A Spring marathon before a summer Ironman?

Recently, I was asked my opinion on whether one of my triathletes should do a marathon in the run up to an Ironman. It’s a question that always provokes hot debate on internet forums, and he was confused by the conflicting advice that he was getting.

If you’re in a similar position, I’ll run through some of the considerations that I went through with him.

Do you have to do a marathon in your Ironman preparation?

I don’t believe that you have to complete a marathon as part of your Ironman build. In fact, for the majority of triathletes (and especially if it’s your first Ironman,) I’d advise against it. The first timers that I coach won’t complete a marathon until they cross the finish line of their first Ironman.

Most triathletes would be best advised to use the spring to build their endurance in the way that will most benefit their Ironman preparation – on the bike.

If you can run often and stay injury free, it’s a good idea to put in some extra run miles during the winter when it’s dark and it’s hard to get out on the bike. I think it makes much more sense to then run a half marathon if you want to test your run fitness. You’ll recover faster and there’s far less danger of injury and burnout.

Will racing a spring marathon be detrimental to your performance in a summer ironman?

If you prepare properly to race a marathon (and by that, I mean a block of 16 weeks or more of run focus, with five or six runs a week,) then in all likelihood you’ll be building a great fitness foundation for your Ironman training block. This is especially true if you have the time to do this whilst maintaining your swimming and biking.

On the other hand, it’s important to be realistic about the time it’ll take you to recover, both physically and mentally. In 2009, when I prepared ‘properly’ for London, I was physically recovered in a week, but mentally it took a lot longer to ‘want’ to get back into training. I had to dig very deep on race day – possibly deeper than I ever have, before or since – and for a good few weeks afterwards all I wanted to do was play my guitar. It was probably the biggest break I’ve had from training that wasn’t injury related in five years!

I’m not sure that I’d recommend to anyone that I coach that they follow the program that I’m setting myself, but I really want to give it a try. I want to use my fitness for as many great athletic experiences as I can, and they don’t come much great than the London Marathon.


Things to consider before you undertake a big block of winter run training

Cross train

Don’t be a slave to run miles. Cycling is a very effective replacement for an easy run; just as effective at training your aerobic threshold and fat oxidation, but without the blunt trauma on your joints. However, just make sure you know the purpose of that bike session. 30-60 minutes at aerobic threshold will leave you refreshed for the next days run. 30-60 minutes at functional threshold won’t!

Walk breaks

Gordo switched me on to the benefits of walk breaks, and all of my long runs (anything over an hour) are done with a 1 minute walk every 9 minutes. The benefits to your recovery are amazing. Yesterday I did a 2 hour run, and today I didn’t feel even slightly sore. The mechanism isn’t well understood – it’s thought that possibly a change of gait between walking and running helps muscles to recover during the run, rather than them becoming ‘engorged’ with blood. Whatever the reason, it has a material effect on my recovery and I’m sticking with it for myself and my athletes.

Vary the surface you run on

With all the snow and ice we’ve had recently, I’ve rediscovered the joys of the local canal towpaths and parks. Hardly any of my running has been on roads, and I’ve even gritted my teeth and hit the treadmill a few times. I’m enjoying the freedom from taking mile splits all the time, and I know that plenty of steady running will build a foundation for the faster threshold work to come.

Injuries and biomechanics

If you’re injury free, and biomechanically sound, that’s one less thing to worry about. However, if you have any kind of recurring running-related injuries, then ramping up the running volume is a good way to be reminded of them. If you suddenly start running six times a week, it could well be a recipe for disaster. Get your gait checked out at a reputable running store that does video analysis of your stride on a treadmill, and buy shoes that address any biomechanical issues that you might have. In my personal experience, the wrong shoes can make a massive difference to injuries!

Body Composition

One area most of us can improve on is our body composition. Losing a few pounds will have a double effect – firstly, a lighter body will produce less impact on our joints. Secondly, just by being lighter, you’re effectively increasing your VO2max (the amount of oxygen your body can take in per kilo of body weight – so less body weight means a higher VO2max.) Just by carrying less body fat, you’ll run faster for the same effort and fitness.


For triathletes like me who ‘were’ runners in a former life, the lure of a big city marathon (especially London) will always be there each year. Cracking 2.45 and securing a Championship time is my first big goal of next year. As long as I stay injury free, I believe I can do it. (Interestingly, not many of my running buddies believe that I can!) More importantly, I believe that a big winter run block will set me up for a really good crack at a fast Ironman later in the summer.