How to run a marathon while on an IM plan

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    How to properly run a marathon while doing an IM plan? I read the 80/20 Tri book. There are examples of how to plan multiple triathlon races over the season, but it is still unclear to me how to mix triathlon and running. I have both IM and marathon plans in my TP library. Does it make sense to combine them in any way so that some period of IM plan would be shifted to more marathon specific run workouts? IM is the primary goal so I do not want to degrade bike too much, but of course I want to run marathon as best as I can. Or that mixing is too complicated? If so I thought to just slowdown for couple of weeks before the marathon, run it as I can without specific preparation, then recover for a week and get back to the normal IM plan flow. Also, what period of the IM plan is easier to inject the marathon race into? I understand that an answer would require considering more variables so answering in general terms would be good enough for me.


    David Warden


    Yes, this is complicated. It’s important to understand that while marathon and Ironman are similar, they are two very different sports. There is a reason there are no professional cross-over athletes. You can be good at both, you can only be great at one at a time.

    Training for an IM and a Marathon at the same time is like trying to make something both a pizza and a cake at the same time. You can bake one or the other.

    The best decision is to split them up by at least 12 weeks and train for them separately. If you must include a marathon as part of Ironman training:

    – Replace your shortest cycling workout with a run and follow the workout as a run
    – Add a run of 60-90 minutes each week, all Zone 1-2
    – Increase your longest run each week by 30 minutes, but no longer than 3 hours

    We do offer a custom plan service that can help with this, see



    David, thank you. That is interesting. I will try to workaround based on that.

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