletes, most great musicians train like crazy. But not all of them. Tell us about that high jumper. Guest: Right. So in my second chapter I sort of tell a story I call the 'Tale of Two High Jumpers,' in which I sort of profile two high jumpers, one named Stefan Holm, who over the course of 20 years--and by his estimate, 20,000 hours--made incremental progress every year, to the point where he became one of the best high jumpers in the world. And then in 2007 he travels to the World Championships, and is met by a total unknown, a Bahamian jumper by the name of Donald Thomas, who just recently had started high jumping, basically because he had found out he was good at it on a lunchtime bet at his college. And so, Donald Thomas is closer to 0 hours, and Stefan Holm is closer to 20,000 hours. So they average 10,000 hours. But Donald Thomas actually wins that competition. And so I thought it was a good story to explain the fact that not only is there huge variation, but different athletes can get to the same place with both different biology and different training programs. So that nature or nurture question has always been a fallacy. Russ: Now practice does make something. It may not make perfect. It may not get you an Olympic medal. Obviously it can improve almost anything in a trade, whatever level you start with, right? Guest: That's right. When you look at the study of chess, for example, which in many ways has similarities to the kind of perceptual mastery that a quarterback develops, it takes a long time for everyone to become a Grand Master, for example. And it takes thousands of hours. Nobody achieves it before that. That said, the range of variability, the range of time it takes people to get to that level--and many never get to that level--gets enormous, from people who make it in a few thousand hours to people who are at 50,000 hours and haven't made it. So the complex tasks definitely require more practice to achieve mastery. At the same time, the individual variation becomes even larger. Russ: And there's a guy right now who is testing only one data point, but it sure is interesting: a guy who is testing the 10,000 hour thesis with golf. Guest: Yeah. This is Dan McLaughlin. He was a commercial photographer, and his day job was largely taking photographs of dental equipment. And he decided he wanted a life change, so he dropped everything. He read a couple of books that talk about the 10,000 hours, and he decided to put in his first hour of training to be a pro golfer. He got a PGA-certified coach and he's tracking every hour along the route to expertise. He should reach 10,000 hours in 2016. I think he's about a 6-and-a-half handicap now. But he's making this big show of doing the 10,000 hours. But when I asked him, and he told me in the book, he said: Well, I think you could master a task in anywhere from 7000 hours to 40,000 hours. But obviously this 7000-40,000 hour rule doesn't have the same ring to it.
5:57
Russ: But, the real question for me is: I'm 5'6". My NBA career--if I said I'm tired of being the host of EconTalk; I'm going to hire a trainer and become an NBA basketball player--400,000 hours wouldn't do it. And we'll talk in a minute about NBA where you have a lot of interesting things to say and specifically about the NBA. But my point is that, obviously--the 10,000 hour claim is silly. There's nothing magic about 10,000 hours--at 9,999 you are an awful golfer and then that last hour puts you over the top. Guest: And it's way low, for most skills. Russ: Well, that's the crucial question. So if I wanted to become--let's say I wanted to learn to play "The Entertainer," by Scott Joplin on the piano. I've never played the piano. I know what a chord is on the piano. Is it near certain, somewhat certain, that there is some number of hours within a human lifetime that I could master that? If I have virtually no musical ability? Guest: So, first of all, in music and other things like language there are clear developmental windows that you don't want to miss. So, in golf there's less evidence of that kind of window where your genes and your environment need to coincide at a particular time in order to get the best output. But for music, like to have perfect pitch for example, you basically have to have been exposed to music in some major way, probably studying it by the age of 6, or you are just not going to have perfect pitch. Unless you speak a language like Mandarin, which is a tonal language, which can make up for it. So you would be facing the issue of a developmental window. Would you learn to play it eventually? I think you absolutely would learn to play it eventually; but I think it would take you a lot more practice than someone who started earlier and might be more disposed to that. And I don't think you would ever play it as well as them, necessarily. Russ: But, you know, you are talking about a developmental window. You also say in the book, no slow child became a fast adult. So if I'm not sufficiently genetically gifted in running, it doesn't matter how many hours I put in training and lifting weights and training and sprinting and doing the right nutritional things. I'm not going to get there. Guest: Yeah. In running, for sure. So, in contrast to the piano, one of the things we know is important in learning a motor skill--like piano is a perceptual-motor skill--is building myelin, the insulation for your neurons. It's sort of like insulation for a wire, making sure that the signal is being transmitted as fast as possible. And you can, throughout your life, continue to build that. It never stops. It starts to deteriorate and become more difficult when you are older, but you can improve throughout your life. In terms of running, I actually just saw a study--I didn't see this in time to include it in the book because it just came out--of Oklahoma State football players over 4 years of a strength training program, in a major Division 1 program. And they found that lifting weights greatly increased their ability to lift weights in the gym and made no difference to their sprint speed. So, all indications from a huge body of work are that if you want fast adults, you have to start with fast kids. Russ: Did it help anything else, though? Could they lift their suitcases more easily? Guest: I'm sure they could lift a lot more weight. It didn't improve their vertical jump, either, which I was a little surprised at. I think this actually highlights the fact that--and I saw this when I was a national level track runner--is that a lot of the sort of hidebound traditions of strength coaches have athletes doing things that there's no proof that it's linked to their actual performance goals on the field. Russ: We'll come back to weightlifting at the end, because I'm interested in that.
