Just a short post. I'm reading Brad Hudson's book, Run Faster, which is awesome! For some reason, his book has gotten me to thinking about long, slow distance training, aka LSD, for ultras (which, by the way, is not the topic of his book). Everyone talks about the merits of specificity in training, and yet many ultra runners out there (like me) do tons of quality fast stuff when training for the 100-mile distance.
If you're training for a sub-3 hour marathon, then you need to run lots of miles at your goal pace, which is around 6:50. If you don't train a lot at goal pace, your body's not going to be ready for the demands of a hard 26.2 miles and you're likely going to fall short.
Looking at ultras, if your goal is 20 hours in a 100-miler, then that breaks down to 12-minute miles. With aid station and bathroom stops factored in, we'll say your running pace is around 11:30/mile (the other 30 seconds/mile is for the stops). So, in the name of specificity, doesn't it make sense to spend a lot of time training in that zone (10-11:30/mile)? If your goal is a 20-hour, does it make sense to run fast tempos and hammer it around a track, which don't equate to your ultra goal pace and only raise your injury risk?
I've always favored quality in my ultra training, but I continue to think about better ways to skin the cat that is the 100-mile distance, like tons and tons of miles near goal pace. This post isn't to suggest that quality for ultra training is bad; it might be the ticket. This post is just intended to express some thoughts I have and maybe get a dialogue going.