What SHOULD a marathon feel like? Am I a total moron or am I incredibly wise?

Wait until mile 23 and then go for it. If you don't bonk, next time start at 22.

You might just be going out too hard based on your mileage and ability in long runs. Are you doing 3-5 20-milers in training, where you use no or limited water and GU? i think you should just go for it AFTER you figure out those last 5-6 miles.ME: 2:49 (30-35 mpw, first marathon) 2:35 (45 mpw, 2nd) 2:32 (50-60 mpw for about 4 months, 3rd)I’ve only run a three, but on my last one I knew I was going about it generally right because I trained exactly the same as my second. I see choosing your goal time as the most important part of running the race. If your goal is too optimistic or your mileage too low, you blow up severely. If it’s too conservative, you have something left at the end. I am a low mileage guy because that works for me, so I realize more miles can remedy some of this before someone chimes in, but it doesn’t work for my life/body.I try to be in a position at mile 20-21 to start working really hard just to maintain the goal pace. (i.e. If your goal race is 6:00 pace and you hit mile 20 right about 2 hrs, then the next 10k you really need to push just to maintain. Those last 6 will be hard almost regardless of pace, but I guess I’m saying it’s very unlikely you can run negative splits, so don't try to safely get to mile 20, try to walk the line to get there and then maintain until the end. look, if you hit mile 20 at exactly 6:00 pace you are NOT going to suddenly drop a 35:15 10k and run a 2 minute faster time. just won't happen. you need to chip those 120 seconds off gradually over 26 miles if that's your goal timepick the right pace based on your training. For me, it’s a hard HM race 4 weeks out followed by 10 easy, 10 at MP OR 4 w/u, 13-14 at goal pace, 4 c/d about 3 weeks out that really helps me determine my goal pace

During your planning and during the race treat mile 20 as the halfway point rather than mile 13. 20 and beyond is when mental toughness needs to kick in to overcome pain and fatigue.

That's actually a really good question. In my first 3 I either cramped or had to slow down a lot in the latter miles and ran huge positive splits.

In my last one I was very scared of that repeat, and ran conservatively, holding back a bit, even at mile 20 when I still felt good.

At mile 23-24 pace was starting to take a toll but I had some left, that I only let go at and after mile 25. Mile 26 was 6:21 and the last 0.4 of the race (on Garmin) at 5:52 pace.

Negative split of 1 min exactly for a 2:56 (6:44 overall). My goal was sub 3.

I wondered after the race if I left some time on the table, but I quickly disregarded that notion because that hypothetical doesn't matter. Running a negative split and holding some back until after mile 20-22 is perhaps sub-optimal but not completely unwise, leaving you with a great feeling after a strong finish.

Had I gone out harder I would either have chopped off another 45 seconds to 1:30 or...most likely, pushed a tad bit too hard, bonked or cramped, and call myself a moron!

Unless you're really really thin compared to your goal, or going for some kind of record, I'd rather risk leaving a few seconds off than blowing up by 5+ mins. Marathons are hard to recover from, and any "failure" sucks: you can't just re-lace up the very next week hoping to do better!

On the flip side, if you really want to optimize your pace, I'd recommend training with a heart rate ("HR") monitor.

Working out your LT and its neighborhood will really help determining what marathon pace feels like and where it should be.

For example if you manage to pinpoint your LT HR at 169 (via tempo intervals or other runs), then you'd know that 160-162 is quite close, and would be an aggresive pace to go out at in a marathon (but not finish at). And that going out at HR 152-154 would be conservative, while 156-158 closer to optimal.

It's not exact science, but I find that the marathon is an energy conservation vs. spending equation, and the closer you can get to an optimal trade off, the better you will perform. If you feel like playing around and testing things out a bit, a HR monitor can be very valuable.

I'm surprised it's rarely covered on letsrun. I get it that pure runners "just run, baby!" but it helped me out

try to maintain the pace what you can run in training at 85-87 % mhr. Leave the heartrate-monitor at home when running the marathon and run a even or almost negative split. And carbload properly. You will not bonk. It's not that difficult.

Ran a few too many wrote:

During your planning and during the race treat mile 20 as the halfway point rather than mile 13. 20 and beyond is when mental toughness needs to kick in to overcome pain and fatigue.

Yes, 20 miles is half way. That's bad math, but it's good marathon strategy. Begore a marathon I say that I'm going to race a 10k with a 20 mile warm up.