Base mileage is utter crap (For me
) For my body to react and change I need to inflict some pain. Hill Sprints anyone?
I would bet it isn't necessarily that base mileage is crap for you, I'd bet it is the overall training composition when you include more base mileage that slows your progress. Training composition is the key to making progress, not individual sessions. Although it could also be your understanding of base mileage that is the culprit
I always shunned low intensity work, determined to make as much pain as possible in a 6 hour training week, it worked to a degree, to the point I went from never raced to being in the top 15-20 in open time trial events with fields of 100+ riders, top 3 regularly in club events with fields of 30-40 riders and a good result in the National HC, i.e. went from nothing to fairly good in about 9 months of racing.
However since I started working with a coach, my training composition has changed a lot, even though many of the key sessions still remain in one guise or another, it still doesn't include much low intensity work, but has less overall time spent riding on the limit and I've only been outside the top 10 in one race this year and that was because I stood around taking my jacket off on the start line and set off 12 seconds late! Even with that penalty, I went over a minute faster than I ever had done in a 10 before and subtracting the penalty, it was a 30+ mph ride!
It is about knowing how hard to go, how long to go that hard and what to do when you aren't going hard!