It is funny how things go in cycles. It seems like it was about 10 years ago or so that I was reading a theory that most anybody could be trained to be an elite endurance athlete and that there really wasn’t a genetic limit to endurance sports performance. While many sports physiologists believed that some athletes “choose” the right parents, there hadn’t been a “endurance gene” found nor has there been one found since. Then in 2008 Malcolm Gladwell wrote the book Outliers, which is a good read if you haven’t check it out yet, which put forth the theory that it takes 10,000 hours of deliberate practice to make someone an expert in any given field (really this theory was first put forth by Professor Anders Ericsson). This theory was applied to everything from musicians, to business tycoons, to tennis and soccer players. It is a very compelling theory for many skills but I don’t think this theory really applies to endurance athletes, and more so to physiological adaptations.
Your parents and grandparents matter. Genetics, even though evidence is not proven, is most likely not absent from endurance sports performance potential*. While Taylor Phinney definitely had the early exposure and the means to ride early in life, he also had amazing world-class cyclists as parents. Just as tall parents give birth to tall kids, good endurance athletes (or potentially good) are most likely going to have good endurance athletes as kids.
Don’t think that your sporting destiny has been completely determined at birth though. Training still matters and performance is extremely complex. What has been shown in several studies is that an individual’s response to a specific training program can vary quite a bit. At least one study has made the claim that training response is about 50% dictated by your genes, the other 50% is determined by environment, lifestyle, financial, diet, and numerous other factors. Think about that, you can control a large portion of how your body responds to training despite who your parents were.
From my experience, while one athlete may not respond well to one specific training program they may excel at a completely different program. One of the reasons I continue to research other training methodology is not to find the holy grail of endurance sports performance, it is to add another tool to my toolbox. Some athletes respond better to a lot of volume, while others have much better results from shorter, more intense workouts. Just because the professional athletes in your discipline always do 25+ hours a week doesn’t mean that is what you should strive for in your own training. Do what improves performance! For example, there is a lot of research being done on using weight training for endurance athletes right now. While nothing is conclusive yet, I do know some very successful athletes and coaches who use strength training as part of their program and are getting very good results. Is it for everyone? Nope, but it may benefit some athletes.
So where does that leave the Nurture Vs. Nature death match? Probably at a draw (what is a draw in a death match? Do they both live or both die? Someone consult The Running Man for me…). I think it is safe to say that they both matter. Genetics most likely determines the “athletic ability” starting point and around half of your response to any given training stimulus. But it is our training, environment, and lifestyle that interact with those genes to get us to our true potential.