© Getty Images The two Olympic marathons held last August in Beijing were literally races for the ages. Kenya's Samuel Wanjiru, then 21, broke more than an Olympic record with his 2:06:32 win; he crushed long-held conventional
). This turns on its head the accepted system of starting a marathon build-up from a low mileage base and building up the long runs and total miles between Christmas and the race – usually about 12 to 16 weeks. This is fine for relative beginners
