Hey Still,
Maybe this should be obvious, but what to you mean by "fatigue." Is it what Smoove called "a stretched thin" feeling? Do you mean that your legs never felt recovered from one workout to the next? Was it only legs or are we talking about a "yawning in the afternoon and looking forward to sleeping" overall fatigue? I'm curious for my obviously selfish reasons, but also because of an insight that I had yesterday that is, again, maybe pretty obvious to everyone else who uses Daniels.
I've mentioned in the past that I had been really "challenged" (to put it mildly) by using Daniels plans and the boards are littered with threads about how 2Q is difficult ("insane" I believe on one thread). Everyone has their ideas about how to modify the plan, but mostly the modifications are adjusting volume, either of the E runs overall, or the volume of work on certain Q days. But the other variable is, of course, your chosen VDOT.
Some people who don't have enough experience with the Daniels stuff might see the VDOT as a "given" rather than a "variable" because it is based on "a recent race performance." And then there are those who begin training at GOAL VDOT. And those who assume their 5k VDOT is equal to their marathon VDOT training paces. What I'm thinking is that, at the right VDOT, previously "insane" workouts might prove to be only slightly "nuts." But ultimately for most of us hobby joggers with race times all over the place, VDOT has to be chosen well in order for the training to be executable and effective.
Which brings me to your experience of running a cycle at a lower VDOT than your ultimate race VDOT. Given the spectacular results, it's not hard to look back and say your training paces were well chosen (as darkwave suggested). Maybe your fatigued body chose them instead of your ambitious mind, but consider the possible consequences if you had tried to train where your ambition placed you on the VDOT tables as opposed to what your body gave you. (Yes, I realize I'm sounding like too hot, here. I forget how he phrased it exactly, but after hearing it so many times in so many ways over so many years, too hot once expressed that idea in a way that made something click for me.)
These thoughts coalesced after running my Q2 yesterday while I was going through the data. Running by HR (what my body chooses for me), the pace is 2.5 VDOTS lower than what my ambition would have targeted (around 48.5 vs 51) (for both the M and T paces) according to that famous Daniels Training Tables Excel spreadsheet.
Instead of feeling depressed, I felt really pleased because the Q workouts both felt "right" whereas in the past my overly ambitious VDOT paces left me with that "insane" feeling. Now, I have only that "fatigued" feeling that I think I'm supposed to have.
So, that's probably just a long way of saying a lot of guys would probably benefit from dropping back a VDOT or two unless they're very certain that they've got it right. That's essentially what you, Still, ended up doing, with great results.
As I'm cooling down and taking it home yesterday, I was recalling a few of the Jack Daniels videos I saw on YouTube. He's a guy, not just a plan. I had this flash of understanding that if Coach Daniels had been my coach a few years ago when I tried to coach myself using his book, he would have been standing at the end of one of my reps with a smile and a laugh and saying, "Hey, slow the hell down." I was too much of a novice to know I was working wayyyy too hard. But I think he would have given me a "Good work, today" after both of this week's Q days.
I'm an entry-level Daniels user, so if anyone thinks I'm off on these observations, I'm willing to learn.