9:44
Russ: Talk about Jennie Finch. There's a great excerpt from your book online. Jennie Finch is one of the greatest, if not the greatest, women's softball pitchers. Talk about what happened when she faced major league baseball players. Guest: This was in 2003; she was invited to participate in a charity softball game. And she was actually only invited as a ceremonial coach originally. She wasn't meant to pitch. But, you know, some of the guys wanted to crank a couple of homers off of her. So, pre-game practice-- Russ: Heh, heh, heh. Didn't quite work out that way. Guest: Yeah. This shows how little athletes know about how they do what they do, I think, because they expected to hit home runs off of her. And because the ball is bigger, and the transit time of the softball pitch at the speed she throws it from a little closer distance is exactly the same as the pitches they face in baseball-- Russ: So it's the equivalent of about 95 miles an hour, from a pitcher's rubber. Major league. Guest: Yep. Which is fast but pretty typical. Jennie throws in the mid-60s, from 43 feet. And they couldn't even hit foul balls off of her. And it turns out that--I thought major league baseball players just have fast reflexes. But it turns out that's not the case. I actually scored faster on a visual reaction time test than Albert Pujols did. Russ: Congratulations. Guest: And the human biology, it's just not capable of tracking an object moving that fast. Russ: I just have to interrupt, David. You are not exceptional on the reaction. It's that Albert Pujols is totally average. Guest: Right. He scored 66th percentile compared to a random group of college students. So a little better than a random group of average of men, random college students. So, the advice to keep your eye on the ball, for example, is nonsense. You can't do it. The angular position is changing too quickly as it gets close to you. And the minimum amount of time it takes to initiate muscular motion in response to something you see is a fifth of a second. And that's half the flight time of the pitch. Just to initiate muscular action. So the way that hitters are actually able to accomplish this is they've learned perceptual cues--like the movement of a pitcher's shoulder before the release, the 'flicker' of the ball--which is the flashing pattern the seams make right when it's released, that basically allow them to predict the future so that they can really decide where to swing long before they have to do it. So it's very much a learned skill. Russ: Well, the other extraordinary thing that you chronicle in there is the eyesight difference. It's not so much reaction time but eyesight. Talk about some of those differences between pro-baseball players and me. Guest: Right. So this is why I use the hardware/software analogy in that section of the book, where I talk about software--these perceptual cues that players have learned are software. It's something that you download, something that you learn. Which is why they can't hit when they have to face someone with an unfamiliar shoulder motion, unfamiliar ball rotation. That said, once you learn those perceptual cues, it is of the utmost importance that you are able to pick them up as early as possible in the pitch, so that you are not left relying on reaction speed. And it turns out that major league hitters have an average visual acuity of about 20/12. Which means that they can see from 20 feet away what I have to move to 12 feet away to see. So they are useless without their learned skills; but once you have those learned skills, you have a better full machine if you also have the hardware that allows you to pick up those cues much earlier. Russ: And that's a common theme of the book, right? What you call the interweaving, the intertwining of acquired skills and genetic or natural ability. Guest: Absolutely. There are no outcomes without both genes and environments. And as much as people sort of want a blanket conclusion about how much of sports expertise is nature and nurture, it very much depends on not only the specific athlete but also the specific sport task. And I try to bring that out in the book.
13:26
Russ: So before we leave the 10,000 hour story: I know that Malcolm Gladwell responded publicly to your book in a recent article, and I know you've appeared with him. What's his response? Guest: I think it's sort of been twofold. So, he said he enjoyed the book and he feels like I made a bit of a strawman argument, with the 10,000 hours. I should say: beyond Gladwell, others have taken a much more strict stance than him. He sort of says on outliers: 10,000 hours is a magic number, but yeah, people are talented, too. Whereas some of the other books and talks, people have said: it's 10,000 hours, there's no room for genes. But Malcolm has said that he--he said yesterday when I was on radio with him that the 10,000 hours shouldn't be applied to sports; that it only should be applied to more cognitively complex tasks. That said, sports scientists who study sports expertise think of the sorts of the sorts of responding and decision-making that athletes have to do as extremely cognitively complex tasks, as complex as anything that we do. So I think sports scientists would argue with him. And his other point was that there are no naturals. Like, nobody learns to be a grand master in chess without thousands of hours of practice. And I don't disagree with that at all. Just like no one learns human language without many, many hours of practice. That doesn't mean that there aren't different abilities to pick it up in the individual variability. Russ: Some exceptionally gifted people get a head start. And as you point out, they also have a head start in their willingness to train, their taste for training, their passion, their will, stamina. There's a thousand things that are mixed in with this, some of which are genetic, some are not. Guest: Right. Exactly. Actually one of the biggest surprises in the reporting of the book for me was sort of that there was plenty of literature showing your training influences your dopamine system--the chemical environment that is involved in pleasure and reward in your brain. I didn't know that there was such voluminous literature showing how your dopamine system in the first place influences your drive to be physically active. That was a really interesting finding for me and an interesting chapter for me to write. Russ: Yeah. You point out there's huge differences in people's disposition to be active. To move around versus to be on the couch. Guest: And of course I picked--I guess intuitively, when I was training I knew that; that I had teammates who had to be managed to train as much as they should, and others who need to be managed to train less. But that line of reporting led to one of my favorite interviews in the book, which is with Pam Reed, one of the greatest ultra-marathoners of all time. When I interviewed her it was the day after she had just finished U.S. Nationals in the Ironman Triathlon, having qualified for world championships. And she really--she's an extreme. She feels uncomfortable when she has to sit still. So, she's at LaGuardia Airport while I'm interviewing her and her flight is delayed, and she's running--so, she's stashed her bags and she's running laps around the parking structure while I'm talking to her. Russ: The day after an ultra marathon. It's extraordinary. Guest: So, that's extreme, but I just thought it was really interesting. So, she herself is always reading studies of how scientists breed mice for their motivation to run, because she's really interested in how she got that way. Russ: Yeah, that's incredible. One last thing--I just want to stick with the 10,000 hours for one more thing. That golfer, you just sort of mentioned in passing and I almost forgot when you said it to ask you. You said he's down to a 6 handicap? Guest: I think he's a 6-and-a-half handicap. Russ: What did he start at? Guest: I don't know--he'd only gone to driving ranges before. He had no experience. Russ: I'm impressed. Guest: He's come a very long way. I think it was astute of him to say, I think you could master the skill anywhere from 7000 to 40,000 hours. Maybe he'll be a 7000-hour guy. I don't know. That said, there's some evidence that he's facing some diminishing returns in terms of his rate of progress right now.
