The Big Bang of Body Types
Decades ago, particularly in Europe, local club sports teams supported a large number of regionally competitive, or even semiprofessional, athletes who often made up humanity’s elite performers. Until technology tilted the landscape.
Today, literally billions of customers have a ticket to the Olympics, the World Cup, or the Super Bowl with the flick of a remote control. As a result, most sports enthusiasts are now spectators to the elite as opposed to participants in the comparatively quotidian, a huge population of recliner-bound quarterbacks paying to watch a tiny number of real QBs. That scenario creates what economist Robert H. Frank termed a “winner-take-all” market. As the customer base for viewing extraordinary athletic performances expanded, fame and financial rewards slanted toward the slim upper echelon of the performance pyramid. As those rewards have increased and become concentrated at the top level, the performers who win them have gotten faster, stronger, and more skilled.
A group of sports psychologists, particularly acolytes of the strict 10,000-hours school, have argued that improvements in individual sport world records and team sport skill levels have increased so vastly in the last century—faster than evolution could have significantly altered the gene pool—that the improvement must come down solely to increasing amounts of practice. As the rewards for top performers have grown, more athletes have undertaken greater quantities of practice in an attempt to earn them.
A portion of the improvements, though, even in straightforward athletic endeavors, are very clearly the result of technological enhancements. Biomechanical video analysis of legendary sprinter Jesse Owens, for example, has shown that his joints moved as fast in the 1930s as those of Carl Lewis in the 1980s, except Owens ran on cinder tracks that stole far more energy than the synthetic surfaces where Lewis set his records.
But technology is not the only source of improvement that is often overlooked. Undoubtedly, the increasing amount and precision of practice has helped push the frontiers of performance. But the winner-take-all effect, combined with a global marketplace that has allowed many more people to audition for the minuscule number of increasingly lucrative roster spots, has indeed altered the gene pool. Not the gene pool in all of humanity, but certainly the gene pool within elite sports.
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In the mid-1990s, Australian sports scientists Kevin Norton and Tim Olds began compiling data on the body types of athletes to see whether there had been significant changes over the twentieth century. The sports science, after all, had changed drastically.
In the late nineteenth century, researchers of the science of body types—known as anthropometry—arrived at conclusions influenced by classical philosophy, like Plato’s concept of ideal forms; by art, such as Leonardo da Vinci’s Vitruvian Man, the famous depiction of a man’s body inscribed in a circle and square indicating the ideal human proportions; as well as by racially charged agendas. “There is a perfect form or type of man,” reads a late-nineteenth-century article enumerating the characteristics of an athlete, “and the tendency of the race [i.e. the white race] is to attain this type.”
At the time, anthropometrists felt that 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. So they asserted that the best athletes would have the most well-rounded, or average, physical builds. Not too tall or too small, neither too skinny nor too bulky, but rather a just-right Goldilocks-porridge version of a man. (And it was only men.) That was the belief for any sport: the average human form would be ideal for all athletic pursuits. This confluence of subjective theory and philosophy dominated the agenda for coaches and physical education instructors in the early twentieth century, and it showed in athletes’ bodies. In 1925, an average elite volleyball player and discus thrower were the same size, as were a world-class high jumper and shot putter.
But, as Norton and Olds saw, as winner-take-all markets emerged, the early-twentieth-century paradigm of the singular, perfect athletic body faded in favor of more rare and highly specialized bodies that fit like finches’ beaks into their athletic niches. When Norton and Olds plotted the heights and weights of modern world-class high jumpers and shot putters, they saw that the athletes had become stunningly dissimilar. The average elite shot putter is now 2.5 inches taller and 130 pounds heavier than the average international high jumper.
On a height-versus-weight graph, the duo plotted the average physiques of elite athletes in two dozen sports; one data point for the average build of an athlete in each sport in 1925, and another for the average build of an athlete in that same sport seventy years later.
When they connected the dots from 1925 to the present for each sport, a distinct pattern appeared. Early in the twentieth century, the top athletes from every sport clustered around that “average” physique that coaches once favored and were grouped in a relatively tight nucleus on the graph, but they had since blasted apart in all directions. The graph looked like the charts that astronomers constructed to show the movement of galaxies away from one another in our expanding universe. Hence, Norton and Olds called it the Big Bang of body types.
Just as the galaxies are hurtling apart, so are the body types required for success in a given sport speeding away from one another toward their respective highly specialized and lonely corners of the athletic physique universe. Compared with all of humanity, elite distance runners are getting shorter. So are athletes who have to rotate in the air—divers, figure skaters, and gymnasts. In the last thirty years, elite female gymnasts have shrunk from 5'3" on average to 4'9". Simultaneously, volleyball players, rowers, and football players are getting larger. (In most sports, height is prized. At the 1972 and ’76 Olympics, women at least 5'11" were 191 times more likely to make an Olympic final than women under five feet.) The world of pro sports has become a laboratory experiment for extreme self-sorting, or artificial selection, as Norton and Olds call it, as opposed to natural selection.
