Running (and Walking) an IM Marathon (or just a Marathon)

Triathlete running in an Ironman
December 18, 2019

Simon Butterworth



I don’t always practice what I preach, but when it comes to how to run the marathon portion in an Ironman, I do.  At least I do these days.  And how I get it done is through planning for plenty of walking.  I have not been shy about advocating this approach as you may have seen in earlier articles or heard from me in person.   Unfortunately, many, like me, fought the idea that you could plan in walk breaks right from the start and still run fast.

Jeff Galloway proved you could finish a fast marathon at 70 while walking for almost 6 miles.  His qualifying time for Boston was 4:18, and if I remember correctly, Jeff ran around 4:10 (you need to go under the qualifying time these days to get in) using something like the following: 

Jeff has long been advocating a strategy like this. I personally started 10 years ago with the more obvious strategy of just walking through aide stations. To get down enough calories and fluids in the heat of Kona it was necessary to walk anyway.  That morphed to walking for 30 seconds halfway between each aide stations and then in 2017 I started to analyze what I was doing more closely.

What became obvious was that even with a shorter run interval, 2 min., I could not hold a good consistent pace for the 2 min.  The slowdown was apparent even in the early part of the marathon.  By 13 miles I was starting each run slower and slowing down even more over the 2 min. interval.  The other interesting thing was my recovery over 30 sec. was almost complete, respiration was almost “normal”, and HR down by 15-20%.  Next step was to try 90/30 sec.  With the shorter run I could start the run interval a bit faster but still as overall time progressed pace during the 90 sec. slowed too much, I thought, and 30 sec. walk was now clearly too long.  

A year ago, I went to 45/15 and this seemed to be the magic bullet.  In training I could hold my goal pace, a pace that would insure a very good IM finish, for my long runs (2-3 hrs).  At sea level in the right conditions (not Kona) I could qualify for Boston, my measure of a good running pace.  I gave it a go in Kona this past October (2019).  

Unfortunately, the results, in Kona, for reasons I believe other than the run/walk, did not live up to my expectations.  My run was a long way off my potential due to back problems.  However, there is no doubt in my mind that had I not followed the planned run-walk strategy, it would have been the slowest IM of my career and there was a good chance I might not have finished.  Just that 15 sec. walking plan gave me time to stretch my back and keep the momentum going.  It also helped greatly knowing that I had to put up with the discomfort of my back for only 30 sec. at a time (the decision to go to 30 sec. was made just before the race because of my back.).  

Since I started doing more than just walking every mile (aide stations) I have not been totally compulsive about it.  If I am heading down a gentle hill I might skip a walk. If there is an aide station 20-30 sec. ahead I would run into it.  When I get to mile 23 and the adrenaline kicks back in, I run to the finish, especially if there is competition nearby.  Conversely, if I see competition at a turnaround, as I did this year in Kona, I would not change my plan, just try harder to run fast when I run.   

So, at any opportunity these days I encourage my athletes and friends who ask to experiment with the run-walk approach.  You do need to practice it and this time of year (off-season) is the perfect time to try something new.  How long you should run and walk depends a lot on your running speed and goals.  Younger, faster runners would probably find that 30/15 is way too short.  However, everyone is unique when it comes to athletic ability, and most other things, so experimenting is essential.  My approach of starting with longer run intervals is probably a good way to go but don’t take several years to reach a good choice, one winter is more than enough time.

Click here for my Walk-Run Pacing Calculator

If you have questions, please reach out to me at

This article by Jeff Galloway will help you find a good starting point. Just remember that Jeff, for the most part, is talking about marathon and half marathon running, not some crazy sport that has you swimming and biking for at least 2-3 hrs. first.  

Coach Simon Butterworth is a USAT Certified Coach and in the big picture sees attitude more than age making the difference in many aspects of this sport. There are times in triathlon that to see improvements you need to slow down and spend some time working on your technique – which requires a great deal of discipline. So does having a coach and following the plan written for you. The best coach in the world can only be of help if you’re ready and willing to do the work.

Coach Simon Butterworth has an experienced philosophy about coaching.  The key ingredients in a good coach/athlete relationship are regular and open communication, mutual respect, and keeping it fun for the athlete and their family.  His training programs are developed with those ideas at the forefront. He works with athletes to develop both short-term and long-term objectives that work well within the context of the other things they have going on in their life.

Coach Simon is a 2X World Ironman Champion and has 16 Ironman World Championships races to his credit. He has finihsed on the podium 7x.  He is a USAT Certified Coach, USMS Swim Coach, FIST Certified Bike Fitter and Training Peaks Certified Coach.

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