Ross Tucker at SoS has a couple of very well-argued, IMO, posts on the role of genetics vs. training in performance (he discusses both athletic performance as well as other kinds, e.g., playing the violin). In the earlier post he criticizes the notion, argued among others by popular writer Malcolm Gladwell in his best seller Outliers, that practice is the major factor in performance. In that book, Gladwell popularized the notion that 10,000 hours is the critical level of practice required to become expert or elite in some discipline. Ross points out that the original study supporting this idea never examined whether there might be some individual variation in this number, and he then discusses some work that shows that there is indeed enormous variation—that some people reach expert level with far less practice hours than others. In fact, swimming sensation Michael Phelps, who made an Olympic final just four years after beginning to train seriously, seems to be an outstanding example. Ross also cites evidence that training of any length cannot account for even 50% of the proficiency in certain abilities studied.
So what else besides training is important? Obviously, genes. Ross notes that those who push the importance of training like to point out that no single gene has ever been shown to have much effect on athletic performance. But this is not because genes are not important, but because genetics is complex—even a seemingly simple physical trait like height turns out to have literally hundreds of thousands of genes contributing to it (Note: I am using “gene” loosely here; all human beings have the same genes, what distinguishes one individual from any other is the variants of these genes. For example, we all have the gene for citrate synthase, a key enzyme in aerobic metabolism, but there may be many different variants of this gene. Each variant results from a change or mutation in a single nucleotide base in the DNA coding for this gene—known as a single nucleotide polymorphism or SNP—and might result in an enzyme molecule with slightly different properties from those of another variant. SNPs are what DNA scans seek to identify, particularly those that may affect our susceptibility to certain diseases).
This enormous complexity frustrates attempts to use genetic tests to identify children who have exceptional ability in some sport or other activity at an early age. However, sometimes relatively few SNPs may make a major difference. Ross provides an example in discussing the evidence for differences in responders. He cites studies in which volunteers all underwent the same amount of training designed to raise their VO2 max. It turned out there was a huge range in the amount of VO2 increase, with those at one end of the spectrum only raising their VO2 max by 4%, while those at the other end raised it 40% with the same amount of training. Most individuals were somewhere in the middle.
Moreover, a set of 21 SNPs was identified which correlated with these differences. The high responders tended to have most of these 21 SNPs, while the low responders had fewer than half of them. An obvious conclusion is that elite athletes tend to be high responders to training. That is, in addition to having the right set of genes for high performance, their genes enable them to raise their base level much faster and further than the average.
Finally, to make this discussion more relevant to the Clinic (I tend to view the Clinic as the place to discuss all science in sport issues, even those not directly involving doping or other illicit practices), I will add that a study I cited here earlier (but don’t remember exactly where or when) suggested some variation in the response to EPO. It is a reasonable if yet unexamined hypothesis that there would be significant individual variation in the response to PES, just as there is variation in the response to training. This could pose another problem for the passport approach. It is possible, e.g., that two individuals who raise their HT by an equal amount would obtain significantly different power benefits, because of genetic (both direct and through training) differences in their ability to make use of the added oxygen. So not only could individuals respond differently to the same dose of a drug, but one might manifest a reduced spectrum of whatever physiological parameters are being used to detect the drug.
http://www.sportsscientists.com/
So what else besides training is important? Obviously, genes. Ross notes that those who push the importance of training like to point out that no single gene has ever been shown to have much effect on athletic performance. But this is not because genes are not important, but because genetics is complex—even a seemingly simple physical trait like height turns out to have literally hundreds of thousands of genes contributing to it (Note: I am using “gene” loosely here; all human beings have the same genes, what distinguishes one individual from any other is the variants of these genes. For example, we all have the gene for citrate synthase, a key enzyme in aerobic metabolism, but there may be many different variants of this gene. Each variant results from a change or mutation in a single nucleotide base in the DNA coding for this gene—known as a single nucleotide polymorphism or SNP—and might result in an enzyme molecule with slightly different properties from those of another variant. SNPs are what DNA scans seek to identify, particularly those that may affect our susceptibility to certain diseases).
This enormous complexity frustrates attempts to use genetic tests to identify children who have exceptional ability in some sport or other activity at an early age. However, sometimes relatively few SNPs may make a major difference. Ross provides an example in discussing the evidence for differences in responders. He cites studies in which volunteers all underwent the same amount of training designed to raise their VO2 max. It turned out there was a huge range in the amount of VO2 increase, with those at one end of the spectrum only raising their VO2 max by 4%, while those at the other end raised it 40% with the same amount of training. Most individuals were somewhere in the middle.
Moreover, a set of 21 SNPs was identified which correlated with these differences. The high responders tended to have most of these 21 SNPs, while the low responders had fewer than half of them. An obvious conclusion is that elite athletes tend to be high responders to training. That is, in addition to having the right set of genes for high performance, their genes enable them to raise their base level much faster and further than the average.
Finally, to make this discussion more relevant to the Clinic (I tend to view the Clinic as the place to discuss all science in sport issues, even those not directly involving doping or other illicit practices), I will add that a study I cited here earlier (but don’t remember exactly where or when) suggested some variation in the response to EPO. It is a reasonable if yet unexamined hypothesis that there would be significant individual variation in the response to PES, just as there is variation in the response to training. This could pose another problem for the passport approach. It is possible, e.g., that two individuals who raise their HT by an equal amount would obtain significantly different power benefits, because of genetic (both direct and through training) differences in their ability to make use of the added oxygen. So not only could individuals respond differently to the same dose of a drug, but one might manifest a reduced spectrum of whatever physiological parameters are being used to detect the drug.
http://www.sportsscientists.com/
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