Big Bang data in hand, Norton and Olds devised a measure they called the bivariate overlap zone (BOZ). It gives the probability that a person randomly selected from the general public has a physique that could possibly fit into a given sport at the elite level. Not surprisingly, as winner-take-all markets have driven the Big Bang of body types, the genes required for any given athletic niche have become more rare, and the BOZ for most sports has decreased profoundly. About 28 percent of men now have the height and weight combination that could fit in with professional soccer players; 23 percent with elite sprinters; 15 percent with professional hockey players; and 9.5 percent with Rugby Union forwards.
In the NFL, one extra centimeter of height or 6.5 extra pounds on average translates into about $45,000 of extra income. (Particular professions that require unique physiques have an even more concentrated winner-take-all structure and outdo even professional sports. The BOZ for regional catwalk models is less than 8 percent, dropping to 5 percent for international models, and to just 0.5 percent for supermodels.)
And the Big Bang of body types goes down to the body-part level as well. While tall athletes have grown taller at a much faster rate than humanity as a whole, and small athletes have shrunk relatively smaller, athletes in certain sports have increasingly needed extremely specialized body traits. Measurements of elite Croatian water polo players from 1980 to 1998 show that over two decades the players’ arm lengths increased more than an inch, five times as much as those of the Croatian population during the same period. As performance requirements become stricter, only the athletes with the necessary physical structure consistently make the grade at the elite level. The shorter-armed athletes are more often weeded out.
In addition to having longer arms overall, the bone proportions in the arms of top water polo players have changed. Elite players now have longer lower arms compared with their total arm length than do normal people, giving them a more efficient throwing whip. The same is true of athletes who need long levers for powerful, repetitive strokes, like canoeists and kayakers. Conversely, elite weight lifters have increasingly shorter arms—and particularly shorter forearms—relative to their height than normal people, giving them a substantial leverage advantage for heaving weights overhead. One of the many failings of the NFL combine that tests prospective draft picks in physical measures is that arm length is not taken into account in the measure of strength. Bench press is much easier for men with shorter arms, but longer arms are better for everything on the actual football field. So a player who is drafted high because of his bench press strength may actually be getting a boost from the undesirable physical characteristic of short arms.
Top athletes in jumping sports—basketball, volleyball—now have short torsos and comparatively long legs, better for accelerating the lower limbs to get a more powerful liftoff. Professional boxers come in an array of shapes and sizes, but many have the combination of long arms and short legs, giving greater reach but a lower and more stable center of gravity.
The height of a sprinter is often critical to his best event. The world’s top competitors in the 60-meter sprint are almost always shorter than those in the 100-, 200-, and 400-meter sprints, because shorter legs and lower mass are advantageous for acceleration. (Short legs have a lower moment of inertia, which essentially means less resistance to starting to move.) Sprinters hit the highest top speeds in the 100- and 200-meter races, but the 60-meter race has a proportionally longer acceleration period. Perhaps the advantage of shortness for acceleration explains why NFL running backs and cornerbacks, who make their livings starting and stopping as quickly as possible, have gotten shorter on average over the last forty years, even while humanity has grown taller.
On occasion, technique changes in sports have changed the advantaged body types almost overnight. In 1968, Dick Fosbury unveiled his “Fosbury flop” method of high jump, which gives an advantage to athletes who have a high center of gravity. In just eight years after Fosbury’s innovation, the average height of elite high jumpers increased four inches.*
In other cases, body types have more nuanced effects. While smallness is generally a boon for endurance runners, Paula Radcliffe, the world record holder in the women’s marathon, at 5'8" is literally head and shoulders above most of her world-class competitors. It didn’t keep the iconically tough Brit from winning eight marathons in the prime of her career, 2002 to 2008. But Radcliffe’s size may have helped confine most of her victories to autumn. One reason that marathon runners tend to be diminutive is because small humans have a larger skin surface area compared with the volume of their body. The greater one’s surface area compared with volume, the better the human radiator and the more quickly the body unloads heat. (Hence, short, skinny people get cold more easily than tall, hefty people.) Heat dissipation is critical for endurance performance, because the central nervous system forces a slowdown or complete stop of effort when the body’s core temperature passes about 104 degrees.*
While Radcliffe in her prime was unbeatable on autumn mornings when races were held in cool temperatures, she was feckless in summer heat. At the Athens Olympics in 2004, when the marathon was held in 95-degree heat, despite having by far the fastest time coming into the race she was unable to finish and crumpled in a heap by the side of the road. The woman who won the race was 4'11". At the Beijing Olympic marathon in 2008, the temperature was 80 degrees and humid and Radcliffe finished a distant twenty-third. From 2002 to 2008, Radcliffe was 8-0 in marathons contested in cool or temperate conditions, and 0-2 and never even in contention in the sweltering summer Olympic races.
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Collecting data for the most famous study of athletic body types ever conducted took an international research team a full year and included 1,265 athletes who competed at the 1968 Mexico City Olympics, representing every sport (except equestrian) and 92 different countries. It took six more years for the results to be compiled and published in a 236-page book. Half the book is simply tables of body measurements. Even without text, they convey an obvious message: in most Olympic sports, athletes are generally more physically similar to one another than I am to my own brother.
