(caveat lector: I have never used the Daniels plan but use his calculator a lot and have run a few sub-3 marathons)

What does "at your limit" mean here for the MP workouts? Near your aerobic threshold? Near glycogen depletion at the end? Muscles almost giving way? Or mentally getting dark and unfocused / wanting to quit? I think the answer or answers tell you which workouts to prioritize.

If you were near threshold, emphasize the tempo runs to make sure MP is well in the aerobic zone. Near glycogen depletion or muscles giving out, make sure you do the long easy and MP runs and make sure your fueling strategy is giving you enough calories. Mentally getting dark, make sure your fueling is giving your brain enough sugar and make sure you reflect on your training successes as you taper to boost confidence, and keep the MP workouts for sure.

Notice that most of these answers probably mean the intervals aren't that important... but keeping some faster running in the form of strides or a few smooth 200s after a tempo run or on an easy day might help hone your running economy and form a bit.

17 w/12@ MP is a big workout and should give you a lot of confidence if you hit it (as it sounds like you did). My go-to indicator has been 20-21 with ~9 at MP (though the first 10 not super-easy), so longer overall but less at pace. Ideally on terrain similar to or harder than what you will race, and with everything else held as similar as possible. I was pretty destroyed after a workout like this around a year ago, and surpassed my marathon target a few weeks later. I think workouts like this are the best prep you can do, with the most specificity both physically and mentally.

Taper will definitely help make things a bit easier. Adrenaline cuts both ways and you need to watch that it doesn't make you go out too quick. Cooler weather than you've been training in is a huge boost if you get it.

Thanks for the reply.

"At my limit" probably refers to lack of energy/muscle strength/motivation but aerobically I still feel ok...at least I'm not breathing overly hard and HR is in zone 3 (maybe low zone 4 at times).

Ok, I'll focus on MP, long easy and tempo runs then and will try to keep weekly mileage up.

I have also booked in for a 3/4 marathon 3 weeks before the actual marathon...do you think I should run this at goal marathon pace or view it as a workout and do it as 10-12 easy with latter half at MP? I'm wary of ruining my recovery or taper by running it too hard but also would like to use it as an indicator of what I can run at on the big day.

That's great that you are feeling good aerobically after 12 miles at your goal pace; it sounds like a substantial part of the "at your limit" is mental.

I liked this article: https://lowellrunning.com/...penetrable-barriers/ -- which talks about the psychological barriers we set for ourselves based on past performance. Also very similar to how we mentally draw lines at BQ/3 hours/other arbitrary times, even if we are poised to smash through them.

A related follow-up question: how many marathons (if any) have you run before and what's your PR?

I would not suggest doing your 20-miler all at marathon pace 3 weeks out, that has a substantial chance of wrecking your taper which will hurt you both physically and (possibly more so) psychologically. It could go fine, but not worth risking your A-race on.

Much better to do 10-12 easy with 8 at marathon pace, maybe even building a little faster at the finish, rehearsing everything you need to do on marathon day (fueling, hydration, shoes, clothing as much as possible). 3 weeks out is great for a race or workout like that, especially in the race context for practicing not going out too fast and then picking up the pace later and reeling people in (that part should be fun!).

Great article - thanks for sending on. Definitely helps in not getting as worried about the goal pace.

This is my first marathon and first time trying to combine longer distance running with shorter distance (sprint and olympic distance) triathlon training, so some of my training has been trial and error...mileage definitely not as consistent as I had planned to be due to recovery needed from races as well as some taper weeks for races.

I ran a 1:28 HM in February but I know my running has significantly improved since then. That was after 2-3 months of base building slow running in the winter. After that HM I started tempo work and intervals in preparation for sprint and olympic distance triathlons. Got my 5k down to 18:45 and I think I could probably run low 39 for 10k (haven't tested it in a while but ran a 40:20 as part of olympic distance tri).

Doing a HM next weekend and plan to go all out in it so that will be good indicator of where I'm at (although I don't plan to taper for it and I'm approaching it as a hard training session).

Understood on the advice around pacing for the 3/4 marathon...makes a lot of sense.

Will be interested to hear how the HM goes!

You are striving to do the difficult task of racing your first marathon, and don’t beat yourself up if it doesn’t go as planned. Most people take several attempts to figure out how to race a marathon, if they ever do it. Here, I’m distinguishing running a marathon to completion — which many people do at times much slower than their potential (usually involving a too-slow target time with even splits, or a reasonable target time but 10s of minutes lost in the second half) — from racing a marathon with nearly even splits at a time close to one’s current aerobic potential.

This is my first year of serious tri training and I actually think olympic and sprint distance races go well with marathon training; races are a hard effort running after an hour or two of other hard aerobic work, which is actually reasonably specific training for marathoning. Your fueling and general level of cardio exertion in an olympic tri are probably pretty similar to a marathon raced near your potential. Of course in a marathon you have to do it all on your feet and the cumulative impact and/or glycogen depletion from using the same muscles for 3 hours can be much harder, and generally requires far more recovery time (~ a month if you really go to the well).