The Functional Threshold Power (FTP) training value was invented by Hunter Allen and Andrew Coggan, who are regarded as the pioneers of training with power meters. They defined the FTP as the highest continuous performance that can theoretically be maintained for 60 minutes without fatigue setting in.
The definition sounds abstract at first, but it has a fundamental meaning for training: it marks the point at which the body is just able to break down the lactate produced. Above this threshold, lactate accumulates in the muscles and you fatigue within a few minutes.
In contrast to the various threshold values used in laboratory diagnostics - such as the lactate threshold or anaerobic threshold - the FTP offers a practical, standardised value that can be determined without complex blood analyses. While scientists have developed over 30 different definitions of "threshold", the FTP provides clarity: one value, one test, one clear basis for training.
The real strength of the values from an FTP test: it is a basis for all training zones. Once you know the threshold power, all intensity zones can be defined as percentages of FTP. Basic endurance at 65 per cent of FTP, threshold training at 95-105 per cent, VO2max intervals at 110-120 per cent.
FTP test warm-up
The test protocol developed by Hunter Allen has established itself as the gold standard because it is practical yet precise. The test begins with a standardised 20-minute warm-up at 65 percent of the estimated FTP - a relaxed basic endurance pace that supplies the muscles with blood without straining them.
Three one-minute intervals of fast pedalling at 100 rpm activate the neuromuscular system and prepare you for the upcoming exertion. After five minutes of relaxed riding, the first highlight follows: a 5-minute maximum test. Here you have to give it your all, but with strategy. Don't start too aggressively - you need a little reserve for a final spurt in the last minute. This test fulfils two functions: It prepares the legs for the main effort that follows and at the same time provides the VO2max performance (training zone 5), which becomes important for later training planning.
FTP test over 20 minutes
After ten minutes of regeneration at a relaxed pace, the core of the test begins: the 20-minute time trial. The choice of route is crucial for success. Ideally, you should choose a flat route without traffic lights or junctions that allows you to maintain a constant power output over the entire distance. For beginners, a slightly uphill route or a route with a headwind is recommended - this forces you to pedal continuously instead of "cheating" in the slipstream or freewheeling. The test can also be completed indoors on the Smart Trainer. Advantage: no crossings, no traffic lights, no danger from cars. The pacing strategy determines the success or failure of the test. The most common mistake is to start too aggressively. Start the first two minutes about 10-15 watts below your estimated personal FTP and then increase continuously. The aim is to achieve the highest average wattage over the entire 20 minutes. In the last three minutes you should give it your all. If you still have reserves in this phase, your pacing was too conservative. The perfect test ends with the feeling that you couldn't have ridden a second longer. The test is followed by 10 to 15 minutes of relaxed riding to reduce the accumulation of lactate.
Evaluation of the test
The evaluation is very simple: you determine the average power over the entire 20 minutes and subtract five per cent. For example, an average power output of 305 watts results in an FTP of 290 watts (305 × 0.95 = 289.75, rounded up to 290 watts). This five per cent rule has a physiological background: as the FTP is defined as a 60-minute value, but the 20-minute test includes a higher anaerobic capacity, this percentage must be corrected. However, the correction is individual: athletes with a high anaerobic capacity (typically sprinters or track cyclists) may need to subtract a little more, while purely aerobically orientated long-distance cyclists need a little less.
Common mistakes and how to avoid them
The biggest mistake lies in the pacing: too many athletes start euphorically and then collapse. Another critical point is the choice of route. Traffic lights, roundabouts or technical descents distort the results considerably. Irregular test repetitions are just as problematic - if you only test every six months, you lose touch with your current form. Standardised conditions are essential for comparable results. If possible, you should test at the same time of day, after similar preparation and in comparable weather conditions.
Integration into training plan
The FTP test is more than just diagnostics - it is a high-quality training session that triggers specific physiological adaptations. The 5-minute maximum load trains the VO2max capacity, while the 20-minute time trial works directly on the threshold. Ideally, the FTP test should take place after a relaxed week.
Alternatives to the FTP test
The FTP test according to Coggan and Allen is characterised by its simplicity - but there are alternatives. Science offers the concept of critical power, in which a straight line is laid through the data points using several short maximum tests (3-30 minutes). The slope of this straight line theoretically corresponds to the FTP. The problem is that if the tests are too short, this method significantly overestimates the actual continuous metabolic performance. Modern software such as TrainingPeaks WKO4 offers another alternative: the modelled FTP (mFTP). This is calculated using the training data from the last 90 days and can provide precise estimates. For beginners, the mFTP offers the advantage of quick orientation without a formal test. The quality depends heavily on the data basis. If there are no hard workouts in the last three months, the mFTP will be too low. Conversely, a single best performance that falls outside the 90-day window can lead to drastic jumps.
Why the FTP test remains unbeatable
Despite all the technical sophistication, the practical test remains the measure of all things. "Testing is training and training is testing" - Coggan and Allen's motto. An FTP test is also a high-quality training session that triggers specific physiological adaptations. You not only learn about your current performance, but also train the mental toughness required for competitions and hard training sessions. Regular tests every six to eight weeks not only show progress, but also help to recognise overtraining or stagnation at an early stage. Especially in the build-up phase, values can change quickly - beginners often experience jumps of 20-30 watts within a few months, while experienced athletes have to fight for small improvements.
Conclusion: More than just a number on the display
The FTP test is the cornerstone of successful, measurable training. The determined threshold power transforms the watt meter from an expensive toy into a precise training tool.