17:15
Russ: Speaking of diminishing returns: you make a fantastic mix of economics and medicine and statistics observation when you refer to an article--you'll tell me when it was written--that predicted that it was only a matter of time before women's world records surpassed those of men in many areas. There were people who were looking at the trend and how the record-setting times in--I forget which sports they were--but some track-and-field and swimming, for women, were improving so rapidly now that women are becoming more athletic, and it was only a matter of time before they surpassed those of men. That didn't happen. Explain what the mistake was. Guest: And those were actually scientific journal articles, from scientists, both in the late 1990s and early 2000s, where they basically looked at trajectory of women's world record progression. So, seeing that women, who basically had been barred from having competitive opportunities, in large part, once they were allowed to compete, the records were coming down really fast. And if you graphed those and extrapolated where they were going, you would see them passing men in every running distance, basically. The problem, I think, was twofold. One was that women had a--they were first in the early part of the learning curve, because they had been blocked from participation. And that's the same thing you see whenever a sport opens up, is you see a quick progression of records that then has diminishing returns. But also, a lot of that trajectory came from the 1980s, what's sort of known as the mega-doping era for female athletes. So, testosterone and its analogs, which are steroids, have a huge impact on female athleticism. And basically all the track-and-field records date back to the 1980s, when we now know, because of released records, there was huge systematic doping in Eastern Bloc countries. And so since that has gone away--not that doping has gone away, but mega-doping is much more difficult to do--women actually appear to be getting slower. And so the biological gap between men and women is now opening, because women can no longer set records, while men occasionally inch forward a little bit--and largely due to Usain Bolt, only. Russ: Right. He's an outlier. Guest: Yeah. For sure. By any stretch. Russ: You do make the observation, which I applaud for its intellectual honesty and the power of the observation: that if genetics didn't matter, men and women should have the same outcomes, just women might have to practice a little longer. But in certain areas they simply cannot and will not, due to muscle mass and other things. They are close in, I think it was swimming is the closest? Is that right? Guest: Long-distance swimming, the performance difference is about 6% at the top end. Russ: Where is it larger? Guest: In running events, in every distance from 100 meters to 10,000 meters, it's 11%, if you take the top 10 men, their average times, versus the top 10 women. And so at 10,000 meters, for example, a man who made the bare minimum qualifying standards for the Olympics would lap the women's world record performance. But the biggest are in throwing events. Russ: Shotput. Guest: Shotput, javelin. So, like, in the javelin, despite the women throwing a lighter implement. And it's still about a 30% difference in performance. Even with the lighter implement.
20:38
Russ: So, let's talk about NBA and basketball. You have a just an extraordinary array of interesting observations about basketball. There was the implication--I think it's in Gladwell; and we'll leave him behind--but I think he talks about how or maybe you generalize--yeah, he says that after an IQ of 120, it doesn't help you that much. I think it's probably not true, but that's his claim. And there's a related claim, or did you make the analogy to height in basketball--after a certain height, it doesn't matter that much? Guest: He made the analogy to basketball. That after a height of about--it's called the 'threshold hypothesis'--that after a certain threshold, more doesn't really matter; you are already good enough. And he put that at about 6'2" for basketball, saying it's better to be taller but beyond 6'2" it doesn't make that much of a difference. And saying, hey, look at Michael Jordan. He's not nearly the tallest guy who has ever played in the NBA. So I kind of set out to evaluate that threshold hypothesis for the NBA. Russ: And you found? Guest: And I found that that's not quite true. So, I found, first of all, to my amazement, that height is a much more narrowly constrained trait than I would have guessed. Russ: What does that mean? Guest: It's--so it's what a statistician would call a leptokurtic curve. So it's an inverted U-curve, but very narrow. Really looks like a mountain. Falls off quickly. So 68% of American men are just in the 6" range from 5'7" to 6'1". And so beyond that it starts falling really, really quickly. So at 6'2", actually, with about every two-inch increase in height, your chances of being in the NBA go up by an order of magnitude. Until it starts to just get silly, like 6'10", you have a 3.2% chance of being a current NBA player--if you are a man between ages 20 and 40; and at 7 feet, there is no percentile from the CDC (Centers for Disease Control) data that I was using at 7', because no 7-footer has shown up in any of their surveys of thousands and thousands of people-- Russ: Because there aren't enough of them. Guest: Right. But if you follow the curve--and I make it clear that it's an estimate--it suggests that if you know a 7-foot man in America who is between the ages of 20 and 40, he has a 17% chance he's in the NBA right now. Russ: Yeah. I'm actually surprised it isn't higher. Because if you are 7 feet--this comes back to the practice point--if you are 7' tall, you have such an advantage, if you can work hard enough, the financial returns are extraordinary. Of course, 17% is a very big number. There probably isn't another profession where more than 17% of the 7-footers are doing it now. So it is basketball-centric. There's no doubt about it. But it is interesting given how lucrative it is, that there aren't more. Guest: For sure. And again, at 7 feet, since there was no percentile, that's very much an estimate. And some people--I've gotten input from people both saying that's got to be too high and others saying that's got to be too low. But let me ask ¬you a question: since you are 5'6" and you talked about the NBA. So, can you touch the basketball rim? Have you ever been able to? Russ: Well, when I was younger, David, I could get my wrist--but no, I cannot touch the rim. Guest: Okay. So the grand total number of men who have been tested in the NBA combine[?] and who can't touch the rim and who have made the NBA is zero. Russ: Shocking. Guest: So there you go. Russ: Well, there's always a first. I could be the white swan who drifts upward into the NBA despite not being able to touch the rim. But it hasn't happened yet, you are saying. Guest: Right. The short players often they both have long arms and so far every one of them has been at least able to grab the rim. Usually much higher than that. But the very short guys in the NBA tend to have unbelievable jumping ability. I mean, 2 of the shortest players in NBA history both won the dunk contest. I think they had other compensatory mechanisms. Russ: So that's Spud Webb? Guest: Spud Webb and Nate Robinson, yeah. And then Muggsy Bogues, who was 5'3", was actually an amazing jumper. He just couldn't palm the ball. Russ: But he could touch the rim. Guest: He could dunk a volleyball. He just couldn't palm the basketball.
