# Help me understand Trainerroad’s endurance zone

I’ve always been under the assumption that Z2 rides are the endurance zone. When looking through TrainerRoad’s workouts and filtering by Endurance for the zone most of the workouts never get above 58% of FTP. Every resource I can find states recovery rides are at less than 60% FTP and Z2 falls between 65-80%. Am I just wasting my time by doing the “Endurance” workouts but never actually getting into an endurance (Z2) zone?

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If you’re just using the single filter for Endurance, keep in mind the default sort is Workout Levels from low to high (from 1.0 and increasing). Flip that sort high to low WL and you will see there are MANY workouts in the 60-75% of FTP range.

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Assuming you’re talking 7 zone model, Z2 is 56-75%, not 65-80.

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56-75% based on average power, but 0.75-0.85 based on intensity factor (IF).

The latter is more relevant here, as power is almost invariably more constant when training indoors (as I pointed out when introducing normalized power, from which IF is calculated).

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Man, I don’t think I’ve broken 0.75 IF for an “Endurance” ride since I went for a 5hr solo century. Most of my endurance rides fall much closer to 0.65 than to 0.75.

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I never understood why Coggan’s ranges for zones was so different for his ranges for intensity factor. I get that IF will be higher due to the way the variability is weighted, but it still seems off.

Based on this article (Normalized Power, Intensity Factor and Training Stress Score | TrainingPeaks) he recommends up to 0.75 for a recovery ride, and up to 0.85 for endurance ride. Seems like each of these should be shifted down about 0.15 to me.

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My original training levels are skewed downwards in recognition of the variability in power when cycling outdoors, which tends to drag down the average power. I subsequently invented normalized power, which approaches the issue from a different angle.

For isopower, or close to isopower, workouts, such as is typical when training indoors, it is better to go by intensity factor (i.e., the ratio of normalized power to functional threshold power) than by average power. The two classification schemes are really independent of each other, and weren’t designed to be perfectly aligned.

Finally, keep in mind the following pithy power proverbs (PPP):

1. The training levels are descriptive, not prescriptive; and

2. They’re called levels and not zones for a reason.

(This is something that the TR paradigm gets wrong, and/or has miseducated people.)

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Sounds like you may have your FTP set too high.

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