Subtitle: You have the fitness. Now you need a plan. Here is how to use Intensity Factor (IF) so you do not blow up before the finish line.
Training is about building the engine. Racing is about managing fuel. One of the most common mistakes amateur athletes make is racing by feel in the first hour, then cracking in the last hour.
The solution is Intensity Factor (IF).
IF contextualizes Normalized Power (NP) against Functional Threshold Power (FTP). An IF of 1.0 means you held FTP for an hour. An IF of 0.7 means you held 70% of FTP. It gives you one comparable number to plan effort across durations.
The problem with feel
On race day, you are tapered, caffeinated, and full of adrenaline. 300 watts can feel like 200 watts. If you pace by feel, you can burn through glycogen in the first 90 minutes. IF provides an objective ceiling to keep ego in check.
Pacing guidelines by duration
Based on classic power levels and Enduroco athlete consensus, these are practical IF targets:
1. The criterium (45-60 mins)
- Target IF: 0.95 - 1.05
- Strategy: full gas. There is no smooth pacing, only survival. Surges above threshold are expected.
2. The road race / gravel sprint (2.5 - 4 hours)
- Target IF: 0.80 - 0.90
- Strategy: this is the sweet spot of racing. Burn matches selectively and conserve in draft whenever possible.
3. The gran fondo / century (4 - 6 hours)
- Target IF: 0.75 - 0.80
- Strategy: high Zone 2 / low tempo. It should feel too easy early. That is the point.
4. The ultra (Leadville, Unbound, Ironman) (8 - 12+ hours)
- Target IF: 0.65 - 0.70
- Strategy: pure endurance. Keep first-half and second-half IF close. Large divergence means pacing failure.
The new AI FTP wrinkle
With tools like Enduroco AI FTP detection, FTP can fluctuate and may feel different than a 20-minute-test value.
- Trust but verify: do a validation ride (for example, 2 hours at target IF).
- Heart-rate check: if target power drives HR 10 bpm higher than expected for that zone, back off.
Power is primary, but HR is the safety valve for heat, altitude, and race-day nerves.
Conclusion
A number is just a number until you test it. Use IF targets as a starting framework in long training rides. If you finish strong, you are close. If you crawl home, adjust your target (or FTP) down. Race smart, not just hard.