How to master the Ironman run

Six tips to help ensure you train, fuel and pace properly and finish the 42.2km run strong


Making the step up to Ironman this season? Unless you come from a strong running background, the chances are your biggest concern is going to be the 42.2km at the end of the day.

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The infamous 1997 ‘Crawl-Off’ between Sian Welch and Wendy Ingraham at Ironman Hawaii shows even athletes at the sharp-end of the race can literally be brought to their knees.

But with smart and consistent training, solid nutrition and a realistic approach to pacing on race day, the marathon need not be an exercise in suffering and survival.

For a long-course triathlete, cycling is arguably the key discipline. It represents the biggest chunk of the race and has a huge impact on the run. Never neglect your cycling training and make sure you’re getting in those long rides.

If you’re strong on the bike and can avoid the temptation to overcook it on race day, you’ll hit the run in better shape than a weaker cyclist. Time on the bike will also make you a stronger runner, and if you want to include some higher intensity work, doing it on the bike is far less likely to result in injury than faster paced runs.

Do enough swim training so you can cover the 3.8km swim in a reasonable time without it taking too much out of you. But, for time invested in training versus time gained on race day, the swim yields the poorest return by far.

You’ll read about long-course pros doing significant amounts of running speedwork, but for the majority of age-groupers it’s counterproductive and will lead to injury and unnecessary fatigue.

Tempo (heart rate Zone 3) is as fast as you need go. The key run session is the long, steady distance with a chunk at race pace. You’ll be running with fatigue in your legs on race day at Ironman UK, the Outlaw or Challenge Weymouth so you might as well get used to it in training.

Zones explained

Here we’re working with Joe Friel’s HR zones for the run, measured by your lactate threshold heart rate (LTHR).

To calculate your own, warm up properly before cycling at your hardest pace for 20mins while using a heart rate monitor. Your average heart rate for this period is your lactate threshold heart rate.

Zone 1 – less than 85% of LTHR
Zone 2 – 85% to 89% of LTHR
Zone 3 – 90% to 94% of LTHR
Zone 4 – 95% to 99% of LTHR
Zone 5 – 100% to 106% of LTHR

Mental conditioning

You’ll be building significant stamina on the bike, so you don’t have to do the mega long runs that are the mainstay of pure running programmes.

If you haven’t already got a marathon under your belt, doing one during the spring before a summer Ironman is a good mental box to tick.

This distance should be a one-off that you taper well for, though. Factor in enough recovery time and don’t revisit that distance until your long-course tri debut.

Run session variation

With your long run in the bank, doing two other run sessions during the week strikes a good balance between training enough and avoiding injury.

One should be a tempo run consisting of 10mins warm-up, building through Zones 1 and 2, a solid 20-40mins at tempo (Zone 3) and 10mins jogging to cool down.

The other should be a 60-90min steady run, the majority of which should be Zone 2, which can be done faster.

Bike/run bricks

I’ve always been a big fan of the brick and recommend tagging a 10-15min Zone 3 micro-run onto every bike session. It gets you used to the horrible ‘jelly legs’ sensation but, more importantly, reassures you that it passes.

Three weeks out from race day, aim to complete a ‘Metric Ironman’: 2.4km swim, 112km bike and 26.2km run. From then, as you begin to peak and taper down, bricks should be training staples but with a decreasing amount of running.

Pacing is key

For long runs, include a significant chunk (about 80%) at your marathon race pace. If you haven’t run a standalone marathon, there are online calculators that allow you to extrapolate training paces from your shorter-distance times (I recommend Daniel’s Running Formula).

Longer brick sessions such as your ‘Metric Ironman’ should be run at your M-Dot race pace. A good rule of thumb is to take your standalone marathon race pace and add 20%.

If you’re using heart rate, aim for low to mid-Zone 2, but it’s best to refer to pace as well because muscular fatigue and cardiac drift flatten heart rate relative to effort on long runs and bricks.

Experiment with nutrition

Mirinda Carfrae has said that training to increase her calorie intake on the bike has allowed her to race, rather than survive, the run. Work on your bike leg nutrition; no matter how good race day goes, you’re unlikely to be able to stomach solids on the run and will rely on those bike-banked calories.

On your long runs, experiment with different gels and energy drink mixes to find the ones you tolerate best. Aim to consume a gel or its equivalent every 20-30mins and try downing flat cola during the last hour of sessions – it can often be a stomach-settling race-day lifesaver.

Stretch to sidestep injury

With at least three bike workouts and a couple of swims a week to fit around your running, you’re far less likely to pick up injuries than a pure runner. Nonetheless, keep on stretching, especially if you work at a desk.

Including simple exercises such as single leg squats and lunges in your warm-up can also help undo the damage of sitting.

Also, vary your running surfaces. Get out onto the trails and hills every 3-5 weeks for your long run – forget pacing, run on feel and just enjoy it. Your mind and body will thank you for it.

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(Images: Ben Winston)