“The broad truth is that nature and nurture are so interlaced in any realm of athletic performance that the answer is always: it’s both. But that is not a satisfactory end point in science. Scientists must ask, ‘How, specifically, might nature and nurture be at work here?’ and ‘How much does each contribute?’ In pursuit of answers to these questions, sports scientists have trundled into the era of modern genetic research.”
The above excerpt from the introduction of David Epstein’s The Sports Gene sums up and gives us a taster for the remainder of his uncompromising and thorough investigation into the role of genetics in elite athleticism.
Initially, Epstein pays respect to the powerful effect of repetition and practice in shaping performance outcomes and anticipatory skills. An example of such a skill is the ability of Major League Batters to predict the trajectory of a ball by taking visual cues from the pitcher before the ball is released, even though it is travelling faster than the visual system can track. After establishing the importance of practice in forming the ‘software’ of performance, the book dives into the innate, inherited ‘hardware’ of athleticism. The hardware, for example, that gives MLB batters greater than average visual acuity, allowing them to pick up anticipatory cues from a pitcher earlier.
Epstein covers a wide range of research on genetic markers associated with injury rates, explosive power, oxygen utilization, and pain tolerance, to name a few. Throughout the book, there are numerous examples of extremely fascinating and rare genetic variations that allow for extraordinary performances such as that of Finnish cross country skier Eero Mäntyranta. A mutation in a bone marrow gene gave Mäntyranta the genetic advantage of producing more oxygen-carrying hemoglobin than normal, helping him to win seven Olympic medals.
Epstein also profiles genetic variations that are found more commonly in athletes than the general population. One of these more common variations is the ACTN3 gene that codes for the production alpha-actinin-3, a fast-twitch muscle fiber gene also known as the “Sprint Gene”. The vast majority of sprinters from around the world carry the sprint variant while elite endurance athletes are more likely to have the variation that results in a non-functional ACTN3 gene. The absence of functional alpha-actinin-3 is thought to contribute to metabolic efficiency which may make the fast-twitch fibers of endurance athletes spare more energy during extended exercise.
Epstein explores the complex and wide-ranging nature of sports genetics in his book The Sports Gene. The take-home becomes increasingly clear: there is no one ideal training program and that individualization is essential. Personalized training plans responsive to an athlete’s genetics is not only the future of elite human performance, but also how we think about working smarter while we work hard.