Within track and field, most of the athletes could be pinned to an event simply by their body measurements. The men and women who raced the 400- and 800-meters or the high hurdles were the tallest of the runners—no surprise, given that the goal in hurdling is to clear the barriers with as little movement of the center of gravity as possible—while the marathoners were the shortest. No surprise there, either. But the similarities extended to less obvious physical traits of the skeleton.
Athletes in a sport or event tended to be similar in height and weight—and often different from a control population of nonathletes—and also with respect to the breadth of their pelvic bone and the skeletal structure of their shoulders.
Nonathlete women who were measured as a control group for the study had, of course, wider pelvic bones than nonathlete men. But female swimmers had more narrow pelvic bones than the normal, control population of men. And female divers had more narrow pelvic bones than the female swimmers. And female sprinters more narrow than the female divers. (Slim hips make for efficient running.) And female gymnasts had slimmer hips still.
Female sprinters had much longer legs than the control population of women, and about as long as the control men. Male sprinters were around two inches taller than the control men, and 100 percent of that was in their legs, such that when they were seated the sprinters were the same height as the control men.
The male swimmers were, on average, more than 1.5 inches taller than the sprinters, but nonetheless had legs that were a half-inch shorter. Longer trunks and shorter legs make for greater surface area in contact with the water, the equivalent of a longer hull on a canoe, a boon for moving along the water at high speed. Michael Phelps, at 6'4", reportedly buys pants with a 32-inch inseam, shorter than those worn by Hicham El Guerrouj, the Moroccan runner who is 5'9" and holds the world record in the mile. (Like other top swimmers, Phelps also has long arms and large hands and feet. That elongated body type can be indicative of a dangerous illness called Marfan syndrome. According to Phelps’s autobiography, Beneath the Surface, his unusual proportions led him to get checked annually for Marfan.)*
The more that elite sports markets have shifted from participatory affairs to events for bulging masses of spectators, the more rare the bodies required for success have become, and the greater the money needed to attract those rare bodies to a particular sport. 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 about forty and one hundred times the median full-time salary. In order to match a single year’s salary of the highest-paid athletes, an American man making the country’s median annual income for a full-time job would have to work for five hundred years.
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Genes affect body weight. The GIANT (Genetic Investigation of ANthropometric Traits) Consortium study of 100,000 adults found six DNA variants that influence heft. The FTO gene, in itself, accounts for several pounds in studies, possibly by influencing one’s taste for fatty foods. But, as anyone who has ever gorged himself on Thanksgiving dinner and then hopped on a scale can attest, weight is substantially affected by lifestyle.
Fat is the tissue in the body that is most responsive to training and diet. (And weight is extremely responsive to certain drugs. When Norton and Olds examined the inflating size of NFL defensive tackles, they found an eye-catching acceleration in size in the late 1960s and early ’70s, when steroids began to proliferate in football. From the 1940s to the 1990s, the body mass index of an NFL defensive tackle rose from 30 to 36. For a 6'2" tackle, that’s a rise in weight from 234 pounds to 280 pounds.)
Clearly, the FTO gene has been around since long before the recent obesity epidemic in the industrialized world. More genes that influence weight are sure to be found—studies of twins and adopted children suggest there are more out there—and the complex interplay of genetics, lifestyle, and weight are only beginning to be illuminated. Even combined, all of the DNA variants that the GIANT Consortium identified accounted for only a small fraction of bulk. (Based on my DNA analysis, I am entitled to attribute just 8.5 of my 150 pounds to those genes.)
And just as an individual’s proportion of fast- and slow-twitch muscle fibers influences his muscle growth potential, it also influences his fat-burning capacity. Researchers in the United States and Finland have independently shown that, while adults with a high proportion of fast-twitch fibers can pack on muscle, they have a more difficult time losing fat. Fat is primarily burned as part of the energy-making process that occurs in slow-twitch muscle fibers. The fewer slow-twitch muscle fibers an individual has, the lower his capacity to burn fat—one possible reason that sprint and power athletes tend to be stockier than endurance athletes, even before and after their competitive years.
And while it is obvious that diet and training can dramatically alter an athlete’s build, there are limits. Limits delineated by an individual’s skeleton.
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Francis Holway, an exercise and nutrition researcher in Buenos Aires, has been obsessed with the limits of body types since childhood. His first inspiration was the story of Tarzan. He was fascinated by how the son of a British lord adopted by apes and transplanted to a jungle environment could develop the rhino-wrestling physique and vine-swinging skills to thrive. Holway’s first experiments, at the age of seven, came when he would gulp down spoonfuls of oatmeal and then flex his biceps right after the meal to see if they had grown.
As a kid, he first thought that the sport shaped the body; that basketball players would grow tall from playing and weight lifters would become squat from squatting. To some degree, the research he has conducted as an adult has borne out similarly startling phenomena. Holway measured the forearms of a group of tennis players ranked in the top twenty in the world and found that their racket arms grew slightly differently from their nonracket arms. The racket-side forearm bones of the players grew around a quarter-inch longer than the forearm bone of the nonracket arm. And the elbow joint widened a centimeter. Like muscle, bone responds to exercise. Even nonathletes tend to have more bone in the arm they write with simply because they use it more, so the bone becomes stronger and capable of supporting more muscle. “It’s just amazing how the bones can adapt to repeated stress,” Holway says. Those tennis pros literally served and volleyed their ways to longer forearms. And yet, this malleability is limited.
