Setting Your FTP and Training Zones
Functional Threshold Power is the single number that anchors your entire training structure. Every zone you train in — from easy aerobic work to maximal efforts — is derived from it. If your FTP is inflated or stale, you'll train too hard on easy days, too easy on hard days, and wonder why you're not improving.
This chapter covers how to establish a reliable FTP, how to convert it into zones, and how to maintain both over time.
What FTP Actually Represents
FTP is the highest average power output you can sustain for approximately one hour. It sits at the ceiling of your aerobic capacity — above it, lactate accumulates faster than you can clear it, and the effort becomes unsustainable within minutes.
In practical terms, FTP is a proxy for your lactate threshold. It's not a perfect measure — individual physiology, pacing skill, and fatigue all affect any single test result — but it's repeatable, measurable, and directly actionable for zone-based training.
See the full definition in the FTP glossary entry.
How to Test Your FTP
There are several valid protocols. Choose one and stick with it — consistency in testing method matters more than which method you pick.
The 20-Minute Test
This is the most widely used field test. After a structured warm-up with some short hard efforts to prime your system, ride as hard as you can sustain for 20 minutes. Take 95% of that average power as your FTP estimate.
The 95% correction exists because most people can hold slightly more for 20 minutes than they could for a full hour. Pacing is critical: starting too hard produces a blow-up, not a useful number.
Warm-up structure:
- 10–15 minutes easy riding
- 2–3 short efforts (around 30 seconds) at high intensity to open the legs
- 5 minutes easy before the test effort begins
The Ramp Test
The ramp test uses incrementally increasing power until you can no longer hold the target. Your FTP is estimated from your peak one-minute power using a fixed formula (typically 75% of that peak).
Advantages: shorter, less mentally demanding, less sensitive to pacing errors. Disadvantage: it measures a slightly different physiological quality than a sustained 20-minute effort, and the estimate can be less accurate for riders with atypical power-duration curves.
The 60-Minute Test
The most accurate method — ride at maximum sustainable effort for a full hour. Average power equals FTP directly, no correction needed. Few athletes use this regularly because it requires perfect pacing, high motivation, and significant recovery time.
Estimating Without a Formal Test
If you have existing ride data, the FTP estimator tool can extract a likely FTP from your best recent efforts. This is useful between formal tests or when you're returning from a break and want a starting point before committing to a full test.
Building Your Training Zones
Once you have an FTP number, zones are calculated as percentages of it. The most common system used in power-based training uses seven zones:
| Zone | Name | % of FTP | Physiological Target |
|---|---|---|---|
| 1 | Active Recovery | < 55% | Promote recovery, minimal stress |
| 2 | Endurance | 56–75% | Aerobic base, fat oxidation |
| 3 | Tempo | 76–90% | Sustained aerobic effort |
| 4 | Threshold | 91–105% | FTP development |
| 5 | VO2 Max | 106–120% | Cardiac output, maximal aerobic power |
| 6 | Anaerobic Capacity | 121–150% | Short, high-power efforts |
| 7 | Neuromuscular | > 150% | Sprint, peak power |
Some coaches and platforms use a five-zone model. The underlying physiology is the same — the boundaries shift slightly depending on how zones are grouped. What matters is that the percentages are anchored to an accurate FTP.
How to Use the Zones
Zones are not targets to hit every session. They're descriptions of physiological stimulus. A Zone 2 ride is valuable because of the duration spent at that metabolic intensity — not because you briefly touched 60% of FTP before surging to 85%.
Key discipline:
- Zone 2 work requires resisting the urge to push harder. Many athletes chronically ride Zone 2 at the top end or into Zone 3, which adds fatigue without adding the specific adaptation.
- Threshold work (Zone 4) should feel controlled and uncomfortable — not a desperate survival effort. If you can't complete the intervals as prescribed, your FTP is set too high.
- Zone 5 and above should be used sparingly and with clear intent. These are high-fatigue, high-adaptation efforts.
For a deeper look at how zones fit into structured blocks, see the training with power hub.
Common Mistakes When Setting FTP
Testing when fatigued. FTP tests require freshness. Testing at the end of a training block, or after a hard week, will produce a number that's artificially low. Schedule tests after two to three easy days.
Overestimating in the 20-minute test. Athletes who go out too hard and fade produce a skewed average — lower than they could have held with even pacing. Practice pacing before you test.
Setting FTP from a race effort. Race adrenaline, drafting, and crowd effect can produce power outputs that aren't repeatable in training. A race performance can inform your FTP estimate, but treat it with some skepticism.
Never retesting. FTP changes with training. A number set at the start of a build block may be significantly lower than your actual capacity by the end of it — meaning you've been undertraining for weeks.
How Often to Retest
For most athletes in structured training, retesting every six to eight weeks is appropriate. Retest:
- At the start of a new training phase
- After a significant fitness-building block
- After illness or a training break of more than two weeks
- When prescribed workouts feel consistently too easy or impossible to complete
Between formal tests, use the FTP estimator to check whether recent ride data suggests your number should be adjusted.
Keeping Zones Current
Zones only work when they're calibrated to your current fitness. A single accurate FTP test followed by months of unchanged zones is common — and counterproductive. Build the habit of treating FTP as a live number, not a fixed identity.
When FTP increases, recalculate all zones immediately. A 5% gain in FTP shifts every zone boundary — what was Zone 4 training may now be Zone 3 work at the same absolute wattage.
Get this right, and every training session you do has a defined purpose and a measurable target. That's what power-based training is built on.