24:41
Russ: So, let's talk about armspan, wingspan. That was one of the most extraordinary things I didn't realize, that I learned in your book. Many people have seen the famous drawing--it's DaVinci, right?--of a man circumscribed in a circle with his arms reaching wide and the circle going above his head. So, for the average person, wingspan, tip to tip with your arms extended, is virtually identical to your height. Am I not?-- Guest: A little bit longer. But close. Russ: But out of curiosity, I measured mine; it's exactly the same. Guest: So you are a little shorter than average, then. So am I. I'm exactly the same, which is actually slightly shorter than average. Russ: But in the NBA, it's not like that. And this opens up a whole set of things that we'll talk some about, which is what we think of as specialization, or selection. How certain traits are going to be, in the marketplace, rewarded disproportionately. So, an NBA player's wingspan is on average how much more than his height? Guest: The average ratio is about 1.05, which means that the average NBA player is about 6 and three-quarters and his armspan is about 7 feet. And the short players, if they seem undersize for their position, are often even much longer than that to make up for it. So a guy like Elton Brand--I grew up in Chicago; I remember when the Bulls drafted him at power forward[?], he was about 6'8"; people were saying, you are spending the first pick on a guy who is maybe a little undersized at a power forward[?]. But his armspan is 7'5". So he's a giant among power forwards if you look at it functionally. Russ: And Kevin Durand is also a big outlier on that. Guest: Yeah. A lot of good guys. So is LeBron James. And I wouldn't even--you know what I was surprised by why I was doing that, was the guys that I would eyeball and I would have thought, like, Tayshaun Prince was by far the longest in the NBA. And my eyeball assessment wasn't always right when I turned to the NBA Combine data. I wouldn't have assessed the LeBron James had particularly long arms, but he does. Russ: Are those measurements pretty reliable, you think? From the Combine? Guest: From the NBA Combine they are. So from the media guides and anywhere that you would google a player's height, absolutely not. Russ: Correct. Guest: While I was doing this data[?], I was figuring out how NBA listings actually work. So, most guys who are listed at 7 feet--listed as 7'--in the NBA; you know, when they show it on TV--are actually about 6'10.5". What happens is at the Combine they make them do real measurements, where they have to take their shoes off and get measured. But then for some reason they also measure them with their shoes on. You know, as if they could just get taller shoes and change that measurement. But what guys do in their reported height usually is they take their shoes-on height from the measurements. So, say they are 6'10.5". And with their shoes on they are 6'11.25". And then they round it up to the next inch, so 6'10.5" goes to 7' in most cases. Russ: Okay. From now on I'm saying I'm 5'9". Guest: Except for Shaquille O'Neal, who is a true 7'1" with his shoes off. Russ: And his shoe is about, what is it, like a 30. Guest: He probably compresses it a lot, though, too, so he might not get as much height advantage out of it. Russ: Now, talk about Marfan Syndrome. Which I didn't fully understand. You mention it in the book a couple of times. Isn't one of the symptoms of Marfan Syndrome that phenomenon, longer wingspan than height? Or is that not right? Guest: Yes, that's absolutely right. Marfan Syndrome is a disease of the connective tissue that can be fatal because that includes your coronary artery, which can rupture because of a problem with the connective tissues. And one of the most conspicuous signs of Marfan Syndrome is elongated limbs, very long hands and very long arms. And often being very tall. And actually, a woman who was maybe one of the greatest volleyball players in American history named Flo Hyman, who was 6'7", actually died on the court, and it turned out she had Marfan Syndrome. But one of the diagnostic criteria is the length of arms to the height. Russ: So, do some NBA players have it? Guest: I'm sure some NBA players do. And others get evaluated for it. And other people with long arms as well. So, Michael Phelps, who has pretty long arms compared to his height, he wrote in one of his autobiographies that he was getting checked for it every year when he was a kid, because some doctor looked at his armspan and said, We should keep tabs on you. So, it's often the case that people have long arms; they don't necessarily have it, but they will have been checked for it by an astute doctor. Russ: While we're on Michael Phelps, tell us why his body, what's unusual about his inseam and why that helps him. That fascinated me. Guest: So, Michael Phelps is 6'4", and he has the same size pants as the guy who is 5'9" and holds the world record in the mile. And that guy has extraordinarily proportionally long limbs; and Michael Phelps has extraordinarily proportionally short limbs. Michael Phelps has this interesting mix of short legs, long torso. You want a long torso in swimming. That's the best. It's like a long canoe. And long arms. He has long arms and short legs. Which is unusual. That said, there are other guys at his level who have that. He is not like alone on this body-type island in elite swimming. There are others who have it. Russ: I assume not.
