Awhile ago, I read an interesting discussion in the USMS site about aerobic potential. The gist of it was that, other factors being equal, ones aerobic potential is limited by how late in life you begin participation in aerobic based sports such as swimming and running. The argument was that beginning ones 'career' after the onset of puberty puts you hopelessly behind peers who began theirs earlier in life due to the the effect of high levels of HGH during the onset of puberty and how it makes aerobic adaptation take place at a much faster pace than than in any other phase of a human's life.
For example, take a set of twins. Start one on a swimming, running, or cycling program say at about the age of 10. As for the other twin, don't let he/she participate in any aerobic based sport (baseball and football are OK) until they reach the age of 15, give or take. The theory says that no matter how hard or dedicated the latter twin trains after deciding to take up, say, cycling, that twin will never acieve the same level of performance as the first twin. Now this assumes that after puberty the first twin has been keeping up with at least a modest training program.
I wanted to pose this to members of this forum. Is this theory off the wall, or is there something scientific to it? I have seen some anecdotal evidence of the aforementioned phenomena, but I was wondering how seriously this question has been addressed.