I used to go to the track and practice this ... to consistenctly run MP lap after lap.  1st a 3-4 mile warm up and then 20-25K @ Marathon pace.  I would line up cupson the back of the benches just inside lane #1, so I could grab fluid on the run.  That was in 2005-2006 - I could rip off 50-60 laps all within 1-1.5 second delta from slowest to fastest.

I don't care that much anymore - I just show up to the marathon and run by feel.  If I could get back into PR shape, I might add a few of these again.

This is the single biggest thing I'm taking away from my first experience with Pfitzinger  as i trained for Sugarloaf. I still haven't figured out marathon pace in training runs. Pfitz calls for running at goal MP, not your current MP. I was apparently too aggressive with my goal and the MP work felt pretty hard. And, even after 3 marathons, I really don't know what MP effort should feel like. I'll keep experimenting I guess but goal MP pace/effort is the trickiest thing for me. And this Saturday I have 16 with 8 @ goal MP  -whatever that is. 

I've done Pfitzinger plans more than 10 times, and I still struggle with the MP workouts.

 Thanks for that. It makes me feel better. 

I know it's not good to look at just one aspect of training and think, "Ah-ha - that's why I missed my goal". But those were the hardest runs. Plus, I didn't get much space between MP and tempo pace until near the end of the training cycle. That's another clue that I was running the MP runs right at tempo pace. Probably too quick. 

I am trying to understand why you would run them at a goal marathon pace if the goal pace was that close to Tempo pace?.

Bingo, we have a winner. I was too aggressive in my marathon goal. Inexperience, Stupidity. At the time I figured goal MP would feel easier towards the end of the cycle. Which i guess sorta happened (tempo pace got a little quicker at the same effort too) but not enough to go out and run a 3:15. So I crashed trying. 

I run by feel, but keep a target pace range in mind. Then after the workout, try to assess whether I was running too hard for that pace. That's what I'm not very good at right now (but at least a little better than earlier this year). I guess there's no magic answer like, "goal MP should feel like_______".

I don't think I'd have the same issue with running current MP - it's when trying to run goal MP that figuring out the proper effort is tricky. hopefully it just comes with a bit more experience.

Could you clarify what you mean by "short mileage" here?  Do you mean an 8mi run at MP would but "just too hard"?   Clarification on the latter term would also be appreciated.  Do you mean, harder/just-as-hard as a tempo run?  Or do you mean "I'm above 'comfortably hard' and I shouldn't have to work that much for this workout to be beneficial?

I just plugged my 5k time into the McMillan calculator and it told me what my goal marathon pace was.    (I know, I'm an idiot)  I still haven't run a marathon that fast yet. 

I've plugged recent 10-20 mile races into McMillan and find the MP that comes out is usually pretty close to what I end up running. So, that's what I'll target for MP and it usually feels just like MP. Also, it's a mental boost knowing you are training towards a realistic goal. Using a 5K time? Fugetaboutit!

I just plugged my 5k time into the McMillan calculator and it told me what my goal marathon pace was.    (I know, I'm an idiot)  I still haven't run a marathon that fast yet. 

Maybe you just need to run the 5ks a little slower?

Some pretty good stuff from Canova.