Is it possible to teach an old dog new tricks?

Looking at the results of the SPMA SC Champs on the weekend, I am amazed. There were some outstanding times by people like Susan von der Lippe, Ande, Paul Smith, John Morales, Mike Shaffer and Jeff Farrel to name a few. (Sorry if I have left anyone out but not being from your part of the world and relatively new to this forum those are all the names that I recognise). Paul's times are just....WOW! 52.54 in 100 SCM free at age 48...let's just say that it is no mean feat. That would smoke a lot of 20 year old swimmers, let alone 40 year olds. He is living proof that life doesn't have to be boring at 40 - at least not slow. And Jeff Farrel's 28.21 world record for the 50 free is AWESOME at age 70. A HEARTY CONGRATULATIONS to all of you. So this has got me thinking. Everyday, people like these are expanding the limits of what we formerly believed possible for middle aged people. Dara Torres is another good example. And here is my question (or rather questions). Were all of these people elite swimmers before they turned Masters? Would you have to be an elite swimmer in your youth to achieve times like that in later life? Have these people established a huge aerobic base and lots of fast twitch muscle in their youths, without which times like these would not be possible in later life. What about swimmers who never achieved elite status in their youths? Would it be possible for them to achieve these times given the same training regimens? Or is it too late for them? Is it a bit like learning a language: the younger you are the easier it is. Or is it possible to teach an old dog new tricks? Syd