The Uncomfortable Science of Athletic Achievement.

by Kenneth W. Krause.

Kenneth W. Krause is a contributing editor and “Science Watch” columnist for the Skeptical Inquirer.  Formerly a contributing editor and books columnist for the Humanist, Kenneth contributes regularly to Skeptic as well.  He may be contacted at

No doubt older than documented history, the nature vs. nurture debate continues to perturb every intellectual nook and cranny of modern society.  The origins of intelligence, artistic prowess, beneficence, and antisocial proclivity remain popular and well-studied topics.  But nowhere does the conundrum’s obscurity haunt us with greater urgency than in the winner-take-all context of sport.

Athletic performance is surely influenced by genes.  But does DNA dominate the calculation so thoroughly as to render potential environmental factors like upbringing, education, passion, and perseverance all but irrelevant?  If so, why should we continue to reward our student, Olympic, and professional athletes, for example, with honors, extravagant riches, and adulation never truly earned?

In my experience as a trainer and generally active person, for what it’s worth, athletes at every common fitness level tend to credit their abilities and successes (or lack thereof) to either inherited trait or training, depending on which best validates their personal narratives.  In short, those who succeed attribute hard work or shrewd programming, while those who fail concede to innate limitation.

By contrast, as long-time sports writer David Epstein recently observed, “ignoring gifts as if they didn’t exist” is far more customary within the loftiest echelons of high-stakes sports (Epstein 2014). But why should that be true in contexts where extraordinary physical attributes are so starkly evident?

Perhaps elite athletes still train in the long shadow of pioneering research.  In the 1970s, for example, a graduate student at the University of Waterloo named Janet Starkes began to wonder why certain physical “hardware” often failed to explain expert performance. Consider reaction times, for instance.  Starkes knew that, contrary to popular intuition, both highly successful athletes and the general public require one fifth of a second to react to visual stimuli.

So in 1975 she invented the modern sports “occlusion” test.  Starkes asked competitive volleyball players to view numerous slides depicting game situations for only a small fraction of a second. The athletes were then instructed to judge in each instance whether a ball had been depicted in the frame.

At sixteen milliseconds, the flash was too rapid for anyone to actually recognize the ball or its absence.  But not only were the best players somehow able to identify it, they could glean enough extra information to know when and where the pictures were taken. After earning her Ph.D., Starkes continued occlusion testing at McMaster University and produced similar results working with the Canadian national field hockey team (Starkes 1987).

Expanding on her methods, Queensland researcher Bruce Abernathy equipped tennis players with goggles, and cricket batters with lenses, that turned opaque or blurred just before their opponents struck or threw the balls.  Similar to Starkes, he found that elite players needed less time (and less visual information) to accurately predict the play’s immediate future (Mann 2010).

After many sessions of practice, Abernathy concluded, elites are better able to “chunk,” or unconsciously group, critical bits of visual information into meaningful patterns. They can accurately predict, for example, whether balls would be returned to their forehands or backhands based only on the positions of their opponents’ wrists or elbows prior to contact with the ball.

Thus, many sports researchers have come to believe that exceptional skills are not innate to athletes, as “hardware” is to machines.  Rather, they conclude, such proficiencies are unconsciously acquired, or “downloaded,” like “software” after many hours of intense practice.

How many hours?  Some say about 10,000 will do the trick.  In 1993, psychologists led by K. Anders Ericsson—the now-famed “father of the 10,000 hour (or 10 year) rule”—analyzed data on three groups of violin students at the Music Academy of West Berlin (Ericsson 1993). Accumulated practice from age eight were tallied for likely international soloists (best of the best), probable symphony orchestra members (very good), and soon-to-be teachers (not so great).

Every violinist had dedicated an impressive 56 hours of general weekly practice to his or her craft, on average.  But the groups distinguished themselves in two important respects.  One, members of the top two groups spent about 24 hours per week in more intense solitary practice, compared to the would-be teachers’ nine.  Two, better students made an earlier start of it.  By age twelve, future soloists had topped future teachers by about 1000 hours of solitary practice.  By age 18, they had accrued, on average, 7410 hours relative to 5301 for orchestra members and 3420 for teachers.

Researchers later found that, regardless of instrument, expert musicians tended to accumulate about 10,000 hours of practice by the age of 20.  They also spent far more time engaged in grueling “deliberate” practice—usually solitary.  Quick to exploit any potential sound bite, the popular media extrapolated the 10,000 hour rule to cover any conceivable discipline, including sports performance.

Epstein, on the other hand, remains less impressed.  Ericsson’s seminal violin study, after all, included very few students each of which had already achieved much in his or her field.  “When most of humanity has already been screened out of a study before it begins,” says Epstein, “the study often has little or nothing to say about … innate talent.”  It should be noted as well that Ericsson himself never employed the term “10,000 hour rule.”  Indeed, he has since emphasized that the number represented only an average figure utterly incapable of predicting any individual’s potential.

By contrast, the genetic influence has been brightly illuminated by two interrelated aspects of modern culture.  First, technology has greatly expanded the customer base of big-time sports.  No longer reserved for the rich, the idle pastime of sports spectatorship now tempts anyone who can afford an electronic screen or a cheap ticket to a packed stadium.  Second, huge winner-take-all purses and their attending commercial opportunities have transformed the participant class as well, supplanting eye-of-the-tiger battlers with physical mutants more resembling comic book superheroes, villains, and even monsters.

