Ironman pacing with powermeter and FTP
Jakob Ohlsen Published: 9th January 2018
Pacing yourself is key to success in any endurance event. If enthusiasm and the adrenalin rush drive you too quickly at the start, you may not make it to the finish line. Strategy and mindset can be as important as all the hours of physical training.
When it comes to Ironman events, it's important that you approach them as an endurance trial and not a race. As you become more experienced, you'll want to improve your time, but finishing should always be your priority. Top athletes on the Ironman circuit understand the importance of pacing themselves and have the discipline and mental strength to stick to their strategy.
Pacing on the bike
In Ironman triathlon events it's the bike section where pacing is critical. If you burn out your legs by riding too hard, your chances of completing the run are significantly reduced. If you do make it through, every step will hurt, and your chances of injury are increased. Holding yourself back at a manageable pace can be a real challenge when other riders are passing you by, but you'll thank yourself as you settle into the run stage. At around the eighty-mile stage, you see some of the competitors who overtook you earlier starting to drop off, and a good pacing strategy will allow you to catch up with others.
Getting the bike stage right sets you up physically and mentally for the challenges ahead. Attempting to ride at a constant power output beyond your physical ability can give you stomach problems as well as leading to exhaustion. Riding in bursts or tackling hills with inappropriate gearing will also leave your body in poor shape for the 26.2-mile run.
A disciplined pacing strategy leads to more consistent Ironman results and ultimately helps you to improve your finish times. It's something beginners to endurance events often ignore, and this can lead to athletes quitting during the later weeks of training. Another benefit of correct pacing is that it helps you digest snacks and energy drinks during a triathlon, and these are important for fuelling the body as you enter the run stage.
Pace yourself by using your FTP
Fortunately, there is an easy way to pace yourself for a triathlon. The scientific measure for cycling performance is Functional Threshold Power, commonly known as FTP. In simple terms, FTP is the optimum power output you can maintain for an hour. It's a useful measure for all kinds of endurance events, and knowing your FTP enables you to analyze your performance, track how your fitness levels and set pacing strategies for triathlons and other events.
| Expected finishing time | Percentage of FTP |
|---|---|
| 8 to 9 hours | 78-80% |
| 9 to 10 hours | 76-78% |
| 10 to 11 hours | 74-76% |
| 11 to 12 hours | 72-74% |
| 12 to 13 hours | 70-72% |
| 13 to 14 hours | 68-70% |
| 14 to 15 hours | 66-68% |
| 15 to 16 hours | 64-66% |
Once you know how to determine your FTP, you can adapt your training and increase your chances of success in any endurance event. A powermeter is all you need for this. The baseline test is commonly known as a 'CP20,' and it involves riding as hard as you can for twenty minutes and measuring your average power. Multiplying the average power figure from your CP20 by 95% gives you your FTP. You may not have thought of buying one before, but this is why a powermeter is so important for triathlon training and racing. There are many powermeters on the market. Personally I use a power2max Type S, which served me very good so far.
Studies indicate that the poweroutput for the bike stage of an Ironman event should be at around 65%-80% of your FTP (depending on your expected finishing time - see table above). Your finish time in a triathlon will, of course, improve if you are able to maintain a higher FTP, but this is a goal to achieve over time.
