Long run before full marathon

When I did my marathon, I used Hal Higdon's training plan, and the final "really long run" was 20 miles. 

I'd say go for it!

I am looking about a month from now.  The last 2 weeks I have been doing the workout of the marathon group at my gym, rather than the half. 

I'd be comfortable to finish the half and could probably break 2:15.  For the full, I'd be looking at 5:00.

I might hold off until the spring for the full.

I say don't do the marathon.  Based on my math, you are doing 18 - 28 miles per week.  That's not nearly enough.  Yes, you may be able to get through it, but you don't have the base to make sure you can do it without injury. 

While training for a marathon, you should do several runs that are over the half marathon distance, usually bumping up from 14, 16, 18 and to 20 miles.  The half marathon distance should feel easy.  Even with this training, there is still a big difference between 20 and 26 miles. 

Sounds like you have a good base to train for a marathon, just not in a month.  There are so many marathons, don't rush and do this one.  There will be others and you can be much better prepared. 

35 - 40k a week?

Sure, that's a great starting point for marathon training ........ You should be peaking at 40+ miles a week to comfortably run one.

Could you finish?  Probably without any issues.  Would you enjoy the experience?  In my opinion, no.

I don't understand everyone's desire to rush into long distance stuff.  You've got plenty of time to build up to it and you will enjoy it more when you can comfortably know that you've trained enough for it.  Take your time, enjoy the 1/2 and set another longer goal for next year!

My first marathon, I kind of jumped in in the last minute due to being on a trip the week that the Napa marathon was held.  I did this off of a reasonably consistent 50 mpw schedule without any long runs.  I was able to get by in 3:29:xx, but it was the most painful experience I have ever had.  I learned to appreciate hydration and glycogen.  Your kind of flip sided.  Low miles with one long run.  If you recover reasonably well and can get 1-2 more long runs in you will be OK-probably less pain than me.  The long runs are key to a less painful marathon, the volume plus long runs are key to a fast one.  20 miles is long enough, but I would not be doing one on a single long run and low mileage. 

By the way, I would not trade that first marathon experience for the world, but knowing how it felt afterwards kept me away for awhile.

Why not?

You should reference the final time. If he is chasing to run in 6hrs, why not?

In running, everything depend on the pace you want to achieve.

We need his target time before judging

x2 great post

Actually, you shouldn't reference the final time.  His body is ready to properly run a half.  His body isn't ready to properly run a full.  He can have a good half marathon or a crappy full.  The choice seems fairly obvious.

Sure, if you want to risk injury and never run up to your potential, this is a great idea.

Also funny how this is a great post but you questioned my first one, being that they're saying basically the same thing.

Hehehehe .....

Maybe mine was just more "diplomatic?"

The ting that seems to be most convincing for doing just the half is body feedback, which is hard to argue with.

I have never run a race where I had to take walk breaks.  I know I can do the 1/2 straight, but a full is beyond that goal right now.

What realy resonated with me were the responses that pointed out I coul do a full, but at what cost?

Yeah, I am going to do the half.  Thanks for the feedback and for helping to clarify what was already in my head.

BT to the rescue again.

 Who said he is going to run? He is going to do a marathon. What if he walks and run and finishes in 6 hrs?

It was totally different

lol.  Clearly.

I see that it is difficult to understand.

Daremo  said he is going probably to finish and you were commenting that finishing can be an issue (in summary).

Is it the same? No

Is it clear now?

If my mother leaves my home tomorrow morning, probably tomorrow evening does 26miles.

This is the point I was highlighting.

There are a ton of plans out there for beginners and for people looking to just finish with a smile.  I would recommend Hal Higdon's beginner plan from www.halhigdon.com and while he has more aggressive plans, the beginner one has gotten many people through the run successfully.  I had a good friend and co-worker use it and I also paced him and he had a great run finishing right under his goal time.  You just have to make sure you follow the plan well and train in conditions and on routes as similar as you can to your planned race.

Good luck with it!!