Learn how to structure your race pace strategy to optimise your potential in your IRONMAN 140.6.
Sensible pacing will make a massive difference to your IRONMAN race-day performance. The most successful IRONMAN athletes know exactly how to pace themselves and have the mental strength to execute their pacing strategy on race day. Sometimes that will mean you need to switch off your competitive race-brain and trust in your pacing plan. Go too hard in an IRONMAN and you'll be paying for your mistakes all day long.
IRONMAN Swim
An IRONMAN swim is a huge challenge. It involves swimming 3.8 km in open water, among hundreds or thousands of athletes and with no opportunity to rest. It's a scary prospect, especially if you're not the most confident swimmer. In addition, you also need to save your energy for a 180 km bike and a marathon run afterwards.
Therefore, your IRONMAN swim should be done at a nice steady pace*. There are several ways to pace yourself, including heart rate, pace and RPE. From a practical point of view, using RPE (feel) works well - it saves you trying to look at your watch.
Rate of Perceived Exertion For IRONMAN Swim
- Feels steady
- A High Z2 intensity that feels like 4 out of 10 (where 10 is your hardest)
Heart Rate
- Percentage of your Maximal Heart Rate: 60 to 70%
- Beats Below Maximum Heart Rate: 30 to 50 beats
Pace
- Take your fastest 100 meter or yard training pace and add 10 secs per 100 meters or yards
- If you’re racing in a wet-suit, make sure you base your pacing strategy on your recent wet-suit training times (and vice versa)
*The strategies above apply to the majority of athletes. However, if you’re aiming for a sub 10-hour IRONMAN (men) or sub 11-hour (women) it’s a good idea to go a little harder in the first 300 to 400 metres of the swim. Let’s say 8 out of 10 intensity. This can help you get clear of the crowds and find similar or slightly faster swimmers to draft behind. Providing they’re going straight, you’ll save up to 10% of your energy for the 3.8km by swimming directly behind or by their hips. After the first few hundred metres you should settle down to 5 out of 10 and preserve your energy for the long day ahead.
IRONMAN Bike
The bike section is where pace judgement is most vital. Riding too hard will make it much harder to run afterwards. There are three big mistakes that people make:
- Attempting to ride at a constant intensity that is slightly too high.
- Riding in bursts, ranging from easy to hard - without realising.
- Riding too hard on the hills without realising, often due to inappropriate gearing.
It is important to not base your pace-strategy on the bike split that you would 'ideally like to do'. Use the pacing guidelines below and be realistic with your goals.
Power Output
|
IRONMAN Target |
% FTP |
| 8 to 9 hours | 78 to 80% |
| 9 to 10 hours | 76 to 78% |
| 10 to 11 hours | 74 to 76% |
| 11 to 12 hours | 72 to 74% |
| 12 to 13 hours | 70 to 72% |
| 13 to 14 hours | 68 to 70% |
| 14 to 15 hours | 66 to 68% |
| 15 to 16 hours | 64 to 66% |
Threshold Heart Rate (THR)
|
IRONMAN Target |
% Bike THR |
| 8 to 9 hours | 88 to 90% |
| 9 to 10 hours | 86 to 88% |
| 10 to 11 hours | 84 to 85% |
| 11 to 12 hours | 81 to 83% |
| 12 to 13 hours | 78 to 80% |
| 13 to 14 hours | 76 to 77% |
| 14 to 15 hours | 73 to 76% |
| 15 to 16 hours | 69 to 72% |
Rate of Perceived Exertion (where 10 is the hardest)
|
IRONMAN Target |
RPE (feel) | Zone |
| 8 to 11 hours | 5 to 6 out of 10 | Low to Mid Z3 |
| 11 to 14 hours | 3.5 to 4 out of 10 | High Z2 |
| 14 to 16 hours | 3 to 3.5 out of 10 | Low to Mid Z2 |
Riding at the right intensity takes discipline and courage, especially when other people are overtaking you. But it really works. At around the 80-mile point you'll notice people starting to drop off, while you continue to ride strong. You'll also find it easier to digest your race-nutrition, helping you maintain your energy levels going into the run. You will run faster as a result of pacing yourself properly on the bike, and you'll feel fresher and more energised.
IRONMAN Run
By the time you start the marathon run in your IRONMAN, you’ll have already been racing from anywhere between 5:30 and 12 hrs. You’ll be tired and low on energy, 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.
Threshold Heart Rate (THR)
|
IRONMAN Target |
% Run THR |
| 8 to 11 hours | 85 to 87% |
| 11 to 14 hours | 82 to 86% |
| 14 to 16 hours | 78 to 82% |
Rate of Perceived Exertion (where 10 is the hardest)
|
IRONMAN Target |
RPE (feel) | Zone |
| 8 to 11 hours | 3/4 out of 10 | Low to Mid Z2 |
| 11 to 14 hours | 2/3 out of 10 | High Z1 to Low Z2 |
| 14 to 16 hours | 1/2 out of 10 | Mid Z1 |
Pace
|
IRONMAN Target |
% Threshold Run Pace |
| 8 to 11 hours | 82 to 85% |
| 11 to 14 hours | 78 to 82% |
| 14 to 16 hours | 74 to 78% |
Keep your intensity conservatively low - at the bottom end of the scale until halfway. At that point, if you feel fresh enough, you can increase your pace slightly (however the chances are you won’t).
Using all three of the methods (feel, HR and pace) is best as none of them are completely reliable in isolation. There are many variables that can affect them such as wind direction, gradient and cardiac drift (an increase in heart rate due to heat stress). Just remember that the downsides of starting too fast are far greater than the downsides of starting too slow.
For All Disciplines
Ensure you base your IRONMAN pacing strategy on real results from fitness tests done in the last 8 weeks. DO NOT GUESS!!!
Fitness Tests To Determine Your Thresholds
Your IRONMAN success will be determined by how hard you went in the bike and swim sections - and your nutritional strategy. If you cycle too fast you will struggle to run the marathon properly. If you pace the bike section intelligently and get your nutrition right, the chances are you’ll run well. Check our article for more on Race Nutrition.
The longer you anticipate you'll take to complete an IRONMAN, the lower your intensity should be. For example, if you think you'll take 15 or 16 hours in total, you should aim for the lowest possible end of the pace, heart rate and exertion suggestions above.
To read more about IRONMAN pacing, check out our blogs:
RUN: https://www.myprocoach.net/blog/how-to-pace-an-ironman-run/
BIKE: https://www.myprocoach.net/blog/ironman-bike-pace-guide/
SWIM: https://www.myprocoach.net/blog/five-ironman-swim-tips/
Good Luck for your IRONMAN!
Copyright MyProCoach™ Ltd © May 2018. All rights reserved.
Comments
1 comment
I read an article about pacing an Ironman about 7 years ago. It said to swim a comfortable pace then on the first hour of the bike go slow, let people pass you then find your pace and the last 6 miles you will be finishing strong. It's worked well for me finishing on the podium and winning my AG last year at IMMD. Kona bound.
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