Sub-3 wrote:
for arguments sake well say average is 15:00 5k, 31:00 10k during college career. Runs 30-40mpw now. several years removed from college training. spent those 4 years will on/off training.
disclaimer**this is fabricated so times may not be realistic
I think most of those runners could run sub 3 in a marathon, provided they did a few 20 milers leading up to the marathon. If they didn't do a few long runs like that, I'd say maybe 30 to 40% would still go under 3.
I had a teammate in college who was slightly slower than those times you listed. He was constantly injured, so finally gave up on really training for running. After college, he decided to do a marathon. Since he knew there was no way he could handle the training, he instead did 90m to 2hr bike rides daily, with two weekly runs, one of 7 or 8 miles, the other of 15 to 20 miles. He did this for three months leading up to his first marathon and ran 2:48. But that isn't quite "no marathon specific training," since his long runs were obviously geared towards the marathon, although some elite 10k runners do long runs that long.