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Speaker's Footnotes

Relevant notes and citations provided to TED by David Epstein.

  • 00:13

    The Olympic motto is a wonderful example of a hendiatris, a three-word figure of speech meant to convey a single theme. Another famous Latin hendiatris is Julius Caesar’s veni, vidi, vici. Or one familiar today: sex, drugs, rock ’n’ roll.

  • 01:13

    Ross Tucker, who is based in Cape Town, runs the Science of Sport website, a must-follow for anyone interested in sports science.

  • 02:28

    Leni Riefenstahl, Olympia, Olympia-Film, 1938

    Heroic images of Jesse Owens at the 1936 Olympics are preserved in Olympia, the first documentary feature ever made on the Olympics, produced by film pioneer Leni Riefenstahl. (Riefenstahl, though, is perhaps best known for her 1935 Nazi Party propaganda film, Triumph of the Will.) At 9:10 of this clip, a beaming Owens walks toward the camera after winning a preliminary heat. A few seconds later, you see the next batch of runners digging out their starting holes with gardening trowels.

  • 02:35

    Bruce Schechter, "How much higher? How much faster?," Scientific American, 2000

    A good and accessible read that touches on human limits as well as the importance of technological change is Bruce Schechter’s Scientific American piece. In the article, Gideon B. Ariel, “one of the fathers of biomechanics,” notes that Jesse Owens achieved the same joint speed as Carl Lewis when Lewis set a world 100-meter record of 9.86 in 1991 on a synthetic track.

  • 02:41

    Rolf Graubner and Eberhard Nixdorf, "Biomechanical analysis of the sprint and hurdles events at the 2009 IAAF World Championships in Athletics," New Studies in Athletics, January/February 2011

    Even correcting for surfaces, Usain Bolt is the fastest man in history. And the stride length he achieved while setting the world 100-meter record in 2009 — 9.4 feet per stride — is unmatched, even by other tall sprinters. In the January/February 2011 issue of the journal New Studies in Athletics, scientists referred to the stride length as a “novum,” Latin for a “new thing.”

  • 03:13

    "The Sub-4 Alphabetic Register," Track and Field News, October 1, 2013

    A few months before my tally, Track and Field News published a list of every sub-four miler to that date.

  • 03:18

    I initially read about this phenomenon in New Scientist [paywall]. But I found it a bit hard to believe at first. So I started consulting scientists and engineers, and specifically electrical engineers who give expert testimony in court when a worker is electrocuted. Sure enough, they do see this. The exact result of the electrocution depends on the particulars: how the person was standing at the time and the path the electricity travels. And because electrocution causes this involuntary muscle firing, the engineers advised me that, should I ever touch a potentially live wire, I should do so with the back of my hand. Use the palm, they told me, and the resulting muscle contraction can cause you to grab on the wire and you will be unable to let go!

  • 03:44

    I wanted to be conservative, so I took the lowest estimate that was repeatedly given to me by biomechanists. Several felt that two percent was the right conversion. Had I used that conversion, it would have kicked out a huge portion of the sub-four milers still remaining. Former world record holder Sebastian Coe, legendary for his pacing, raced on both cinders and synthetic tracks, and has said that the difference is about one second per lap, which would be slightly more than 1.5 percent. But, again, I wanted to be conservative so as not to unfairly exaggerate the point.

  • 03:47

    I meant to say “per year,” not “per decade.” That was just a verbal mistake, and I didn’t even realize I’d made it until I saw the video later. Really in the moment!

  • 04:04

    David Epstein, "Sir Roger's Run," Sports Illustrated, July 4, 2011

    I had the pleasure of befriending Sir Roger Bannister in recent years, after writing an article about him. Though he is widely known for breaking the four-minute barrier, Bannister stopped competing at age 25 and went on to become a world-renowned neurologist, helping to extend the life expectancy of patients with autonomic nervous system failure from about three years to around six.

