> Or are you saying that Track programs should genetically test for this gene and drop whoever doesn't have it? They don't have to. There is almost certainly a

> Or are you saying that Track programs should genetically test for this gene and drop whoever doesn't have it? They don't have to. There is almost certainly a lot of self-selection going on. Anecdotally, I got one of those genetic kit tests done 10 years ago, and it included results on a "fast-twitch vs slow twitch muscle gene". I, who was a sprinter in high school who struggles immensely with long distance running, unsurprisingly have the gene for fast-twitch muscles. My wife, who has never participated in any kind of sport involving sprinting at any level but competes in long-distance races, unsurprisingly has the slow-twitch gene. Neither of us had any of these genetic tests available when we got involved in these activities. We just learned over time what we were naturally good at and what we struggled with. Does it mean that I can never run long-distance at the level my wife does, or that she could never have competed in sprinting? Maybe, but not necessarily. However if possible, it would take far, far more effort than sticking with the things we are good at. Between people gravitating to what comes naturally, and other filters (like making or being cut from a track or XC team), a lot of the genetic filtering already occurs without actual testing.