The free weekly Sports Performance Bulletin published by Peak Performance from the United Kingdom has some excellent basic information about Performance and Ageing (The Brits spell aging with an "e"). Subscribe to their free email bulletin service and get the February 23, 2009 issue number 197. Peak Performance has ads and they offer to sell you all sorts of training information, but the basic bulletin is usually full of excellent information and the site has enough information on every topic imaginable that you cannot read it all.