Half Marathon to Full with 5 weeks between

I'm going to start off by assuming that you have never done a full marathon before.

I would  consider using the half marathon as a stepping stone to the full.  In other words, I would consider not really tapering, and adopting a full marathon training schedule to work towards that.  That would remove the taper and the off week from your plan.

On a side note.....If you have never done a full marathon before, why are you scheduling one so close to the half, and not giving yourself the appropriate amount of time to train properly for it?  Sure, you could pull it off, and I'm willing to bet that you will.  The question is, will it be worth it?  Your risk for injury, burn-out, or something else is going to increase in your scenario.  If you do go forward with this, I would definitely advise caution, and that you pay very close attention to what your body is telling you. 

Another vote for training for the marathon NOW... and just making that half a training run (not all out effort).

I don't think you shoudl go from a peak volume of 12.5 miles to a full marathon in 5 weeks.  It's too much too fast.  Rather, if you want 26.2 miles, you need to be upping your mileage now so you won't need to increase so much at the end.

Kudos for the ambition ... but I don't think it's a good idea. Let me put it this way: I've done four marathons and three marathon-length training runs, and there is no way I would do a half-to-full with a five-week bridge.

If you have an excessively compelling reason, one that to you is worth the potential injuries/illness that could a) keep you out of the marathon altogether [the reason could be bigger than the marathon itself?!] or b) put you out of training for months after ...

If you're committed, and this would be your first marathon ... respect the distance. You will be in for a very rude awakening during the marathon if your longest run is 15.5 miles. Ditto the sentiments on increasing your runs now, maybe even so that the half-marathon might in fact be less distance than a long run before it. Practice extreme self-control--if you're yanking the distance up more than 10%/week (not advised, but oh well) you must do the runs, including the half-mary, more slowly. And even more slowly than that if there's heat, hills, humidity, etc.

Not sure why a 13.1-mile training run, even at marathon pace (or faster), five weeks out from the marathon is such a bad idea. Please explain.

By my count, you have 14 weeks to the target marathon. I'm assuming if you've recently completed an Olympic , that you have a decent run base, not to mention adequate crosstraining. I see no reason why you can't train for the marathon and hit the half marathon five weeks out.

Oh, and my background includes fourteen marathons and countless 20+milers.

OMG--I actually provoked a response from the Bear. I don't care if it's good, bad or ugly ... I'm really honored.

As for assuming a good running base on a 6.2 mile Oly leg ... maybe, maybe not. Word in popular publications and forums has it that crosstraining is less helpful to running than is running as crosstraining for other pursuits.  

Why would I personally not do it? Well, unless I'd done a longer run before the 13.1 (which is probably not going to be the case with Susan), a 10% progression (not gospel, but not a bad idea either for a beginner to marathons) to the race would look like 13.1, 14.3, 15.7, 17.3, 19.0, marathon.

19-mile run the week before the marathon? I think not. Sure, there are ways to do a long-shorter alternation, but even exceeding the 10% over to 20% (just e.g., 13.1, 15.7,  8, 19.0, 9-12, marathon) looks pretty rough to me. Doable, but why? And that 7-mile leap to marathon is a beast. 

Why do you assume that the HM is going to be the longest run to date? I alternate my long runs with 13-14-mile runs on the weeks in between, so that I'll go 15, 13, 17, 13, 18, 13, 20, 13, 22, 13, 8 then marathon. Look at that, there's a HM four weeks before the marathon.

Fourteen weeks out doesn't allow that complete progression, but she could certainly get there without taxing herself.

Bear,

When you trained for your first half marathon, how many runs did you do longer than 13 miles leading up to it?

I agree that if she started training now for the marathon, she could do it.  But, if you go with the assumption of following the plan initially laid out, I don't think it would work well for a first-timer. 

My first Half marathon was a training run for my first marathon, so zero runs longer than 13.

Smart a$$.......

How close were the half and full? 

Probably ten weeks. But again, my premise is that her target HM doesn't have to be her first try at that distance.

I agree with your premise.

But if we have a different set of assumptions, things can change.