Libby Cowgill, an anthropologist at the University of Missouri, has studied skeletons from around the world in an effort to determine whether certain populations have built strong skeletons through childhood activity or whether they are simply born with robust skeletal scaffoldings capable of supporting mounds of muscle. “We can see differences in the strength of bones in different populations already at one year of age,” Cowgill says. “What I’ve found indicates that these differences are just there. They are exacerbated over the course of growth based on what you’re doing, but it looks like people are born with genetic propensities to be strong or to be weak.”
In one study, she compared the skeletons of Mistihalj people—a group of medieval Yugoslavian herders—to the skeletons of kids from 1950s Denver. “The herders’ kids are the biggest, buffest kids I’ve ever seen,” she says. “Based on data of modern American children, we’re just puny in terms of the amount of bone we have.” But might a strict childhood training program be able to transform any American tot into a mighty medieval herder? “There’s a lot you can do with activity, and especially starting it earlier,” Cowgill says. “But it’s looking more and more like there’s a genetic component as well.”
The skeleton you are bequeathed has a lot to do with whether you will ever be able to make the weight required for a particular sport. Holway compares the skeleton to an empty bookcase. One bookcase that is four inches wider than another will weigh only slightly more. But fill both cases with books and suddenly the little bit of extra width on the broader bookcase translates to a considerable amount of weight. Such is the case with the human skeleton. In measurements of thousands of elite athletes from soccer to weight lifting, wrestling, boxing, judo, rugby, and more, Holway has found that each kilogram (2.2 pounds) of bone supports a maximum of five kilograms (11 pounds) of muscle. Five-to-one, then, is a general limit of the human muscle bookcase.*
“We’ve had people come in for consultation and they want to increase their muscle mass for aesthetic reasons,” Holway says. “We measure them, and if they’re close to five-to-one we ask them how long they’ve been at this same level of development or strength. They’ll say for the last five years or seven years, and they haven’t been able to surpass it.” Holway experimented on himself, spending years in heavy weight training with a diet high in protein and supplemented by creatine. But as he closed in on five-to-one, inhaling more steaks and shakes only added fat, not muscle.
Male Olympic strength athletes whom Holway has measured, like discus throwers and shot putters, have skeletons that are only about 6.5 pounds heavier than those of average men, but that translates to more than 30 pounds of extra muscle that they can carry with the proper training. Holway uses his measurements to help tailor athletes’ training. In the shot put, for example, an athlete needn’t move himself very far, so even adding extra fat might be worthwhile, since the athlete needs to pack on bulk to become relatively more massive than the object being thrown. But in javelin, where the athlete needs to both run fast and throw hard, he should be wary of trying to add weight beyond the five-to-one ratio, as it will likely be fat. Or consider a Sumo wrestler, or an offensive lineman in football who simply wants to be difficult for his opponent to move. He might do well to add extra fat. Offensive linemen are incredibly strong, but they most certainly are not ripped.
Again, when innate biological differences are taken into account, it becomes clear that successful training plans are those tailored to the individual’s physiology. As Dr. J. M. Tanner, an eminent growth expert (and world-class hurdler), wrote in Fetus into Man: “Everyone has a different genotype. Therefore, for optimal development, everyone should have a different environment.”
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Heaving sports performance to untouched heights requires both specialized training and specialized bodies to be trained.
Today, the expanding universe of athletic body types is slowing down. Much of the self-sorting, or artificial selection, is finished. The tall athletes are no longer getting taller compared with the rest of humanity at the rate they were two decades ago, nor the small smaller. And the march of constantly shattered world records is slowing right along with it.
Over most of the twentieth century, the adage “records were made to be broken” rang chronically true. But athletic records in most, but certainly not all, events that have high historical participation are now inching forward—if, that is, they are moving forward at all. The coveted world records in the men’s mile and 1,500-meters (the race close to the mile that is run outside the United States) were broken collectively about eight times per decade from the 1950s to 2000, but not at all since. Other records have continued to creep down, but usually by small margins. It will be intriguing to see whether the financial success of Usain Bolt, who dropped records by rather large margins, draws more athletes with his unusual combination of explosiveness and height away from other sports to sprinting.
“There are still some unexploited parts of the world, but we’ve reached much of the global market,” says Tim Olds, one of the Big Bang of body types scientists. “We’re getting closer to reaching the limit of our source populations for bodies. Population progression is slowing globally, so we’re going to see slowing growth in both body size and body shapes, and in records as well.” Just as exploring the earth must once have seemed like an endless endeavor for adventurers, perhaps the era of constant record shattering is largely in the past, and the future will be one of baby steps forward.
As the expanding universe of sports physiques has sped outward, finding those increasingly rare bodies has fostered an increasingly extensive, and expensive, global talent search.
