Essential advice about the optimal running pace, heart rate and perceived exertion to run a fast Ironman marathon.
Did you realise that by the time you start the marathon run in an Ironman triathlon, you’ll have already been racing from anywhere between 5 hours 30 and 12-hours?
You’ll be tired and low on energy by then, so your pacing strategy needs to reflect that. The best outcome you can realistically expect in an Ironman marathon is to maintain an easy or steady pace throughout, without having to stop or continually walk. That is the secret to achieving an excellent Ironman result and in this blog we'll show you how...
What is The Perfect Ironman Run Race Pace?
There is precious little research on the ideal pace for an Ironman but there is one particular study that sets the tone of this blog. It appeared in the journal PLoS One and was based on athletes who competed in one of the world’s most challenging ultra-marathons, the Tor des Geants in Italy. This gruelling event involves running 200 miles over mountains, with 24,000 metres of elevation change. The researchers compared these hard core athletes with another group who’d taken part in a shorter Alpine ultra-marathon – a mere 103 miles in length.
The findings showed that runners in the longer race had lower levels of muscle damage and inflammation, despite the fact that they ran almost twice the distance as those in the shorter event. The researchers were led to conclude this: “Such extreme exercise seems to induce a relative muscle preservation process, due likely to a protective anticipatory pacing strategy during the first half.”
How does this help you?
Well it implies that the athletes in the longer event paced it more carefully from the start, compared to those doing the shorter event. And that even with distances of 100 miles and 200 miles, small differences in exercise intensity can make a big difference to your muscle fatigue levels.
So bearing that in mind, here's how to set yourself a realistic pacing plan, using three different measures...
1. Ironman Run Heart Rate
You should start your Ironman run at 65 to 70% of your maximal heart rate. For example, if your max heart rate is 170 beats per minute, start running at 110-120 beats. Sounds low right? Keep this up until halfway and then you can increase your pace slightly if you feel fresh enough (but the chances are you won’t).
2. Ironman Run Perceived Exertion
Based on your perceived exertion your Ironman race pace should feel like a 2 or 2.5 out of 10 on the intensity scale, with 10 being your all-out maximal effort. On a good day this might be described as being an “Easy" pace.
3. Ironman Run Pace
If you know you recent best time for a 3km, 5km or 10km race or time trial, you can use this Matt Fitzgerald Running Zones Chart to estimate your Ironman run pace. Look up your recent race time using the left hand columns of the table. Then trace your finger right until you get to the column that says "2: L Aero". This column gives you a range of paces that you should stick to during your Ironman run. This pace would feel super easy on a normal day, but is an ideal intensity for Ironman.
Just make sure you base your pace on real results from a 3km, 5km or 10km - done in the last 8 weeks. DO NOT GUESS!!!
Final Ironman Run Tips
By Phil Mosley.
Triathlon Plus Coaching Editor & Ironman Certified Coach.
Founder of My Pro Coach.
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Copyright © 2016 Philip Mosley
The Serious Training Blog
Train Smart. Race Fast.
Phil Mosley is a triathlon coach and writer.