Functional Threshold Power (FTP) has become the standard for testing cycling performance in recent years. It has not become the standard because it is what professionals or sports scientists recommend, but because it is practical for most non elite athletes. The standard 20min FTP test was developed by Andy Coggan as a means of producing a reliable and practical test of sustainable power. The test involves an extensive warmup which includes a hard 5min effort. This puts some slight fatigue into the legs so the effort is more realistic and similar to a real life scenario. The average power for 20mins is then recorded and 95% of this average is taken as the FTP number.
Many individuals will be able to complete an FTP on a turbo trainer which reliably calculates and records power. The test can also be completed outside if you have a power meter but it is often difficult to find an unbroken 20min stretch of road with an even gradient. There are variations of the FTP test. A ramp test, a 2X8min test and the 30min test all yield similar results.
What does an FTP test give?
The theory of FTP is that it reflects your one hour sustainable power. This one hour power number is tightly associated with the anaerobic threshold or Onset of Blood Lactate Accumulation (OBLA). Above this intensity, sustainability of effort is massively reduced as lactate accumulation quickly occurs and fatigue rate increases dramatically. For this reason we see the effort at OBLA as being our critical performance indicator as it is what we can manage before significant fatigue. Increasing our ability at this point usually dictates performance ability. As a result, our effort at OBLA or FTP is the number we base our training strategy around.
Problems with FTP
While FTP is practical and very common it has several issues which people may neglect to factor in. Firstly, FTP is estimated at 95% 20min average power. In reality it is anywhere between 85 and 95% which is a huge range. Many individuals are also quite anaerobic and tolerate short bursts of effort quite well; this can inflate an FTP test score. Usually this is the case with less aerobically trained amateur athletes. These two factors can mean that training numbers are grossly overestimated when based on an FTP test. Individuals may really struggle to hit targets prescribed in workouts.
FTP is a very good indicator of 20min efforts, but it is hard to extrapolate the results to performance over longer or shorter distances. FTP will not help prescribe one minute all out sprint efforts or a 180km Ironman distance. Despite this, many training for those type of events will still try to use FTP, where other tests may be more appropriate.
How to use FTP
FTP is a performance test which can give a very good snapshot of an individual’s current ability. Using it to dictate a training plan must be done with care and diligence. In most cases underestimating FTP yields better results as it ensures the body can cope and respond to training intensity. The type of individual and training goals should also be considered. An Ironman athletes FTP number is pretty irrelevant to training and submaximal efficiency should be the focus of attention during assessments. Similarly a sprint type cyclist may look more at sprint repeatability and fatigue rate as a more relevant indicator. FTP is more suited to short distance time trials and Sprint Triathletes. The main concern is that you don’t pay too much attention to just lifting FTP numbers as this can neglect aerobic development. The quickest way to increase FTP is to increase threshold tolerance. This does little for overall fitness and in the long term is not massively beneficial.
Alternatives to FTP
As discussed above, there are variations of the test. 30min and hour sustained efforts may also be used to gauge ability. The gold standard test is completed by gathering blood lactate samples to precisely establish the breaking points between physiological processes. This isn’t as practical but there are an increasing number of service providers offering this test.
One should examine the ability they are trying to develop and use an appropriate assessment. A good coach will have a number of different tests that can be utilized to create a more complete picture. In doing so they will be able to prescribe training with much greater accuracy.
If you are going to base your training on an FTP number, be conservative with the zone prescription. As a precaution reducing the number by 5-10% usually ensures you are more accurately within your physiological zones. Paring power with heart rate can be an excellent indicator of accuracy. While heart rate can be variable it is usually a good indicator of your body’s daily readiness to train and helps avoid over taxing your body. We have discussed this in a previous article here.
When in doubt look to those more experienced. Good coaches will be happy to offer a bit of advice without asking you to commit to their services.