In that endeavor, no league has been more successful than the National Basketball Association.
Today, literally billions of customers have a ticket to the Olympics, the World Cup, or the Super Bowl with the flick of a remote control. As a result, most sports enthusiasts are now spectators to the elite as opposed to participants in the comparatively quotidian, a huge population of recliner-bound quarterbacks paying to watch a tiny number of real QBs. That scenario creates what economist Robert H. Frank termed a “winner-take-all” market. As the customer base for viewing extraordinary athletic performances expanded, fame and financial rewards slanted toward the slim upper echelon of the performance pyramid. As those rewards have increased and become concentrated at the top level, the performers who win them have gotten faster, stronger, and more skilled.
A group of sports psychologists, particularly acolytes of the strict 10,000-hours school, have argued that improvements in individual sport world records and team sport skill levels have increased so vastly in the last century—faster than evolution could have significantly altered the gene pool—that the improvement must come down solely to increasing amounts of practice. As the rewards for top performers have grown, more athletes have undertaken greater quantities of practice in an attempt to earn them.
A portion of the improvements, though, even in straightforward athletic endeavors, are very clearly the result of technological enhancements. Biomechanical video analysis of legendary sprinter Jesse Owens, for example, has shown that his joints moved as fast in the 1930s as those of Carl Lewis in the 1980s, except Owens ran on cinder tracks that stole far more energy than the synthetic surfaces where Lewis set his records.
But technology is not the only source of improvement that is often overlooked. Undoubtedly, the increasing amount and precision of practice has helped push the frontiers of performance. But the winner-take-all effect, combined with a global marketplace that has allowed many more people to audition for the minuscule number of increasingly lucrative roster spots, has indeed altered the gene pool. Not the gene pool in all of humanity, but certainly the gene pool within elite sports.
•
In the mid-1990s, Australian sports scientists Kevin Norton and Tim Olds began compiling data on the body types of athletes to see whether there had been significant changes over the twentieth century. The sports science, after all, had changed drastically.
In the late nineteenth century, researchers of the science of body types—known as anthropometry—arrived at conclusions influenced by classical philosophy, like Plato’s concept of ideal forms; by art, such as Leonardo da Vinci’s Vitruvian Man, the famous depiction of a man’s body inscribed in a circle and square indicating the ideal human proportions; as well as by racially charged agendas. “There is a perfect form or type of man,” reads a late-nineteenth-century article enumerating the characteristics of an athlete, “and the tendency of the race [i.e. the white race] is to attain this type.”
At the time, anthropometrists felt that 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. So they asserted that the best athletes would have the most well-rounded, or average, physical builds. Not too tall or too small, neither too skinny nor too bulky, but rather a just-right Goldilocks-porridge version of a man. (And it was only men.) That was the belief for any sport: the average human form would be ideal for all athletic pursuits. This confluence of subjective theory and philosophy dominated the agenda for coaches and physical education instructors in the early twentieth century, and it showed in athletes’ bodies. In 1925, an average elite volleyball player and discus thrower were the same size, as were a world-class high jumper and shot putter.
But, as Norton and Olds saw, as winner-take-all markets emerged, the early-twentieth-century paradigm of the singular, perfect athletic body faded in favor of more rare and highly specialized bodies that fit like finches’ beaks into their athletic niches. When Norton and Olds plotted the heights and weights of modern world-class high jumpers and shot putters, they saw that the athletes had become stunningly dissimilar. The average elite shot putter is now 2.5 inches taller and 130 pounds heavier than the average international high jumper.
On a height-versus-weight graph, the duo plotted the average physiques of elite athletes in two dozen sports; one data point for the average build of an athlete in each sport in 1925, and another for the average build of an athlete in that same sport seventy years later.
When they connected the dots from 1925 to the present for each sport, a distinct pattern appeared. Early in the twentieth century, the top athletes from every sport clustered around that “average” physique that coaches once favored and were grouped in a relatively tight nucleus on the graph, but they had since blasted apart in all directions. The graph looked like the charts that astronomers constructed to show the movement of galaxies away from one another in our expanding universe. Hence, Norton and Olds called it the Big Bang of body types.
Just as the galaxies are hurtling apart, so are the body types required for success in a given sport speeding away from one another toward their respective highly specialized and lonely corners of the athletic physique universe. Compared with all of humanity, elite distance runners are getting shorter. So are athletes who have to rotate in the air—divers, figure skaters, and gymnasts. In the last thirty years, elite female gymnasts have shrunk from 5'3" on average to 4'9". Simultaneously, volleyball players, rowers, and football players are getting larger. (In most sports, height is prized. At the 1972 and ’76 Olympics, women at least 5'11" were 191 times more likely to make an Olympic final than women under five feet.) The world of pro sports has become a laboratory experiment for extreme self-sorting, or artificial selection, as Norton and Olds call it, as opposed to natural selection.
