There’s an analogy I like to use to illustrate this point. Asking which is more important, genes or environments, is kind of like asking which is more important in making an ordinary automobile run, spark plugs or gasoline. You need both. They’re both absolutely essential, and it’s the same for genes and environments. Asking the question “which one is more important?” really doesn’t make any sense. Yet in spite of the fact that most people will tell you that genes and environments interact, they’ll also tell you that some characteristics are more genetic than others, even though this can’t be right. Research on epigenetics has really driven this point home. So, I think as we learn more about epigenetics, there will need to be some change in theoretical perspective among some scientists.
That’s as much a reflection on the fact that sports science hasn’t fully worked out what determines performance , and that performance is the result of a cluster of physiological, psychological and environmental traits that are currently too complex for us to analyse. Hard work and training is one of them, and when one looks at the very top level of performers, the difference made by hard work becomes the tiny difference between victory and defeat. But to tell people that they can achieve anything, regardless of their genes, seems to me to be misleading, when it is applied to sports like running and cycling.