29:46
Russ: Let's talk some more about body shape. If I think I understood it correctly, you made the argument in the book that if you simply had the height and weight of an Olympic roster, you could do a pretty good job of guessing what their events are. Is that correct? Guest: That's definitely correct. I don't think you would get every person accurately, but I think--having competed at the national level of track and field, I think you would get the vast majority of them correctly. And frankly, you could definitely do it easily if you had them charted on a height-and-weight graph, and I think you could do it for most positions in something like football as well. Russ: One thing I learned that made me feel better, because I couldn't understand why the NFL (National Football League) running backs in recent years are so short. I found that strange. And so you have a lot of people like Ray Rice, who is listed--again, some of these people are not listed, I'm sure, at their actual height--but they are listed at 5'8", 5'9", 5'10". I'd think, well, wouldn't it be better to have a running back who is 6'2" or 6'3"? There used to be some--Larry Johnson was a large running back. They could bowl people over, they'd be hard to tackle. Then you think, well maybe if they are low to the ground they are harder to tackle; people claim they "have a lower center of gravity." As if somehow that's a magical advantage. But that's not their advantage. It's something else. Guest: Yeah. And there still are some big running backs. But they are increasingly rare. And even as humanity has gotten taller, running backs have gotten shorter. So, in the shortest running distances it's actually an advantage to be short. So, shorter limbs have less what's called 'moment of inertia'--it's less resistance to beginning to be in motion. And so in any running task that is mostly comprised of acceleration, as opposed to top speed, being small and actually having short legs is really advantageous. Look at a guy like Manti T'eo, who was the best defensive player in college football last year. When he went to the NFL Combine, he ran a terrible 40-yard dash. And everyone said, well, maybe he's not as good as we thought. And he has short legs. But he ran a great 10-yard dash. And that's really what he's going to do on the field. And so running backs are very rarely running full speed. They are starting and stopping. Most of what they do is acceleration and deceleration, and in that it's actually an advantage to be small. Russ: So, I'm readjusting my professional aspirations now from basketball to football. Because at 5'6" I have a huge advantage over Ray Rice. So, of course, there's other factors, but once you are selecting for quick starts, say, sprinting, or once you are selecting for long distances in the Olympics, say marathoning, it can be very difficult for a person without the ideal body type to compete because it's just a huge disadvantage. Guest: Right. So there are people who find compensatory mechanisms, but all things being equal, those advantages are a big deal. And I don't know what Ray Rice's listed height is, but having stood next to him, I'd be shocked if he's actually over 5'8". And I wouldn't be shocked if he's under. Russ: Why are marathon runners small? Guest: So, in the marathon, it's sort of twofold. One reason is because one major limiting factor in endurance is your ability to dissipate heat quickly. So at about 104° core temperature, you will slow down or stop. Unless you are taking amphetamines, which sometimes will override that and cause people to cycle or run until they have heat stroke. But you have to unload heat. And the greater the surface area of your body is compared to your volume, the quicker you unload heat. It's just like a radiator that has coils. The point of the coils is to increase the surface area to the volume to let the heat get out. And that becomes a really big advantage, because we know the limiting factor of heat dissipation. Smaller people also--because as you grow in height, your volume increases in 3 dimensions, while your surface area only in two. So you actually become sort of heavier for your size, which can be a disadvantage for running economy as well. Russ: And who is the woman, the tall woman marathon runner, who is great in cold weather but not in hot? Guest: Paula Radcliffe. She's about 5'8". Which for a female marathon runner at her level is gigantic. She's like, literally there are women below her shoulder and she's running next to them. Russ: What are they usually? Guest: 5'2", 5'1"; there would still be some 4'11" people who win major races in Olympics. There was a 4'11" Olympic champion recently. Hovering right around 5 feet, often. And that's not to say there can't be taller ones. But it's quite rare and they absolutely don't win when it's hot. Like if you want to place your bets, when it's hot you can just basically scratch off someone like Paula Radcliffe. Russ: And she's undefeated in the winter. Guest: Yeah, in the prime of her career, she was so dominant. She won I think like 7-0 in fall marathons. And in the summer Olympics, in warm-weather marathons, she was never even a factor in the race.
