Confidence boost needed

Hi All,
New to the boards. Attempting first 100 Umstead 03/28; 2 dozen marathons, 6X 50Ks, 3X 50m over past five years. Running x 10 years.
Have been averaging 70mpw, two 50Ks in past 6 weeks-last weekend DNFed a 50m@mile 29-just gassed.
Question:Is this just a bad day, or should I scratch the 100?
The delta from a 31 to 100 is HUGE!
If I'm still a go for Umstead, any suggestions as to wherde to go from here? Back-to-backs vs solo long runs?

With your past running experience and recent training, I think a 100 miler would be no problem for you ... in fact, long overdue. With 100's there'll always be a huge gap between longest training run and the race itself, so that's not something to worry about. For some 100 mile training plans, 31 miles is the longest run. It's more about the pacing (slow!), nutrition and mental strategy (including missing sleep) more than anything. At 70 mpw and 2 50k's in last 6 weeks there's no question in my mind you're fully physically capable of it.

So the DNF could easily just be a bad day -- we all have 'em -- the bigger question (and my concern) is if the DNF is an indicator of over-training, or mounting fatigue. Did you "race" those two 50K's, and the attempted 50m? Or were you (hopefully) treating them more like long training runs? Burnout can easily happen, too.

Seems to me you could continue your training and 100-mile race plan but may want to focus more on rest and recovery from here versus pushing the limits -- basically maintaining what you've got. You already have a very solid mileage base and plenty of recent long run experiences. Of course I don't know your situation and your running ability ... but based on what you've said I'd just take precautions along those lines.

For long weekend runs, I'm partial to one long run followed by a shorter run, ie, 22 and 8, for instance. Then you have the best of both worlds: one continuous long run that would be longer than if you did a back-to-back, but also the experience of running on tired legs the next day. But people do it differently and if two shorter back-to-back runs make things easier on your body you might want to consider doing that from here until the race.

Forgot to mention: With just over 6 weeks left until the race, you're maybe a week away from the beginning of the traditional tapering anyway. So yeah, for sure take it easier from here. Your training is all but done. You'll be better off if you can conserve (and thus build) your energy from here via lower mileage, vs wearing it out by training a lot. Just my two cents.

Thanks so much for the reply.
The first 50K was a trail race that I ran fairly easily, but the 50K 3 weeks ago was on a road and I did probably go too aggressively on the back half, 4:43, so not super hard
Overall, I do not feel overly fatigued.

My plan was to do a 30/12-15 this weekend and see how that goes.
I'm luckily fairly durable and haven't had a significant injury in years (fingers crossed).

I'm an average runner, PR in past 18 mos 50K 4:29, marathon 3:23, Half 1:29, 10K 39:35, age 49.
thanks for any advice at all!
I feel much better already...

Well, maybe the 50m was just a bad day then. Seems like you're good to go as long as you're listening to your body.

It's funny how casually ultra runners throw out the term "average runner". A 3:23 marathon is BQ qualifying for you which means you're more like in the top 2% of runners nationwide, right?

Let us know how your race goes!