Run training by distance and setting PACE targets

Why not start off using the 1/2M 2:04 PR you have on McMillian?  You'll know if the pace is too hard based on your RPE when you run it.  They'll still be some over lap in the pace zones even at 4-5 min slower.

Since you appear to like the McMillan calculator, if I were in your shoes, I'd just do something like an all-out 5K or 10K on your own (depending on where you're at with your training right now) and use the result in the calculator.  It's hard to push yourself the way a race pushes you, but you can get close, I think.  If you have a fast friend, you could 'race' him or her for added incentive.

The field test that you describe is for determining HR zones, and will not (directly) give you a read on reasonable expected paces.

ETA:  ^^^^ What he said. (Beat me to it.) ^^^^^ 

Edited by Experior 2009-08-24 7:34 PM

Why?? I wanted to run a 3:30 at my last marathon, so I used McMillan to calculate paces for tempo, speed work, and long runs and using the F.I.R.S.T. program I managed a 3:33. Not quite what I wanted, but a 22 minute improvement over the previous year. I think I would have made it except I fell on some ice and got a nasty calf cramp.
If you got a 2:04 you can get sub 2:00

It is because the calculators are designed to provide a certain training stimulus with each of the paces.  The key is to run hard enough to target the specific training adaptation but not so hard that you are actually elicting a different adaptation (or just causing addiational fatigue).

If we consider Daniels VDot, he has the following paces:

E - easy, endurance pace (~z1-2)
M - marathon pace  (~z3)
T - threshold (~z4)
I - interval (~z5)
R - rep (>z5)

Now, if we take my 5km (18:50) as an example, this gives a VDot of 53 and if I were to do an I paced workout, I would aim to run a series of 1200's at 4:29.  The goal should be to run all repeats as close to this effort as possible as the goal is to stress VO2max during this workout. 

However, my goal over the next 12 months is to get below 18 for a 5km; if I used that to get my VDot (56) that would give 1200's at 4:18.  While this pace would likely still stress my VO2max, it provides no additional improvement to run this workout faster.

In fact, it is likely to result in a less benefical workout as I should be able to complete about 27' of total running on pace (6x4:29).  However, if I run the first 11 seconds faster, I will likely be struggling after the first couple of repeats and will likely fade as the workout progresses.  IME, it is likely that I would now only complete ~22' on pace as I complete only 5 of the 6 prescribed 1200's.

Shane