i ran a 1:20 half last fall. what should my goal be for a marathon in may?

Depends on the course of the half and the full, plus how much you can improve your training. I'd guess anywhere from 2:50-3:00.

Double the half marathon time, then add nine minutes, to determine rough time equivalence. For you that is 2:49ish. Smart to run a half leading up to a marathon anyway, so that time will be an even more useful x for 2x + 9, because it will be closer to the race. Your goal will also depend on what degree you are stronger or weaker in fitness on race day compared to when you ran the 1:20. Read some about training to acclimate yourself to running past two hours. It’s not just that 26.2 miles is further, but that the third hour takes some getting used to (and preparation on race day) in order to avoid or lessen cramping in the later miles.

Useful Formula wrote:

Double the half marathon time, then add nine minutes, to determine rough time equivalence. For you that is 2:49ish. Smart to run a half leading up to a marathon anyway, so that time will be an even more useful x for 2x + 9, because it will be closer to the race. Your goal will also depend on what degree you are stronger or weaker in fitness on race day compared to when you ran the 1:20. Read some about training to acclimate yourself to running past two hours. It’s not just that 26.2 miles is further, but that the third hour takes some getting used to (and preparation on race day) in order to avoid or lessen cramping in the later miles.

Agreed. That formula is pretty accurate, especially for half marathon times of 1:30 or less. And also agree, depends how your running fitness has progressed since the 1:20. You could potentially be looking at a 2:42-2:45 if all has been going exceptionally well. I dropped my half marathon time from 1:23:30 to 1:15:50 over the course of 4 months. Biggest change I made was consistently training 7 days per week including X3 10 mile tempo runs per week with a group of fitter runners who helped raise my fitness by pulling me through some of the tougher sessions and increasing my overall mileage from 60 to 90 miles per week.

I'd just like to emphasize, training with a group of runners who are substantially fitter than you is something that I think a lot of people overlook when it it comes to trying to bust through plateaus and/or raise your fitness beyond what you thought you were capable of.

2:40

2:19

2:50-2:55 should be the goal. All depending on if you get your long runs in consistently (25km). Training for a 1.20 half can be done on lower mileage, so up it and up the tempo runs (6-8km once a week would be good, maybe some 2x4, 2x5km).

theRanMan wrote:

2:50-2:55 should be the goal. All depending on if you get your long runs in consistently (25km). Training for a 1.20 half can be done on lower mileage, so up it and up the tempo runs (6-8km once a week would be good, maybe some 2x4, 2x5km).

that being said I think your mileage is good enough for 2:50...And maybe even better.

Sub-2:50.

aa aa aa dd wrote:

ran the half off of 60mpw. will peak this spring at 70-80 mpw. what should my goal be for the marathon?

Based on the amount of information you have given about your training and running history my estimate would be:

2:30 - 4:30 / or DNF

theRanMan wrote:

2:50-2:55 should be the goal. All depending on if you get your long runs in consistently (25km). Training for a 1.20 half can be done on lower mileage, so up it and up the tempo runs (6-8km once a week would be good, maybe some 2x4, 2x5km).

This looks right to me. When I was running 1:18s for the half I ran a 2:54 marathon, and that was on about 40-50mpw, not the really good 60-70mpw that the OP describes.

Agree with doubling your half time and adding about 9 minutes, if, you build adequate endurance for the marathon, with enough long runs, overall mileage and workouts.

(Half x 2) + 9 minutes, assuming proper marathon (not half marathon) training.

GreatDane1 wrote:

I'd just like to emphasize, training with a group of runners who are substantially fitter than you is something that I think a lot of people overlook when it it comes to trying to bust through plateaus and/or raise your fitness beyond what you thought you were capable of.

When I started finishing first in mostof our club's Thurs. 8.5 mile hill run I said I was gonna have t o find a new club unless those guys picked it up. ((I was kidding of course, but not entirely.

You always want to get into an orchestra where there are players you can rise to.

I ran a 1:18:50 HM and followed it up with a 2:51:17 marathon, both on flat courses.

You know what’s really predictive? 10 x 880 with a quarter jog. If you can average 2:50, you can look forward to a 250-51 marathon given a min 70 miles a week. It used to be my favorite workout along with 6 repeat miles with a qtr jog.

Anyway good luck!

If you’ve been training consistently since that time, your half time might be 1:15 or faster. I’d say around 2:37-2:40.

Sub 2:45, assuming you do increase your mileage, add in some quality 20+ mile long runs, and include some Pure Hate in your training.

It really depends on how hard you train and when in May. If you have 3 solid months to train and are upping your weekly mileage I don't see why you can't improve upon your 1:20 half to do even better than the predicted 2:49 / 2:50 marathon.

I've only run one marathon a long time ago but in 2019 was able to move my half from 1:36 to 1:24 in 3.5 months of training and I topped out at 50 mpw. Everyone is different but I think that you are starting from a great place and as long as you stay healthy and injury free you should be able to improve 10% in the next 3 months and for that reason I'd target a 2:39 goal, maybe try and run the first 13.1 at 1:20 pace and depending on how you feel adjust.

Also how did you feel after you ran a 1:20 half? If you felt good then that is even better you probably would improve with your existing mileage.

Even if 1:20 proves a little fast for the first half f your marathon it isn't likely to derail your race, let's say you do a 1:20 / 1:30 split you are still at predicted pace based upon your half but I'm pretty confident you will have a 2:40 or better race in you if your training continues to pick-up and you push yourself.

aa aa aa dd wrote:

ran the half off of 60mpw. will peak this spring at 70-80 mpw. what should my goal be for the marathon?

The reach goal should be to break 2:50, but you don't want to blow up and run over 3 hr, because the 3-hr marathon is a wonderful lifelong goal for so many people, and you never know if you will be in that shape again. There is something magical about having a marathon PB that starts with a 2. So you don't want to blow a chance at breaking 3 by going out too fast. If I were you I'd go out in 2:51 - 2:55, marathon pace and try to negative split.