If you’re aiming to do a half-distance triathlon, such as an Ironman 70.3 event, your pacing strategy can make or break your race. In this article, I reveal how to get it spot on.
How far is a half-distance triathlon or IRONMAN 70.3?
A half-distance triathlon, such as an IRONMAN 70.3 event, is the first step into the world of long-distance triathlon.
This event consists of a 1.2-mile swim, a 56-mile bike ride, and a 13.1-mile half-marathon run (1.9km, 90km, 21.1km). It might take you anywhere between four and eight hours to complete this distance.
So, let’s say, for argument’s sake, a half-distance triathlon takes five or six hours. Well, that’s a long time to be swimming, cycling, and running, and you’ll need a pacing strategy that reflects that duration.
If you get your pacing wrong and set off too fast, you’ll be hit with fatigue and sore legs in the second half of the race. And not only will that lead to slower times, but it’ll also make the whole experience feel unpleasant.
Sensible pacing also makes it easier to process your energy gels, chews and drinks, providing you with more energy and fewer GI issues.
In this article, I’ll explain how to pace yourself accurately so that you feel strong throughout the entire race. I’ll talk you through the swim, bike and run sections, and give my recommended pace targets at the end of each section. Plus, Right, let’s start with the swim…
Half Distance Triathlon Swim Pacing
Pacing yourself during the swim is the most difficult part because you can’t look at your watch to see how fast you’re going. Add to that, the first few minutes of a triathlon swim are a frenzy of closely packed swimmers all trying to make a fast start. If you’re anything like me, you’ll experience a surge of adrenaline, which makes it hard to maintain a sensible pace.
For those first few minutes, aim to swim at an intensity that feels like a 7/10, or perhaps 8/10 if you’re a sub-5-hour athlete. And remember to breathe out fully between each stroke so that you don’t get into a breathing panic.
After the first few minutes, the pace usually eases, and people find themselves more spread out. At that point, you can ease back slightly so that you’re swimming at an intensity that feels like 6 out of 10, or perhaps 7 out of 10 if you’re a fast age grouper.
Pacing in Transitions
Once you’ve finished the swim, it’s time to head into Transition 1, to grab your bike. It’s important not to raise your pace here, as you’ve still got a long day ahead of you. You often see people sprinting like Usain Bolt at this point, but just ignore them. This is a long event, and you should not feel out of breath at any point. Simply jog or walk the transitions and save your legs for later.
Half Distance Triathlon Bike Pacing
How you pace yourself on the bike, will make or break your race. Not only will it affect your bike split, but it’ll also determine how well you cope with the run section. You cannot afford to get this bit wrong.
I’ll give you some specific pacing advice in a minute, but first, you’ll need to work out how you’re going to gauge your intensity on race day. Consider metrics like speed, heart rate, power, and Rate of Perceived Exertion, known as RPE.
Speed is the worst way to gauge your pace because it relies on too many outside variables, such as weather and gradient. Whereas power output in Watts is the best method because it comes straight from the source and instantly reflects any changes in your effort.
If you don’t have a power meter, you can use heart rate or RPE instead. Heart rate is useful, although it’s slow at responding to changes in intensity. Whereas, RPE is simply a number between 1 and 10 that reflects how hard your effort feels, with 10 being the hardest you can pedal and one being the easiest.
Whichever method you choose, you should aim for a consistent, smooth application of effort with no spikes. That can be tricky on hilly courses, particularly if you run out of easy gears. In that case, you might benefit from fitting a compact chainring and a rear cassette with a 30 or 32-tooth cassette. This should give you enough gears to maintain a nice steady power output at your normal cadence on all but the hilliest routes.
Lastly, before I give you some bike pacing numbers, it is important not to base your pace strategy on the bike split that you would “ideally like to do”. Rather, base your pacing goals on what you’ve demonstrated consistently in recent training, on your race day bike.
Here are my pacing guidelines for the bike section. You can use either power output, heart rate or Rate of Perceived Exertion. If that all looks too complex, we also have a triathlon race pace calculator on this website, which you’re welcome to use.
Half-Distance Triathlon Bike Pace Guide
Here are the three ways I recommend you pace a half-distance bike split, such as an IRONMAN 70.3 or middle-distance triathlon.