34:47
Russ: Let's talk about speed and running. In the history--I'm quoting you from the book--in the history of American running, 17 men have run a time faster than 2 hours and 10 minutes for the 26.2 marathon. I'm not one of them. I did break the 4.5-hour mark; in 1976 in the one marathon I competed in. Guest: Good for you. Russ: And I'm short, too; you'd think I could have done better than that. But it wasn't enough. So I didn't break 2 hours and 10 minutes. But 17 men in history have. In American history. And yet, in October of 2011, 32 men from one part of Kenya broke 2-10. Guest: From one tribe. That's right. That's about a 4-58 mile pace, I think. And yeah, 32 Kalenjin men, from the Kalenjin tribe, which is--so in the United States we think of Kenyans as being great marathon runners, but when I went to Kenya for the book, they think of the Kalenjin as being great marathoners. That's not to say that there aren't great marathoners from other places, but that's a minority tribe in Kenya, about 10-12% of the population. And it's over 80% of the elite runners. Russ: I think I would need more than 10,000 hours to run a half a mile in 2.5 minutes, the pace at which they are running 26 consecutive miles. So this has intrigued a lot of people. And the other intriguing thought is that a very small country, Jamaica, has some of the fastest people in the world at short distances. Usain Bolt. What do we think is going on there? It's not so straightforward, is it? Guest: No. It's pretty complicated. Let me start with the nature part. So, every man who has been in an Olympic 100-meter final since the boycotted games of 1980, whether his homeland is the United States, Canada, Jamaica, Netherlands, Portugal--every single one has his ancestry from a small swath of west Africa. And that area happens to have people that tend to have, just on average, a slightly higher proportion of fast-twitch muscle fibers. The kind that contract really explosively for activities like sprinting. So they have low-latitude ancestry, so they have evolved the adaptation of long limbs proportional to body type--good for running, bad for swimming, to unload heat--and they have a shift toward, just on average, a higher proportion of fast-twitch muscle fibers. So you have a population that, all other things being taken into account, in general you find more people who are fit for explosive sports. But that said, it can't be all genes because there are more people of Jamaican descent in the United States than there are in Jamaica. So it can't come down only to genes, so [?] some of those other factors as well. Russ: Because the American teams should be world class using just Jamaicans in America? Guest: Yeah. And we are world class, but we are still getting our tails kicked by Jamaica. And I think that--Jamaica is really making the most, with its culture around sprinting, of the talent pool that it does have. I mean, it's like high school track-and-field there is like Texas high school football here. With shady boosterism and all. When I went to the National High School championships, which is over 30,000 people like packed into a stadium, it's like a World Cup atmosphere for high school kids--I was asking coaches about recruiting and they would tell me: Well, we're not allowed to give refrigerators to parents any more in an effort to get their kids to come to our school. I didn't even ask them that, but apparently there's all sorts of shady recruiting going on. And that event, it's the National High School championships. They didn't even care about pro-sprinting in Jamaica. There was no attendance at pro meets until the Asafa Powell-Usain Bolt showdown before the 2008 Olympics. They would draw bigger crowds for the 5- and 6-year old kids' national championships. So there really are a lot of emphasis and a lot of fun events around youth sprinting in Jamaica, and the chances of a fast kid slipping through the cracks in Jamaica is like the chances of a good football player slipping through the cracks in the United States. Russ: Yeah. I'm actually a big fan of shady recruiting practices. I think athletes should get at least refrigerators, or their parents. I think that's probably good. I don't know who is getting the rents that used to go to refrigerator-giving. Guest: I'm sure they are figuring out something. Russ: I bet they are.
39:06
Russ: So that's sprinting. The Kenyan case in the marathon and the longer distances was quite fascinating. There's a wad of different hypotheses and theories. What are some of them, and what do you think we know and don't know? Guest: What's quite well-evaluated is that the body type--not necessarily of Kenyans but of the Kalenjin tribe in particular, is very well-suited to long-distance events. So, they have--this is as low-latitude ancestry population as you can get. I was crisscrossing the equator when I was visiting them, and in the hot and dry climate they have extremely narrow pelvic breadth. So when you are evolving in a low-latitude environment with a hot and dry climate, you tend to follow something called Bergmann's Law, which means you have--whatever organism you are, if you are human or other animal--more narrow pelvic breadth. And Allen's Law, which is the closer to the equator you are, the longer your limbs are compared to your body size. Russ: Just to generalize: Aleuts, people who used to be called 'Eskimos'--you mentioned it's not necessarily the politically correct term--but people who live in igloos tend to be short and stocky. And people who live near the equator tend to be tall and narrow. Guest: That's right. And there's some variation depending on the microclimate, so if the people at the equator are in the rainforest, that can alter it somewhat. Like it was the case for the Kikuyu, which is a larger tribe in Kenya. But yeah. So theoretically the ideal body type for heat conservation at the North Pole would be a sphere. And so people tend toward that shape, which is they have a large volume upstairs[?] to retain heat, and they have short legs. And so they are becoming more spherical. Russ: It's awesome. It's like the earth. The earth's not really a sphere. It took millions of years of rotation to round off its rough edges. But that's not exactly what's happening. But it's the same process, I guess. Guest: And a pole would be the best at the equator, because that would unload heat through every surface and have a very small volume. And the reason that's important for running is that it's really important to have what's called 'low distal weight' in running, which means very little weight away from your center of mass. So, your leg is a pendulum, basically. And the longer and lighter it is, the easier it is to swing. So, in a laboratory setting, when an 8-pound weight is strapped around a runner's waist, it increases energy consumption to run at a given pace about 4%. But if you take the same weight and put it in the form of two 4-pound weights on the ankles, it increases energy consumption 24%. So where the weight is, is critical. And the build of the Kalenjin, what is called the Nilotic body type, is what anthropologists call it, is on average really good for efficient running. And what studies have shown is that it's not that Kenyans compared to like Danish runners, which is what some of the studies evaluate, they don't have a greater ability to use oxygen overall. But they get a much better pace for a given amount of oxygen because their running economy is so good. Russ: