Your personal running coach

How to Choose your Marathon Pace

6 weeks to London
5 weeks to Boston (soooo excited!) and Brighton
4 weeks to Manchester
3 weeks to Paris (sorry, much of this is a bit late for you!)

If you are preparing for one of the spring marathons, you will no doubt be trying to figure out your marathon pace this month. You’ve probably done a half marathon, and may even be applying the rough guide rule of double your half marathon + 20 minutes to figure out your potential marathon time.

Please note, for first time marathon runners, this is probably still too optimistic, unless you’ve been doing regular strength work, and you’ve missed less than 20% of your planned training.

Today’s article is about figuring out that marathon pace, and I’m writing it now, rather than at the start of April, because there are a few key workouts that will help you to determine an appropriate marathon pace to aim for.

1) The Half Marathon
2) Yasso 800s
3) The fast finish long run
4) The interspersed long run
5) The magic mile

Test 1: The Half Marathon

If you’ve done your build up half marathon, great! If its yet to come, then be cautious. A good estimate is to double your half marathon time and add 20 minutes. Or you could plug your half marathon time into this RACE CALCULATOR to come up with a likely marathon time.

When its accurate: – You’ve achieved 80% or more of your training plan. Its not your first marathon. You’ve done some strength training. You’ve run your half on tired legs.

When its not accurate: – This half marathon is your longest run yet and you had a 2 week taper for it. Your pacing for the half was attrocious. You got injured in the half and will not be able to complete any more long runs before the marathon* – this is why I say cautiously use this test if you are planning on racing a half marathon between now and your marathon; a 16+ mile training run is going to be more valuable at this stage than a half marathon.

*if this is the case and you’ve never run more than 16 miles, seriously consider deferring your marathon place, and have a very real run walk strategy that you will follow.

Test 2: Yasso 800s

The premise of this workout is that if you can run 8-10 repetitions of 800 metres, each taking you x minutes and y seconds, then you could complete a marathon in x hours and y minutes. Your rest period between intervals is as long as the interval:  For example, if you are running 3 minutes 20 seconds for 800m, you have 3 minutes and 20 seconds rest before beginning the next interval, and your predicted marathon time is 3 hours and 20 minutes.

When it’s accurate: – You’ve achieved 80% or more of your training plan, you are used to speed work, your paces are consistent from the first to the last interval.

When its not accurate: – You do all your training at a high intensity, you have never run further than 15 miles, you have never run a marathon, all your intervals were run on hilly terrain or you are doing a particularly undulating/hilly marathon.

This is a fun workout, and a great indicator of fitness, but it will over-estimate your marathon time if you are more suited/ used to speedwork, and it will under-estimate your marathon potential if you are un-used to speedwork.

Test 3: The Fast-finish Long run

If you’ve been following my blog for a while, you will have read the article published at the start of this year, 5 reasons why we do the long run slow. I stand by that article and those reasons, however, when you are getting close to the race, if you’re training has gone well, you can afford to break the rules in some of your long runs, to run a ‘fast-finish long run’.

The most challenging of these, and the best for predicting your marathon time is a 20 mile run, with the first 10 miles at easy pace and the last 10 miles at marathon pace. And its a good idea to use this as a race simulation run with appropriate nutrition strategies in place.
Caution: If you are wildly wrong about your estimated marathon pace, this run will truly knock your confidence, but if you are right, you will feel like Super Man

Well, my friend Tim- thanks for the picture.

Well, my friend Tim- thanks for the picture.

When its accurate: – This is probably the most accurate of all the tests discussed in this article, and I would say that if you hit the pacing on the final 10, you are within seconds of your accurate marathon pace. Even if the last 10 miles felt so diffucult that you can’t fathom running another 16 at that pace.

When its not accurate: – Umm… yeah, this test is pretty accurate

Test 4: The interspersed long run

This is very similar to test 3, and its almost as accurate. This is best for those who have never run a marathon, but are experienced enough to flit between paces well in a training run. The 10/10 strategy is a tough one, and it might be too difficult to manage, so instead, do a long run, with sections at marathon pace interspersed with sections at easy pace. Making sure that some of those marathon pace sections are in the last 5 miles of the run.

When its accurate: – Its going to be a little less accurate than test 3, but it is accurate as long as the marathon pace sections didn’t feel like you were racing a parkrun in between.

When its not accurate: – Less than 5 miles at Marathon pace, its probably not much of an indicator. Equally, if you did your final marathon pace, say at mile 16, but then didn’t manage to run the rest of the run (you had to walk), then the marathon pace you’ve picked is probably too fast.

Test 5: The magic mile

I’ve left this one until last, as its too late to use this one really. But, it is a great test when you are starting your next marathon training campaign.

Basically, after a lengthy warm up – probably 2 miles including some strides, run a mile, either on the track or on a very flat terrain, then have a lengthy cool down.

Take your time for that mile, multiply it by 1.3, (you will have to take it down into seconds to do the multiplication and then back up to minutes and seconds once done) and that is your likely fastest potential marathon pace in your next campaign, assuming you do the training. This test can be performed each month, and improvement monitored.

When its accurate: – When you follow one of the key I Run Success principles of consistency. My customers are trained for running year round, not just a few months into a key event. If you’ve basically done nothing for 2 months, there is not much credence to this test as your fitness will improve so much once you start.

When its not accurate: – Like the yasso 800s, if you are a speed demon, and have not got much endurance history, it is likely to overestimate your marathon time. Added to which, it gives you the upper limit of your potential.

So for all you spring marathon runners out there, here are some tests that can help you choose your likely marathon time, check out next week’s blog for a bit about actually pacing your marathon race.

And if you want to make sure you receive all the latest updates from I Run Success, subscribe to our mailing list here, and get a free Marathon Nutrition Guide.

Get the free video series

Subscribe to get the latest video straight to your inbox

Powered by ConvertKit
Angela Isherwood

Angela Isherwood is the founder of I Run Success
She is a REPs Level 3 Personal Trainer, a Run England Running coach, and a multiple marathon runner. She is a London Marathon Good for Age runner, a Boston Marathon Qualifier, a parkrun Run Director and Trainer for Goodgym Colchester.

Leave a comment