Big Bang data in hand, Norton and Olds devised a measure they called the bivariate overlap zone (BOZ). It gives the probability that a person randomly selected from the general public has a physique that could possibly fit into a given sport at the elite level. Not surprisingly, as winner-take-all markets have driven the Big Bang of body types, the genes required for any given athletic niche have become more rare, and the BOZ for most sports has decreased profoundly. About 28 percent of men now have the height and weight combination that could fit in with professional soccer players; 23 percent with elite sprinters; 15 percent with professional hockey players; and 9.5 percent with Rugby Union forwards.
In the NFL, one extra centimeter of height or 6.5 extra pounds on average translates into about $45,000 of extra income. (Particular professions that require unique physiques have an even more concentrated winner-take-all structure and outdo even professional sports. The BOZ for regional catwalk models is less than 8 percent, dropping to 5 percent for international models, and to just 0.5 percent for supermodels.)
And the Big Bang of body types goes down to the body-part level as well. While tall athletes have grown taller at a much faster rate than humanity as a whole, and small athletes have shrunk relatively smaller, athletes in certain sports have increasingly needed extremely specialized body traits. Measurements of elite Croatian water polo players from 1980 to 1998 show that over two decades the players’ arm lengths increased more than an inch, five times as much as those of the Croatian population during the same period. As performance requirements become stricter, only the athletes with the necessary physical structure consistently make the grade at the elite level. The shorter-armed athletes are more often weeded out.
In addition to having longer arms overall, the bone proportions in the arms of top water polo players have changed. Elite players now have longer lower arms compared with their total arm length than do normal people, giving them a more efficient throwing whip. The same is true of athletes who need long levers for powerful, repetitive strokes, like canoeists and kayakers. Conversely, elite weight lifters have increasingly shorter arms—and particularly shorter forearms—relative to their height than normal people, giving them a substantial leverage advantage for heaving weights overhead. One of the many failings of the NFL combine that tests prospective draft picks in physical measures is that arm length is not taken into account in the measure of strength. Bench press is much easier for men with shorter arms, but longer arms are better for everything on the actual football field. So a player who is drafted high because of his bench press strength may actually be getting a boost from the undesirable physical characteristic of short arms.
Top athletes in jumping sports—basketball, volleyball—now have short torsos and comparatively long legs, better for accelerating the lower limbs to get a more powerful liftoff. Professional boxers come in an array of shapes and sizes, but many have the combination of long arms and short legs, giving greater reach but a lower and more stable center of gravity.
The height of a sprinter is often critical to his best event. The world’s top competitors in the 60-meter sprint are almost always shorter than those in the 100-, 200-, and 400-meter sprints, because shorter legs and lower mass are advantageous for acceleration. (Short legs have a lower moment of inertia, which essentially means less resistance to starting to move.) Sprinters hit the highest top speeds in the 100- and 200-meter races, but the 60-meter race has a proportionally longer acceleration period. Perhaps the advantage of shortness for acceleration explains why NFL running backs and cornerbacks, who make their livings starting and stopping as quickly as possible, have gotten shorter on average over the last forty years, even while humanity has grown taller.
On occasion, technique changes in sports have changed the advantaged body types almost overnight. In 1968, Dick Fosbury unveiled his “Fosbury flop” method of high jump, which gives an advantage to athletes who have a high center of gravity. In just eight years after Fosbury’s innovation, the average height of elite high jumpers increased four inches.*
In other cases, body types have more nuanced effects. While smallness is generally a boon for endurance runners, Paula Radcliffe, the world record holder in the women’s marathon, at 5'8" is literally head and shoulders above most of her world-class competitors. It didn’t keep the iconically tough Brit from winning eight marathons in the prime of her career, 2002 to 2008. But Radcliffe’s size may have helped confine most of her victories to autumn. One reason that marathon runners tend to be diminutive is because small humans have a larger skin surface area compared with the volume of their body. The greater one’s surface area compared with volume, the better the human radiator and the more quickly the body unloads heat. (Hence, short, skinny people get cold more easily than tall, hefty people.) Heat dissipation is critical for endurance performance, because the central nervous system forces a slowdown or complete stop of effort when the body’s core temperature passes about 104 degrees.*
While Radcliffe in her prime was unbeatable on autumn mornings when races were held in cool temperatures, she was feckless in summer heat. At the Athens Olympics in 2004, when the marathon was held in 95-degree heat, despite having by far the fastest time coming into the race she was unable to finish and crumpled in a heap by the side of the road. The woman who won the race was 4'11". At the Beijing Olympic marathon in 2008, the temperature was 80 degrees and humid and Radcliffe finished a distant twenty-third. From 2002 to 2008, Radcliffe was 8-0 in marathons contested in cool or temperate conditions, and 0-2 and never even in contention in the sweltering summer Olympic races.
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Collecting data for the most famous study of athletic body types ever conducted took an international research team a full year and included 1,265 athletes who competed at the 1968 Mexico City Olympics, representing every sport (except equestrian) and 92 different countries. It took six more years for the results to be compiled and published in a 236-page book. Half the book is simply tables of body measurements. Even without text, they convey an obvious message: in most Olympic sports, athletes are generally more physically similar to one another than I am to my own brother.