And the oxygen issue arises because--I assume, I don't remember--but I assume the Kalenjin are at altitude. Guest: The Kalenjin are at altitude, but more importantly, because there's been this rhetorical question-- Russ: That's this issue whether training, being born at altitude--being born a mile high or a mile and a half high is an advantage or not. Because it seems to be. It certainly is an advantage if you show up at their track out of the blue, that you are going to struggle. Guest: No question. You'll actually, if you just show up, you'll be hyperventilating sort of without knowing it while you get used to the elevations. So there's been this rhetorical question in track and field for years, about, well, if it's just the altitude, then why aren't Tibetans dominating? And there are a number of reasons why that's kind of a fallacy. One is because their climate is quite different and they are not as linear. Two, they are too high for the kind of intense training. There is sort of an altitude sweet spot where you get the increase in red blood cells and this adaptation to the lower oxygen but you can still run hard. But really, an important factor is, what you want is to be not genetically adapted to altitude. So you want to have sea-level ancestry so that when you come up to altitude, you increase red blood cells. So, Tibetans have a gene that stops them from overproducing red blood cells at altitude so their blood doesn't get too thick. So they don't get one of the changes that runners want when they go to altitude. So you want sea-level ancestry but to grow up at altitude. Because then you'll have the increased red blood cells, and if you are there before puberty, you'll have a higher surface area for your lungs, which is better for diffusing oxygen in the blood. And that is exactly the case of the minority tribes in Kenya and Ethiopia that dominate running, is they have sea-level ancestry but in recent history moved into altitude, to mid-level altitude. Russ: And how much training are they doing? Guest: A lot. And it's not systematic training though. I thought maybe there would be some coaching secrets in Kenya. But like a lot of gold medalists don't even have coaches. But what they do have is, first of all a lot of them have grown up running to and from school, so they sort of know who the faster kids are; and they are primed for training, partly because they are used to running and they are not overweight. So, I think there are plenty of people with talent for running who won't find out because you are not prepared to start trying to train if you are overweight, basically. So these kids will grow up running to and from school. And then there's no opportunity cost for them to try training. So, I remember in 2008-- Russ: Because they have such a poor country. Guest: That's right. That's why all the runners are coming from these impoverished rural areas. In 2008, in the United States, there was a guy named Brian Sell who was on the U.S. Olympic marathon team. And he was putting off dental school to chase his Olympic dream. There's no putting off dental school in rural Kenya. Unfortunately. So guys will wander literally off of subsistence farms in sandals and try to run an interval next to a Geoffrey Mutai, who won the Boston marathon. They'll literally do that. So there's no opportunity cost. And most of them will fall by the wayside, because they can't do that. And a couple will be able to stick with it. And that's where the world beaters come from.
45:09
Russ: How far have we gotten in identifying the genetic basis for some of these traits that you've mentioned that are beneficial for athletes? Guest: So, it's a big mix. We've gotten not far in identifying the genes that are associated with learning motor skills. That said, there is some early work now on a gene, for example, called BDNF, which is Brain-Derived Neurotrophic Factor--and I actually cut this one from the book because I had to cut a lot of space. But there are different versions that involve metabolism of brain chemicals. And people with certain versions seem to retain--they seem to learn motor skills quicker, and forget less often; they are made to sort of simulate driving along some sort of course that they retain the memory of where they are supposed to be going better and they pick up the skills quicker. That said, most of the genes involved in motor skills--we know that genes are involved from twin studies and things like that, but we don't know what they are. In other skills, like endurance training, exercise genetics is really rewriting our whole notion of talent, from something that pre-exists the opportunity to train, which was literally the definition in a lot of sports psychology papers until recently, to your biological setup that allows you to profit from training more rapidly than the next guy. For the book, I got tested for some of those genes that predispose one to being what's called a 'high responder' to training. And sure enough, I had a lot of genes that predispose me to having a rapid response to endurance training. Which is exactly what I saw in my athletic career, where I didn't start out that well but I progressed at a much faster rate than some of the guys I was training with. Russ: Yeah, you give the example in the book of Jim Ryan, who I remember from my youth, who was the record mile holder, as somebody who just exploded, from being an okay runner to a world class runner, by some practice. Guest: Yeah. He went from running a 5-38 mile to a 4-08, basically in a season. Obviously that's extreme. There are also two genes in the book that I highlight that are unusual in the fact that--the more study there is, the less it looks like single genes have huge effects in most cases. So there are some diseases where we know that's the case, but they are the minority. But there are two genes I highlight in the book where a single version of a gene has made a huge difference to an individual's athletic performance. Those are few and far between but those cases do exist. Russ: I want to come back to those, but I first want to emphasize, because one of the themes of this program is the role of complexity and the difficulty we have in untangling causation: a theme that comes up in the book now and again is that the relationship between particular genes and outcomes are much more complicated than we originally thought. Guest: Yeah. Much. Basically, when the human genome was sequenced a decade ago, there was some wishful thinking from scientists. And it was interesting to go look up old articles, where you'll see people saying: Well, now we've got the whole instruction manual for the human body; in 5 years you are going to be carrying around your genome on a card in your wallet and present it to your doctor. And so 10 years later, not even close. And so it turns out that genetics has been more complicated at sort of every possible turn. The main initial complication being that genes work in networks and rely upon one another. So they have to be studied in networks most of the time. So if you change one gene, it might change how the others are functioning. And they have differential response to different environments. And many of them have effects that are so small on their own that the studies that were conducted looking at them were too small to detect that effect. We are now coming around to more novel ways of studying and making more progress, but it's been much more complicated than originally thought.