During the early decades of the twentieth century, top sports coaches sought the fit average Joes because they believed that typical, well-rounded physiques were the ideal standard for all types of competition.  But as both audiences and incentives swelled, we had only to turn on our televisions to witness a profound anatomical renovation.

During the 1990s, Australian anthropometrists, Kevin Norton and Tim Olds, began collecting data from 1925 forward on athlete body types.  As the culture changed, they discovered, a “Big Bang” pattern of body types began to emerge (Norton 2001).  Elite sprinters, gymnasts, divers, and figure skaters got shorter, for example, while volleyball players, rowers, and football players got taller.

Norton and Olds soon developed the “bivariate overlap zone” measure, intended to predict the likelihood that a randomly chosen man or woman would possess a body minimally worthy of elite competition.  In terms of appropriate height and weight alone, BOZ analysis revealed that just 28 percent could play professional soccer, 15 percent professional hockey, and 9.5 percent as forward with the Rugby Union.  In the NFL, one more centimeter of height or 6.5 pounds of extra weight translated into $45,000 of additional income.

No doubt, the genetics of race affect sports performance too, though perhaps not as popularly imagined.  For instance, we know that certain Africans, or persons of recent African ancestry, do have an advantage based simply on the home continent’s greater genetic diversity.

Researchers have also discovered that an athlete’s geographic origins can help him or her get away with testosterone doping (Schulze 2008).  A common sports urine test measures a donor’s “T/E ratio,” or relative concentrations of both testosterone and epitestosterone.  Normally, doping upsets the typical one-to-one balance.  But cheaters who possess two copies of a particular version of the UGT2B17 gene will always pass.  Interestingly, a full two-thirds of Koreans, yet only ten percent of persons of European ancestry, meet that criterion.

By contrast, some athletes’ genes might make them appear as if doping, even when they are not. Take former Finnish cross-country skier, Eero Mantyranta, for example.  In the 1964 Winter Olympics, Eero won two golds and one silver medal.  In the 15K race, he won by an unprecedented forty seconds, and in the 30K, he bested his competition by over a minute.

At times during his career, Mantyranta was falsely accused of blood doping with a synthetic form of the erythropoietin hormone, or EPO, which signals the body to produce more red blood cells.  Indeed, Eero’s red blood cell count was often 65 percent higher than average.  More red blood cells, of course, means more oxygen-carrying hemoglobin, and an increased capacity for sustained exercise.

Geneticist Albert de la Chapelle decided years later to examine Mantyranta’s family tree.  Of ninety-seven relatives tested, twenty-nine had extremely high hemoglobin levels.  After much searching, genetic analyses finally revealed a single spelling change at position 6002 of the erythropoietin receptor gene, or EPOR for short, on the nineteenth chromosome.  This “stop codon” led the twenty-nine relatives’ bone marrow cells to naturally overproduce red blood cells.

This condition was passed down to Eero in autosomal dominant fashion, meaning that in this case only one copy of the mutated version was required.  Unsurprisingly, de la Chapelle could never convince Mantyranta of his biological advantage.  Eero argued to his dying day that his exceptional success sprang only from steely determination.

Of course any number of complex traits related to sports performance could be and probably are genetically influenced.  The philosophical determinist in me tends to believe that even discipline and desire—as well as the ability to quickly “chunk” information—are in fact products of genetic “hardware.”  But maybe that’s just my personal narrative seeking excuses for a lifetime of less-than-stellar athletic achievement.

In any case, some will take tremendous, if unwitting, comfort in the fact that we might never even draw near to a full understanding of the human genome.  And, as Epstein concedes, “humanity will continue to rely on chance and sports will continue to provide a splendid stage for the fantastic menagerie that is human biological diversity.”


De la Chapelle, A., Traskelin, A., and Juvonen, E. 1993. Truncated erythropoietin receptor causes dominantly inherited benign human erythrocytosis. Proc. Natl. Acad. Sci. USA 90: 4495-99.

Epstein, David, “The Sports Gene: Inside the Science of Extraordinary Athletic Performance.” (Current 2014).

Ericsson, K.A., Krampe, R.Th., & Tesch-Romer, C. (1993). The role of practice in the acquisition of expert performance. Psychol. Rev. 100(3): 363-406.

Mann, D.L., Abernathy, B., et. al. (2010) An event-related visual occlusion method for examining anticipatory skill in natural interceptive tasks. Behav. Res. Methods 42(2): 556-62.

Norton, K. and Olds, T. 2001. Morphological evolution of athletes over the 20th century: causes and consequences. Sports Medicine 31(11): 763-83.

Schulze, J.J., Lundmark, J., et. al. 2008. Doping test results dependent on genotype of uridine diphospho-glucuronosyl transferase 2B17, the major enzyme for testosterone glucuronidation. J. Clin. Endocrinol. & Metab. 93(7): 2500-06.

Starkes, J.L. (1987). Skill in field hockey: the nature of the cognitive advantage. J. of Sport Psychol. 9: 146-60.


One thought on “The Uncomfortable Science of Athletic Achievement.

  1. Brady

    I don’t know what the controversy is. When I have success, it’s because I worked for it. When everyone else gets the job done, it’s because they started with a genetic advantage.



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