Adonis..............you are obviously well versed, but not very informed when it comes to athletics...........and you are probably a non-athlete (or never was an athlete). Your trying to tell us that the 2 single fastest humans on earth will not produce a fast off spring? They (the off spring) may not be eventual world record holders, but I would wager to say that they....with NO training, would be faster than 99.99% of the population. Marion Jones may/may not have taken performance enhancing drugs (I would say yes), but she was running world class times way back in high school! That's not attributed to good genetics? I understand your point....2 good gene pools does not always add up to greatness, but 2 SUPER ELITE athletes who have run faster than nearly any WORLD CLASS ATHLETE/SPRINTER in history...........are very,very most likely to have genetically-superior off spring.
Also.....as for the Manning's in football.....it's not genetics? Intelligence can be attributed to genetics (which they are) their both 6'5" 225 plus pounds....that's not genetics? No matter how much an individual trains, their not going to be 6'5" without certain gene traits. They won't run a 9.9 100 meters without superior genetics either....drugs or not. I have been an elite powerlifter who bench pressed 315 pounds as a sophomore in high school with relatively very little training, eventually pushing 400 as a senior at 200 pounds. Eventually, with 20 years of training I totalled internatonal elite in the USAPL (highest drug free ranking). My point..........my grandfather/father/mother had incredible genetics that they obviously passed down to me. Again..........not all produce superior off spring, genetically speaking.....but I would venture to say 2 SUPER ELITE athletes will produce something special.