Within track and field, most of the athletes could be pinned to an event simply by their body measurements. The men and women who raced the 400- and 800-meters or the high hurdles were the tallest of the runners—no surprise, given that the goal in hurdling is to clear the barriers with as little movement of the center of gravity as possible—while the marathoners were the shortest. No surprise there, either. But the similarities extended to less obvious physical traits of the skeleton.
Athletes in a sport or event tended to be similar in height and weight—and often different from a control population of nonathletes—and also with respect to the breadth of their pelvic bone and the skeletal structure of their shoulders.
Nonathlete women who were measured as a control group for the study had, of course, wider pelvic bones than nonathlete men. But female swimmers had more narrow pelvic bones than the normal, control population of men. And female divers had more narrow pelvic bones than the female swimmers. And female sprinters more narrow than the female divers. (Slim hips make for efficient running.) And female gymnasts had slimmer hips still.
Female sprinters had much longer legs than the control population of women, and about as long as the control men. Male sprinters were around two inches taller than the control men, and 100 percent of that was in their legs, such that when they were seated the sprinters were the same height as the control men.
The male swimmers were, on average, more than 1.5 inches taller than the sprinters, but nonetheless had legs that were a half-inch shorter. Longer trunks and shorter legs make for greater surface area in contact with the water, the equivalent of a longer hull on a canoe, a boon for moving along the water at high speed. Michael Phelps, at 6'4", reportedly buys pants with a 32-inch inseam, shorter than those worn by Hicham El Guerrouj, the Moroccan runner who is 5'9" and holds the world record in the mile. (Like other top swimmers, Phelps also has long arms and large hands and feet. That elongated body type can be indicative of a dangerous illness called Marfan syndrome. According to Phelps’s autobiography, Beneath the Surface, his unusual proportions led him to get checked annually for Marfan.)*
The more that elite sports markets have shifted from participatory affairs to events for bulging masses of spectators, the more rare the bodies required for success have become, and the greater the money needed to attract those rare bodies to a particular sport. 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 about forty and one hundred times the median full-time salary. In order to match a single year’s salary of the highest-paid athletes, an American man making the country’s median annual income for a full-time job would have to work for five hundred years.
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Genes affect body weight. The GIANT (Genetic Investigation of ANthropometric Traits) Consortium study of 100,000 adults found six DNA variants that influence heft. The FTO gene, in itself, accounts for several pounds in studies, possibly by influencing one’s taste for fatty foods. But, as anyone who has ever gorged himself on Thanksgiving dinner and then hopped on a scale can attest, weight is substantially affected by lifestyle.
Fat is the tissue in the body that is most responsive to training and diet. (And weight is extremely responsive to certain drugs. When Norton and Olds examined the inflating size of NFL defensive tackles, they found an eye-catching acceleration in size in the late 1960s and early ’70s, when steroids began to proliferate in football. From the 1940s to the 1990s, the body mass index of an NFL defensive tackle rose from 30 to 36. For a 6'2" tackle, that’s a rise in weight from 234 pounds to 280 pounds.)
Clearly, the FTO gene has been around since long before the recent obesity epidemic in the industrialized world. More genes that influence weight are sure to be found—studies of twins and adopted children suggest there are more out there—and the complex interplay of genetics, lifestyle, and weight are only beginning to be illuminated. Even combined, all of the DNA variants that the GIANT Consortium identified accounted for only a small fraction of bulk. (Based on my DNA analysis, I am entitled to attribute just 8.5 of my 150 pounds to those genes.)
And just as an individual’s proportion of fast- and slow-twitch muscle fibers influences his muscle growth potential, it also influences his fat-burning capacity. Researchers in the United States and Finland have independently shown that, while adults with a high proportion of fast-twitch fibers can pack on muscle, they have a more difficult time losing fat. Fat is primarily burned as part of the energy-making process that occurs in slow-twitch muscle fibers. The fewer slow-twitch muscle fibers an individual has, the lower his capacity to burn fat—one possible reason that sprint and power athletes tend to be stockier than endurance athletes, even before and after their competitive years.
And while it is obvious that diet and training can dramatically alter an athlete’s build, there are limits. Limits delineated by an individual’s skeleton.
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Francis Holway, an exercise and nutrition researcher in Buenos Aires, has been obsessed with the limits of body types since childhood. His first inspiration was the story of Tarzan. He was fascinated by how the son of a British lord adopted by apes and transplanted to a jungle environment could develop the rhino-wrestling physique and vine-swinging skills to thrive. Holway’s first experiments, at the age of seven, came when he would gulp down spoonfuls of oatmeal and then flex his biceps right after the meal to see if they had grown.
As a kid, he first thought that the sport shaped the body; that basketball players would grow tall from playing and weight lifters would become squat from squatting. To some degree, the research he has conducted as an adult has borne out similarly startling phenomena. Holway measured the forearms of a group of tennis players ranked in the top twenty in the world and found that their racket arms grew slightly differently from their nonracket arms. The racket-side forearm bones of the players grew around a quarter-inch longer than the forearm bone of the nonracket arm. And the elbow joint widened a centimeter. Like muscle, bone responds to exercise. Even nonathletes tend to have more bone in the arm they write with simply because they use it more, so the bone becomes stronger and capable of supporting more muscle. “It’s just amazing how the bones can adapt to repeated stress,” Holway says. Those tennis pros literally served and volleyed their ways to longer forearms. And yet, this malleability is limited.
