Originally Posted by
SClaraPokeman
Why would a mile runner do a 20 mile training run? I remember reading "The Perfect Mile" about the quest to achieve the first sub four minute mile. Roger Bannister was a medical student with very limited time. He would typically train at a track in St. James park (paying an admission fee!) and be done with his workouts in one hour. This involved intense interval work, but no LSD runs.
I'm not saying you're wrong, I just don't understand why doing training that doesn't mimic your event.
The short answer is that even a mile is an endurance event, so you need to build up your endurance. The long run is not so slow for elite runners, maybe 7:00 or 7:30 pace, so done in 2.5 hours. It's also only 20% of the weekly mileage. It's hard to do 100 or 150 miles a week doing track intervals.