48:59
Russ: So, there's a nice statistic in the book. You say--this is a quote: "In 1975, athletes in the major American sports averaged roughly five times the median salary for an American man. Today the average salaries in those sports are between 40 and 100 times the median full-time salary." And that's a revolution that's due to technology, the ability to sell your services around the world effectively; you have more bidders but you also reach more people through television, the web, the net. Everything has just changed in sports. And it reinforces a point I like to make, that there are different sources for inequality. And some of those sources are not political; they are not a conspiracy. It's what Sherwin Rosen and Ed Lazear in a paper called "The Economics of Superstars" that's been taken and written about by a lot of people, that the very high end of the skill distribution in lots of areas get a lot more money than they used to. One of the things that's done is of course we've already talked about--it's changed what sports people go out for; it's a lot more expensive to miss your ideal sport, so people switch sports to the ones that are the most rewarding economically and financially. They still do some things they might love, but the cost has gotten higher of doing that. And it's also led to some genetic testing and some market opportunities for people that may not be so successful or may be so attractive. Talk about what the role of money in sports is doing with that genetic overlap. Guest: Well, so I think there are two sort of different issues there. One is that explosion of potential compensation for sports has led to really a worldwide talent search. And to many more people in different parts of the world wanting to participate in those sports if they can. Like you mentioned for 7-footers. Give it a shot; this is a potentially hugely lucrative lifestyle. And that's led to this extreme specialization of body types in sports. Where, in some of the sport psychology literature, because athletes have gotten better and better, the papers will argue: Well, they've gotten better so much faster than genes could have evolved, so it must be practice. But that's not the case. The gene pool in the sports has changed for sure. The proportion of NBA players that were 7 feet doubled like almost overnight when the league became very lucrative. Russ: That's because people were practicing getting taller. Guest: Yeah, right. But it's gone down even to the micro level, to things you wouldn't expect. Like water-polo players now have longer proportional forearms to their total limb because it helps for throwing than they did in the past. So it's even gone to the micro level. I likened it to these athletic bodies fitting into their sporting niches like Darwin's finches' beaks fit into their niches. And the scientists sort of found[?] tracked[?] this trend, called the 'big bang of body types' because the body type for any given sport is getting weirder and blasting apart from all the others. So, female gymnasts in the last 30 years have shrunk on average from 5'3" to 4'9". But yeah, so the gene pool really is changing in sports. But you also mentioned the kind of--I think you were getting at the direct-to-consumer genetic testing? Russ: Yeah, yeah, because that interested me, too. Guest: So, that is exploding faster than anybody is discussing yet. There are now plenty of companies that will test your genes for you. And I've participated in a couple of those. But in most cases the marketing is way ahead of the actual science. So the most popular gene test that is offered to parents is the ACTN3 gene, the so-called 'sprint gene,' because it's for a protein found in fast-twitch muscle fibers. And if you have the so-called 'wrong' version, you are just not going to be in the Olympic 100-meter final. I'm sorry, like that's just a fact. But if you do, that only rules out about a billion of 7 billion people on earth. So this test is being marketed to parents, saying, like, Take this and find out if your kid is going to be a sprinter. Well, fine, so he's lumped in with the other 6 billion instead of the 1 billion. It counts for a small amount of variance at the top level. So the marketing is well beyond what it should be. That said, there are some tests, for things like a gene that we know predisposes kids--or anybody--to permanent brain damage if they take hits to the head like in football. That one I'm frustrated there's not more marketing behind it, because people aren't really aware of it. And that one I think people should take advantage of.
53:18
Russ: You close your book with the story of one of the greatest cross country skiers of all time, and Olympians. Talk briefly about what role genetics played in his story. Guest: Yes. This is a man named Eero Mantyranta, and he was, in the 1960s, possibly the greatest endurance athlete in the world. Certainly up there. He won several Olympic medals, three of them gold. He came from this tiny arctic hamlet and didn't even really know what it was to be a professional athlete. But he had grown up skiing across a frozen lake to school, very much like a Kenyan kid does for running, and just wanted a better life. And realized he had a pretty good talent for cross-country skiing. But when he would be examined medically, he had this huge proportion of red blood cells. Much, much bigger than is normal. So he looked like even an extreme version of athletes who are doping by using the hormone EPO (erythropoiesis), which is what Tour de France cyclists made famous, basically. It's a synthetic version of a hormone in the body that cues your body to produce red blood cells. And so it was assumed that Eero was somehow finding a way to blood dope. And that that was the cause of his success. But 20 years after he retired, a group of scientists who got curious, who were finding these high blood levels in other members of his family, came and examined the whole family and found that some of them had this rare version of the EPO receptor gene. There are receptors like a lock and others like a key and when they are put together, stuff starts happening. And they had a rare version of this EPO receptor gene and it caused the body to be extremely overly sensitive to EPO and to go crazy producing red blood cells. And that's what gave Eero this incredible oxygen delivery capacity. So, other members of his family that have the gene, like his nephew, also won a gold medal. And members of the family who don't have it are not good ski racers. So I thought that was a really interesting example and a rare case where a single gene makes a huge difference. Russ: It's a beautiful story, and you write very eloquently about your visit to his place in the middle of nowhere-- Guest: A farmer in the arctic, yeah. Russ: But what fascinated me about this story is--resents might be too strong a word, but he's not--he doesn't believe, he doesn't like believing, and I understand this, that he had a genetic advantage. Guest: Yeah. That's right. And that actually was surprisingly rare when I tal