Libby Cowgill, an anthropologist at the University of Missouri, has studied skeletons from around the world in an effort to determine whether certain populations have built strong skeletons through childhood activity or whether they are simply born with robust skeletal scaffoldings capable of supporting mounds of muscle. “We can see differences in the strength of bones in different populations already at one year of age,” Cowgill says. “What I’ve found indicates that these differences are just there. They are exacerbated over the course of growth based on what you’re doing, but it looks like people are born with genetic propensities to be strong or to be weak.”
In one study, she compared the skeletons of Mistihalj people—a group of medieval Yugoslavian herders—to the skeletons of kids from 1950s Denver. “The herders’ kids are the biggest, buffest kids I’ve ever seen,” she says. “Based on data of modern American children, we’re just puny in terms of the amount of bone we have.” But might a strict childhood training program be able to transform any American tot into a mighty medieval herder? “There’s a lot you can do with activity, and especially starting it earlier,” Cowgill says. “But it’s looking more and more like there’s a genetic component as well.”
The skeleton you are bequeathed has a lot to do with whether you will ever be able to make the weight required for a particular sport. Holway compares the skeleton to an empty bookcase. One bookcase that is four inches wider than another will weigh only slightly more. But fill both cases with books and suddenly the little bit of extra width on the broader bookcase translates to a considerable amount of weight. Such is the case with the human skeleton. In measurements of thousands of elite athletes from soccer to weight lifting, wrestling, boxing, judo, rugby, and more, Holway has found that each kilogram (2.2 pounds) of bone supports a maximum of five kilograms (11 pounds) of muscle. Five-to-one, then, is a general limit of the human muscle bookcase.*
“We’ve had people come in for consultation and they want to increase their muscle mass for aesthetic reasons,” Holway says. “We measure them, and if they’re close to five-to-one we ask them how long they’ve been at this same level of development or strength. They’ll say for the last five years or seven years, and they haven’t been able to surpass it.” Holway experimented on himself, spending years in heavy weight training with a diet high in protein and supplemented by creatine. But as he closed in on five-to-one, inhaling more steaks and shakes only added fat, not muscle.
Male Olympic strength athletes whom Holway has measured, like discus throwers and shot putters, have skeletons that are only about 6.5 pounds heavier than those of average men, but that translates to more than 30 pounds of extra muscle that they can carry with the proper training. Holway uses his measurements to help tailor athletes’ training. In the shot put, for example, an athlete needn’t move himself very far, so even adding extra fat might be worthwhile, since the athlete needs to pack on bulk to become relatively more massive than the object being thrown. But in javelin, where the athlete needs to both run fast and throw hard, he should be wary of trying to add weight beyond the five-to-one ratio, as it will likely be fat. Or consider a Sumo wrestler, or an offensive lineman in football who simply wants to be difficult for his opponent to move. He might do well to add extra fat. Offensive linemen are incredibly strong, but they most certainly are not ripped.
Again, when innate biological differences are taken into account, it becomes clear that successful training plans are those tailored to the individual’s physiology. As Dr. J. M. Tanner, an eminent growth expert (and world-class hurdler), wrote in Fetus into Man: “Everyone has a different genotype. Therefore, for optimal development, everyone should have a different environment.”
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Heaving sports performance to untouched heights requires both specialized training and specialized bodies to be trained.
Today, the expanding universe of athletic body types is slowing down. Much of the self-sorting, or artificial selection, is finished. The tall athletes are no longer getting taller compared with the rest of humanity at the rate they were two decades ago, nor the small smaller. And the march of constantly shattered world records is slowing right along with it.
Over most of the twentieth century, the adage “records were made to be broken” rang chronically true. But athletic records in most, but certainly not all, events that have high historical participation are now inching forward—if, that is, they are moving forward at all. The coveted world records in the men’s mile and 1,500-meters (the race close to the mile that is run outside the United States) were broken collectively about eight times per decade from the 1950s to 2000, but not at all since. Other records have continued to creep down, but usually by small margins. It will be intriguing to see whether the financial success of Usain Bolt, who dropped records by rather large margins, draws more athletes with his unusual combination of explosiveness and height away from other sports to sprinting.
“There are still some unexploited parts of the world, but we’ve reached much of the global market,” says Tim Olds, one of the Big Bang of body types scientists. “We’re getting closer to reaching the limit of our source populations for bodies. Population progression is slowing globally, so we’re going to see slowing growth in both body size and body shapes, and in records as well.” Just as exploring the earth must once have seemed like an endless endeavor for adventurers, perhaps the era of constant record shattering is largely in the past, and the future will be one of baby steps forward.
As the expanding universe of sports physiques has sped outward, finding those increasingly rare bodies has fostered an increasingly extensive, and expensive, global talent search.
In that endeavor, no league has been more successful than the National Basketball Association.
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