You have a power meter.
You have a Functional Threshold Power score.
You have a power zone list for training.
Now what should your race power be?
This is a guide for Ironman and half Ironman events you can used based off a percentage of your Functional Threshold Power (FTP) or critical power score.
Looking at your predicted race finish time, you can use these percentages to help guide your training and what power you plan to hold for your race. Many athletes simply pick a number they see often when they feel good on their long rides. This doesn’t translate too well come race day.
These hours are total race times and not bike split time. The percentage is a percentage of your FTP
Half Ironman Power:
- 3-4 hours = 83-85%
- 4-5 hours = 81-83%
- 5-6 hours = 79-81%
- 7+ hours = 75-77%
- 8-9 hours = 78-80%
- 9-10 hours = 76-78%
- 10-11 hours = 74-76%
- 11-12 hours = 72-74%
- 12-13 hours = 70-72%
- 13-14 hours = 68-70%
- 14-15 hours = 66-68%
- 15-17 hours = 64-66%
To use nice simple maths, if my FTP was 300 watts and I wanted to race a Half Ironman in 4-5 hours and a full Ironman in 9-10 hours, my racing power would be:
- Half Ironman: 243-249 watts
- Ironman: 228-234 watts
For both half Ironman and Ironman, riding up hill at these power watts will be too low however you don’t want to go over threshold. so bringing it up to threshold but not over threshold.
With downhill, big gear and peddle softly.
Hope these numbers help.
This is great insight, thanks!
However how do I measure this during a race apart from the bike ride?
Hi Stuart, Thanks mate.
If you shoot me an email firstname.lastname@example.org and will help with greater detail.
Love these, very practical and useful. Although I am wondering the basis, and based on that basis if I can extrapolate to longer events. Like say a 20 hour or 24 hour event; the same rule(s) should apply, whatever they are. Thanks!
I would say something like a 24hr event, you would really need to stay within your fat burning zone as much as possible so an event like that, I would guess if we were talking power, keeping watts around the 65% of FTP and never going over 100% of FTP on hills.