  • 04:12

    Karen Abbott, "The 1904 Olympic Marathon May Have Been the Strangest Ever," Smithsonian Magazine, August 7, 2012

    Thomas Hicks, the 1904 gold medalist, nearly died after the race. (Other runners were unable to finish due to all the dust they were inhaling from passing automobiles.) But Hicks wasn’t even the first man to cross the finish line. Fred Lorz, who reportedly worked as a bricklayer by day, got exhausted at mile nine and so hopped in a car. The car broke down 11 miles later, and Lorz finished the rest of the race on foot, before being disqualified.

  • 04:22

    Elite athletes today may be more savvy about performance-enhancing drugs, but they still sometimes partake in remedies that are bizarre, like deer antler spray, or misportrayed, like anti-aging creams.

  • 05:26

    Edward Pickering, The Race Against Time, Bantam Press, 2013

    Edward Pickering’s book The Race Against Time gives a detailed account of the pursuit of the one-hour cycling record.

  • 06:18

    Dudley A. Sargent, "The Physical Characteristics of the Athlete," Scribner's Magazine, 1887

    “There is a perfect form or type of man,” reads a late-19th-century article enumerating the qualities of an athlete, “and the tendency of the race is to attain this type.” The subtext is that this meant only men and, specifically, white men. At the time, many researchers who studied body types felt that the human physique was distributed along a bell curve, and the peak of the curve — the average — was the perfect form, with everything to the sides deviating by accident or fault.

  • 07:56

    Australian researchers Kevin Norton and Tim Olds have pioneered the study of the “Big Bang of Body Types.” I devote an entire chapter to it in The Sports Gene, and Norton and Olds’ papers and books (including the technical textbook Anthropometrica) are filled with fascinating information about athletic body types. For two of their best compilations, I recommend:

    Kevin Norton and Timothy Olds, “Morphological Evolution of Athletes over the 20th Century,” Sports Medicine, 2011


    Timothy Olds, “Body Composition and Sports Performance,” The Olympic Textbook of Science in Sport, Ronald J. Maughan (Editor), Wiley-Blackwell, 2009

  • 08:20

    Really, it was over the next two seasons, which for such a startling change qualifies as “overnight.”

  • 08:41

    This comes from analysis of data from the National Center for Health Statistics and the NBA’s pre-draft combine. One thing I learned while working with this data was that most NBA players who are reported to be exactly seven feet are shorter when measured at the combine with their shoes off. It looks to me like the measurement that goes into NBA media guides takes the player’s “shoes-on” height from the combine, which is then rounded up to the nearest whole inch. So a player who is 6'10.75" with his shoes off might be 6'11.5" with his shoes on, and will appear as 7'0" in the media guide.

  • 08:49

    I devote a chapter of The Sports Gene to the “Vitruvian NBA player.” Another interesting finding is that the chance of an American man between ages 20 and 40 being in the NBA rises a full order of magnitude with nearly every two-inch increase in height starting at six feet. As teams scoured the globe for taller players, they often found them in countries that have a taller average height than the US. (A tiny difference in average height in a country means a big difference in the number of extremely tall people.) The average height of an American NBA player is a little under 6'7". The average height of a foreign player is 6'9". Many foreign players are in the NBA, it appears, because teams ran low on sufficiently tall players at home.

  • 09:03

    Actually, an armspan-to-height ratio of about 1.01 is typical. So my arms, which are exactly equal to my height, are slightly shorter than most people’s! (I’ll get over it.)

  • 09:18

    In the NBA data I analyzed, the average armspan-to-height ratio was 1.063. For medical context, a ratio of greater than 1.05 is one of the traditional diagnostic criteria for Marfan syndrome, a disorder of the body’s connective tissues that results in elongated limbs.

  • 09:23

    That drawing is of Anthony Davis of the New Orleans Pelicans. He is 6'9.25" with his shoes off, and his “wingspan” is 7'5.5". According to the data I analyzed in The Sports Gene, an NBA general manager who wants to increase his team’s blocked shots would be better off signing a player with an extra inch of armspan than an inch of height. (Anthony Davis is really good at blocking shots.)