1. Using a power meter
A power meter is a device that measures your power output in watts. With this you can work out your mean average power output for a one-hour cycle time trial at your best effort which is known as your Functional Threshold Power (FTP):
Race target time: Sub 5 hours > Aim for 83 to 84% of your FTP.
Race target time: 5 to 6 hours > Aim for 80 to 83% of your FTP.
Race target time: 6 to 8 hours > Aim for 77 to 80% of your FTP.
2. Using a heart rate monitor
A heart rate monitor is a cheap and effective tool to identify your Threshold Heart Rate (THR) which is your mean average heart rate for a one-hour cycle time trial at your best effort.
Race target time: Sub 5 hours > Aim for 88 to 92% of your THR.
Race target time: 5 to 6 hours > Aim for 84 to 88% of your THR.
Race target time: 6 to 8 hours > Aim for 81 to 85% of your THR.
3. Using your brain
An even cheaper tool is using your brain to pace yourself. A simple way to do this is with an Rate of Perceived Exertion (RPE) scale. This is an intensity scale between 1 and 10. Where 1 out of 10 feels like your easiest effort level and 10/10 is your hardest.
Race target time: Sub 5 hours > Aim for 6 out of 10 effort.
Race target time: 5 to 6 hours > Aim for 5 out of 10 effort.
Race target time: 6 to 8 hours > Aim for 4/5 out of 10 effort.
Riding at the right intensity takes discipline and courage, especially when other people are overtaking you. But it really works. Later on in the race, you’ll find yourself passing those who passed you earlier. It’s really satisfying.
Half Distance Triathlon Run Pacing
If you paced the swim and bike sensibly, you’re in with a fighting chance of running well. However, you’ll still be very tired by the time you hit T2. After all, you’ll have been racing for between 3 and 6 hours by now, so don’t expect to run like you would for a standalone half marathon. Realistically you should be aiming for an intensity that’s similar to or slower, than your full-marathon pace.
The best ways to measure your intensity during the run are pace, heart rate, and RPE. Pace is a great measure if you’re on flat terrain without much wind, while heart rate is useful if it’s hilly or windy. You might even find that RPE is the best way to measure your pace because it encourages you to listen to your body.
Here are my run pacing guidelines. If you prefer, you can use the triathlon pace calculator on this website.
Half Distance Triathlon Run Pace Guide
Here are three ways I recommend you pace a half-distance run split, such as an IRONMAN 70.3 or middle-distance triathlon.
1. Using a heart rate monitor
Like on the bike, you can use a heart rate monitor to identify your Threshold Heart Rate (THR), your mean average heart rate for a one-hour running race at your best effort.
Race target time: Sub 5 hours > Aim for 90 to 92% of your THR.
Race target time: 5 to 6 hours > Aim for 87 to 89% of your THR.
Race target time: 6 to 8 hours > Aim for 85 to 87% of your THR.
2. Using a smartwatch
A smartwatch or GPS device can provide you with your running speed or pace. This pace is usually displayed in minutes per kilometre or minutes per mile. To identify your Threshold Run Pace (TRP), simply use the mean average pace for a one-hour running race at your best effort.
Race target time: Sub 5 hours > Aim for 90 to 91% of your TRP.
Race target time: 5 to 6 hours > Aim for 87 to 89% of your TRP.
Race target time: 6 to 8 hours > Aim for 86 to 87% of your TRP.
3. Using your brain
Just like on the bike, you can use your Rate of Perceived Exertion (RPE) during the run. Create an intensity scale between 1 and 10. Where 1 out of 10 feels like your easiest effort level and 10/10 is your hardest.
Race target time: Sub 5 hours > Aim for 5 out of 10.
Race target time: 5 to 6 hours > Aim for 4 out of 10.
Race target time: 6 to 8 hours > Aim for 3.5 out of 10.
The best thing about these guidelines is that they stop you from going too fast. And you might find that from halfway through the run, you can just ignore them. Because, by that point, it’s important to listen to your body.
With half-distance triathlons, even small differences in your power, pace, or speed can make a big difference to your overall fatigue. It can be tempting to race hard or overtake people, but you should run your own race. And remember that the downsides of starting too fast are far greater than the downsides of starting too slow.
