Power zones explained: seven zones, one yardstick
Power zones split your power into seven ranges, each with its own training purpose. All hang on one number: your FTP. Here is how to read and use them.
One number, seven ranges
The common zones after Andrew Coggan are percentages of your FTP. When your FTP changes, all zones move with it. Example with an FTP of 250 W:
| Zone | Name | % of FTP | Watts (FTP 250) |
|---|---|---|---|
| Z1 | Recovery | below 55 % | up to 137 W |
| Z2 | Endurance | 55 to 75 % | 138 to 189 W |
| Z3 | Tempo | 76 to 90 % | 190 to 227 W |
| Z4 | Threshold | 91 to 105 % | 228 to 264 W |
| Z5 | VO2max | 106 to 120 % | 265 to 302 W |
| Z6 | Anaerobic | 121 to 150 % | 303 to 377 W |
| Z7 | Neuromuscular | above 150 % | from 378 W |
What each zone is for
- Z1 Recovery: very easy, for spinning out and active recovery.
- Z2 Endurance: the foundation. Long, steady rides where you can still hold a conversation.
- Z3 Tempo: brisk but steady. Useful but tiring: ride too much here and you are neither easy nor fast enough.
- Z4 Threshold: intervals of roughly 8 to 20 minutes near FTP. They raise the power you can hold for long.
- Z5 VO2max: short, hard intervals of roughly 3 to 8 minutes.
- Z6 Anaerobic: very hard intervals from 30 seconds to about 3 minutes.
- Z7 Neuromuscular: sprints of a few seconds. Peak power counts here, not duration.
The durations and goals are rules of thumb. How hard a zone feels depends on form, heat and fatigue.
Time in zone beats the average
A ride's average power hides a lot. An hour of alternating rests and intervals can have the same average as a steady endurance ride. Time in each zone shows what the session actually trained. A healthy distribution for many riders has a large share easy (Z1 and Z2) and a few hard stimuli (Z4 to Z6), with little Z3 in between.
When your FTP changes
Old rides stay rated with the FTP that applied at the time. Re-sorting them with the new FTP would shift your history. Keep this in mind when you compare time in zone over months.
In ZonePit
ZonePit shows time in the seven zones per ride. It uses the FTP that applied at the time of the ride, so later FTP changes do not distort the past. Rides that fall exactly on a zone boundary count proportionally.
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Sources
- Hunter Allen, Andrew Coggan: Training and Racing with a Power Meter (seven-zone model, percent of FTP).
ZonePit is a training and wellness app, not a medical device.