Human Limits

Exploring performance and health with Michael J. Joyner, M.D.

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Genetics of Elite Performance

Today, I want to do a little more on the genetics of elite athletic performance.  A couple of days ago I briefly reviewed the genetics of height.  The bottom line is that while 80% of height is heritable (runs in families); it has been very hard to figure out the genetics of height.  Hundreds of gene variants with very small effect sizes contribute to height and when all of these genes are considered the consensus among the statisticians is that somewhere between 5-20% of the variation in height can be explained by simply “reading” differences in the genetic code.

What happens if we zoom out and think about athletic ability in general and what makes an Olympian or even an Olympic champion?

1)   To be a champion at anything you have to practice, practice, practice and this has been popularized as the 10,000 hour rule by Malcolm Gladwell in his book Outliers.   10,000 hours is a debatable number but the idea of practice and commitment is not.

2)    Like height the genetic components that make up what might be called ‘talent’ have been really difficult to decipher.  How various gene variants that might give someone an edge in some element of the mental or physical aspects of a given sport remains mostly a mystery.  Jonatan Ruiz and colleagues have some ideas about the perfect genotype for endurance sports, and it is really rare.

3)    Remember the role of environment and culture.  Based on their success in distance running one would guess that the Kenyan and Ethiopian tribes that dominate distance running might also do well in cross country skiing and endurance cycling.  However, we will never know until it either starts to snow in East Africa or the roads there get good enough for cycling to take off.

4)    Success runs in families.  So does early exposure and access to coaching and perhaps a competitive environment at home.   Early exposure also starts in East Africa as young kids run to and from school and play soccer at high altitude all day long.

So, success in sports is multifactorial.   Ross Tucker and Malcolm Collins have come up with a model that explains how a bunch of these things might interact.  I don’t agree with every element of their model but it is a good start.   They also offer an excellent critique of the 10,000 hour concept.

Along these lines, in elite competition like the Olympics, the margin of victory is tiny and there is no way we can measure any variable in the lab accurately enough to predict who might win by less than 1%.   If you ask me for a rough guess I will tell you for most sports, 80% or more is about practice and commitment and that means that almost any young person has the physical ability to get really good at something (say breaking 3 hours for the marathon or becoming a low handicap golfer).  However, the closer you get to truly outstanding the more important that ill defined thing called talent is, and the less we understand about the genetics of it.

Finally, it is pretty clear that we are a long way away from a blood test to identify which child might do well at what.  Practical approaches like considering body size, measuring vertical jump, running various distances for time, tests of strength, and tests of coordination are probably a much better way to go.

Then there is the equally complex matter of the psychology of desire and commitment…..

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