>>110775
biology phd bert here, studies have tried to find alleles that improve athletic performance, but it's incredibly difficult because any given gene variant might be only found in a handful of athletes (or even just one), so you don't have the statistical power to make a significant finding; so, Tadej might have some allele that's just in his family that confers massive endurance capacity but because only he has it within the study pool, it won't pop out among all the other uncommon alleles that every individual has