What Place for the Marathon in Ironman Training?

For an Ironman athlete there is only one place for the marathon: after a 3.8km swim and a 180km bike. I’m often asked if a marathon is a good idea during Ironman training. My answer is always no. Before I focussed on triathlon I competed in them; once my goals were in multisports I put them aside. I couldn’t achieve all I wanted in running if I was dividing time and energy with other sports. Similarly I couldn’t reach my best as a triathlete if I was committing to a marathon as well.

I often stress the value of specific race practice. Using training to test and learn how you’ll execute your race is an important part of god preparation. A marathon is not specific race practice. The distance is the same, but conditions are different. Most obviously you won’t be following a long swim and bike; Ironman running is performed in a state of fatigue and glycogen depletion. You’re not practicing this particular stress. The pace will be slower than a standalone marathon; you’re not even practicing Ironman pacing.

The run is the most destructive stage of an Ironman, but it’s nothing compared to a marathon. Fatigue remains high, but the slower pace reduces the muscle damage. A marathon may be shorter, but the recovery is comparable; a matter of weeks before you’re training well. Race a marathon midway through the build to your key race and you potentially set back a month of training. You’ll train, but not as well. The more consistent, race free pathway will have you fitter and better prepared to perform in the Ironman.

What if you run the marathon at Ironman pace? Can you do that? Do you want to? I struggle to hold back in training let alone racing. I race with the intention of performing my best. I can practice for a race in training; I put everything in for racing. An Ironman paced marathon is a tough session and is more race specific, but it’s still not good training. The marathon is too long: it will require recovery and it will impact subsequent training. Running a shorter distance, recovering and training well the next day is preferable.

Confidence is often a reason for novice Ironman athletes to try a marathon. You want to know how it feels before you face it at the end of a swim and bike. Do you really? It might put you off the whole idea! How you feel in a marathon is different to how you feel in an Ironman. I won’t deny it can help confidence. Quality training, effective practice: these build confidence without the expense of extensive recovery. Ironman marathon performance is about good fitness, good pacing and good nutrition. It’s not about your ability to cover 26 miles alone.

There are many reasons to race. It might not be optimal, but you may still want to race a marathon. If you really must then you need to consider your overall priorities and goals. The further your marathon from the Ironman the lower the chance of it affecting the race. It might not impact your performance, but do you want that risk? You may need to compromise on your goals. If your priority is the Ironman place the marathon well away from it. You’ll probably emphasise running before the marathon and once recovered you’ll need time to focus on swimming and cycling.

If racing is the motivation, there are plenty of shorter events. A well executed half marathon is of far more value than a slow marathon. You test your ability to sustain a hard effort, harder than Ironman pace, but not for sufficiently long to do as much damage. It’s an excellent training day: you can actually race and the impact on your schedule should be minimal. Racing is important. Going all out practices pushing your limits and working hard under stress. Those are relevant to the Ironman. ‘Racing‘ at Ironman pace doesn’t tell you anything you can’t learn in training.

Good preparation for an Ironman marathon is built around developing durability and endurance; the relevance of speed is limited. I do small amounts of work at high pace; my emphasis is on combining high frequency with a dose of long distance and a heavy portion of hills. There needs to be a balance of intensities, but generally the pacing of a good Ironman is comparable with a long steady run. Progress should be towards being able to run distance comfortably and recover well, before there is too much concern about how fast you can run.

Combing a marathon and Ironman is possible. You’ll make it through both. The real question is whether you’ll perform as well as you wanted? Think hard. Would you be happy with a marathon PB missing your Ironman goals in the process? Could you run an ‘easy‘ marathon with the intention of performing better in your Ironman? Save the marathon for the end of the season or dedicate time specifically to it. Don’t consider it part of your Ironman preparation.

Ironman Training Library

From nutrition to pacing - a collection of CoachCox blog posts focused specifically on Ironman training and racing.