Marathon Runner to Ironman – how to master the Swim and Bike


Running a marathon is a huge and incredible achievement. I imagine at the end of your marathon(s) you feel completely spent. But you have heard Ironman Triathletes complete a Marathon after swimming and cycling for miles before hand. You may struggle to figure out how that’s possible! I can promise you if you have the mind-set to train and run an Marathon you will be able to make the step up from Marathon runner to Ironman Triathlete easily enough. I will also address shorter distance runners and what it takes for them to step up.

First let me let you in on a little secret, promise to keep this to yourself as us Ironmen really don’t want everyone to know. but:

An Ironman Marathon is considerably easier than a Stand Alone Marathon!

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Quite a statement! how can I possibly justify it? a marathon is a marathon right. 26.2 miles of running. How can swimming 2.4mile and cycling 112 miles first make it EASIER. Well the simple reason is speed.

Most people fail to pace a standalone marathon correctly. They start out too fast and by the end they fall apart. This break down is why most people find marathon running so difficult. Even a correctly paced marathon Still makes you suffer an awful lot near the end as you are right at the limit of the human bodies ability.runner in pain

The Hardest part of marathon running is the physical degradation in your muscles and joints. You are literally smashing your self to pieces. Swimming and cycling don’t effect the body in that way. So in that context you are still fresh when you start the Marathon. However in many other ways you are highly fatigued.

The Fatigue developed from the swim and bike MAKE you run slow.

From the off you are just running a fair bit slower than you would during a stand alone marathon. So by hr half way point you muscles and joints have not accumulated anywhere near the same level of stress they would have in a standalone. So by the time you reach the latter stages the parts that are really hurting and failing during a marathon are still “reasonably” fresh.

I normally find quite a second (well more like 19th by this point) wind during the last two – three miles of the ironman marathon. I find myself picking up the pace considerably where in a standalone I’m falling to pieces and just trying to hold on to any kind of pace towards the line.

Of course that means you won’t be likely to set any PB’s, assume 30mins – 1hr slower, but it often means you can really enjoy the event and soak up the support and atmosphere!

Great so I’ve got the Marathon in the bag! But how do I get there? I can’t Swim / Ride a bike!

There is both good and bad news here, firstly there is no doubt in my mind that if you can run a marathon you have what it take to develop the other two disciplines and probably within a pretty fast timescale. Its just a case of cracking on and learning the Techniques and skills needed in the disciplines and conditioning your body to be able to manage long, sustained periods of the activities. 1-2hrs of swimming 5-8hrs on the bike.

If you are a complete novice at swimming and biking check out the Couch – Ironman guide as it will provide advice for complete novices to the sport. Obviously just understand you have a good level of base fitness and a terrific engine so you are only adapting that to new activities. Progress should be quick considering where you are at. But learning new techniques can be frustrating and time consuming. Especially swimming as a runners build is not perfect for swimming, as they tend to have heavy sinking legs.

I’m an experienced runner but never done a marathon? Could I still do an Ironman.

Yes, absolutely. My first Marathon was part of the Outlaw Iron-distance triathlon Nottingham. The furthest I had covered before that was 21 miles. But prior to beginning Ironman training I had never covered more than a 10k (6.2miles)

The fact you are already running and active is a great start. Now its just a case of pushing out your distance and working on fuelling and nutrition strategies. Along with the (not so) insignificant task of Swim and Cycle training.

Think Back.

Remember when you started running. Whatever your chosen distance. It probably seemed impossible. You are not a runner, how can you possibly do this. That’s just where you are again. And like your previous goals you can do it. All you need is the metal toughness to carry out the required training and some time learning new skills and techniques.

Let me know if you decide you are going to complete an Ironman? Where are you starting from? Feel free to leave a comment below about your journey or anything else related to this post






  1. I love that you included the information for those of us that have been running for a long time, but never actually entered a marathon. I used to run cross country in high school, but it’s been a while. I am really excited to get back into competition and I think you have listed some information that will be very helpful for me. Even though I already run. I think the Couch to Ironman guide will be helpful for me as well! Thanks!

    • Hi thanks for reading,

      I do hope some of that info will be of help. Yes even though you have done plenty of running in the past if you are not fit at the minute the couch to ironman plan would probably be useful as well. Its not just intended for complete non athletes but anyone who is currently not exercising.

      I hope you enjoy your return to competition. Triathlon and Ironman is such a fun, inclusive and exciting sport. I’m sure your running background will leave you in good stead, Its a lot more than I had when I started.

  2. Never thought that an Ironman would be “easier” than a marathon Being forced to run slow in this case I guess is helpful. It’s like the race paces you instead of you controlling the pace. I personally run Spartan Races and it is easy to gas out at the beginning so I can understand the trick with marathons.

    • hI, thanks for reading and for the comment.

      To be clear, it’s only the ironman marathon that’s easier, the bike and the run obviously make the event overall much more of a challenge, you just don’t suffer the same during the ironman marathon as you do in a stand alone. The tail end of the bike, can be particularly tough at times. Especially if you have over paced it. which can also lead to a long painful marathon.

      Like all events including spartan races, the trick is always to pace correctly. Just with ironman going out to eagerly really can leave you in a bad place with a long way to go.

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