I recently experimented with high mileage from May through July after being inspired by Bill Rodgers' book "Marathon Man". Last winter I upped my mileage from 60 to 70-75. Then in late April I did my first 90 mile week then just kept doing 90-95 mile weeks til mid June. Then the next 5 weeks I did 123-121-127-140-127 all at about a 730 pace average, with a hard 10 miler that 5th week at 617 pace. Then last week I did 2 20 mile days, a 17 mile day, then Thursday and Friday I did 8 and 5 respectively to freshen up for a 5k Saturday. I won the race leading from the gun, but there was no competition. I won in 17:44.8 with 2nd back in 19:22 and 3rd in 21:59. My 5k pr from last fall is 16:53 which I ran on 60 mpw. With body competition I bet I could've run 1710 or so 5k, but still that doesn't seem very good. Now I'm taking 2 weeks off to play things safe because my body feels like I could train maybe one or two more weeks without getting injured even though I got no injuries or nagging pains during the high mileage
This has made me question the value of high mileage. I don't think it helped me. I ran my best times on 60 mpw with lots of quality in my training. Now I'm wondering if high mileage runners run well because of the mileage or if they run well in spite of the mileage. Through my own personal experiences I'd have to say the latter. The mileage made me dislike running because it became annoying to have to run 90 minutes in the morning and then another 60 in the afternoon for 20 miles a day. I'm a fan of Bernard Lagat and Lawi Lalang, they run once a day and are among the best in the world because they don't do any junk mileage. Slow running just burns calories I think. Everything they do is fast and quality, and then they don't waste their time doing junk so they recover better and can maintain high quality in their training.
So overall, is high mileage overrated? Do we even need to increase our mileage past 60-70 mpw if we do it in singles and all quality?