  • 09:37

    The “Big Bang of Body Types” chart I displayed earlier used data from men’s sports. (Women didn’t have many opportunities for elite competition in the early part of the 20th century.) The women’s version of the chart would show similar trends, but different specifics, like the gymnasts getting shorter. And women’s basketball players haven’t gotten as tall relative to the general population at the same rate as men’s players. Many tall women opt for sports that have more lucrative opportunities for female athletes, like tennis. At the time I wrote my book, the top three female tennis players in the world had the same average height (5'11.66") as WNBA players.

  • 10:32

    I like photos like this, where you can see that Phelps is easily taller than his coach, but his waist is lower. Phelps isn’t completely unique among elite swimmers, though. At that level, they all tend to have long torsos, and large hands and feet.

  • 10:45

    In fact, humanity has now stagnated in many events where technology isn’t making great improvements. The coveted mile and 1500-meter (the version of the mile commonly run outside the US) records were broken collectively about eight times per decade from the 1950s to 2000, but not at all since. Much of the record-setting that does occur these days comes from populations that weren’t previously competing in high numbers. This free paper, “The Citius End,” shows that many records are hardly improving, or not improving at all. Another free paper shows (in Figure 1) that record-breaking has shifted southward in latitude and eastward in longitude as new populations have joined the competitive sports world.

  • 11:35

    John Manners, "Kenya’s Running Tribe," The Sports Historian, November 1997

    Five American high school boys have run under four minutes in the mile. St. Patrick’s High School, in the Kalenjin training base of Iten, once had four sub-four milers at one time! A good read for background on Kalenjin running is “Kenya’s Running Tribe.”

    Manners, who worked in the Peace Corps in the Rift Valley Province where the Kalenjin live, has partnered with Mike Boit, a former Kenyan Olympian and now a sports science professor in Nairobi, to start KenSAP, the Kenya Scholar-Athlete Project. The program gives a running test and college admissions guidance to top students in the rural western Rift Valley Province. For those who show running potential, their skill can help get them recruited to college. KenSAP has placed students in many of the most prestigious universities in the country. Harvard, with 13, has taken the most KenSAP students.

  • 12:37

    One of my favorite studies showing how brain-imposed limits can be altered is this one, in which the impact of heat on cyclists (the brain forces a slowdown when core temperature reaches about 104 degrees) completely disappears when the cyclists are fooled into thinking the temperature is cooler. The cyclists also reported that they felt better in the “deception” condition even though they got just as hot. In another neat study with competitive cyclists, the athletes rode the same 40-kilometer course four times, getting faster and feeling better each time. In a fifth trial, when information about the length of the course ahead was withheld, their power output plummeted and their feelings of pain and exhaustion skyrocketed. Until, that is, they came into view of the finish, and their brains stopped holding them back.

  • 12:55

    In 2004, the journal Nature had a “Born to Run” cover. The article linked there runs down some of the biological traits that make us uniquely well-suited to running. (And “thanks” to Dennis Bramble, who let me use his phrase: “Apes have no buns!”) The longer and hotter the race, the relatively better humans tend to do. Humans sometimes win the 50-mile Man Against Horse Race in Prescott, Arizona. And San Bushmen in South Africa still hunt by separating an antelope from its pack and chasing it for hours in 105-degree heat, until the animal simply stops running and waits to be killed. With sensible pacing and six months of training, you too can run a marathon!

  • 13:45

    You can follow Kilian Jornet’s summits here. And thank you to Kilian and his team for allowing me to use that photograph!

  • 14:46

    It might seem strange that I wiped my forehead at the end, but it was just a spontaneous release of emotion for me. You probably won’t see it, but when I first stepped onto the red carpet, the slides wouldn’t work! So I was really happy that I ultimately had the chance to get through the entire talk and everything worked.