Functional Threshold Power: Ins and Outs of arriving at your number!
Before we start throwing numbers around let’s start with a simple definition of Functional Threshold Power (FTP) as it pertains to the bike: The amount of power, expressed in watts, a rider can hold for 60 minutes. Pretty simple sounding but a little tough to nail down because a) it is not a static number and b) it isn’t easy to test for. This article will discuss testing methods and what this number means to your training. Our next article will delve into how to use this number to train and race.
FTP has been in use for nearly 25 years but has really gained steam in the past 5 years as the cost of power meters has dropped. Reliable meters not only mean you can find solid numbers but make it easy for you to use that number in everyday training. By discovering and using your FTP in training you can measure your progress more precisely, take the guesswork out of your future workouts and it gives you a pacing guide for races.
There are several reliable tests to help you discover your FTP. Obviously riding hard for an hour would be the first thought. But riding HARD for an hour is less than fun and riding for an hour during training and riding for an hour at a race are two different things. The competition induces better numbers then you can produce on your own, plus after an hour all out you are going to need some serious recovery. Joe Friel, the godfather of FTP, recommends the 30-minute test to help produce a more reliable number. He theorized pushing really hard for 30 minutes is something you can wrap your head around even without competition and it is reproducible. The 30 min test, as with all FTP tests, must be proceeded by a solid warmup and should also come after a recovery day.
Another acceptable test is the 20 min FTP test developed by Andrew Coggins (who is well known for you slowtwitchers). This effort has become more commonly used because it’s even more reliable, with regard to reproducibility, and something that can be done monthly. This test requires that you record the average watts over 20 min and then minus 5% to come up with your FTP. Once the athlete has done this test a few times and becomes familiar with the effort the numbers become truer and truer.
Last on the list both in use and reliability is the 8 x 2 min FTP test. Although this test can be used in between bigger efforts if you are not sure where you stand fitness-wise. It requires a warm-up and then 2 all-out efforts of 8 min separated by a 5 min recovery spin. 10% is taken off the average to come up with a working FTP number. This test, as with all FTP tests, has one important caveat: Outdoor FTP, because of distractions such as steering, braking, and your surroundings, take your mind off the pain and produce you higher results. Because of this, you should always have an outdoor FTP done to use for race pace purposes.
So once you have your number it’s good for the year, right? Well no. FTP can drop over just a week of no training. It can go up after several weeks of hard training. It is a moving target for sure and that movement can have an effect on your training. If you are coming back from an injury and try to workout at your previous FTP you are probably overdoing it, been working hard on your training then you better adjust that FTP up to get the most out of your workouts. TrainingPeaks and your coach are your best friend in keeping this number in line with your fitness.
A correct FTP is the most reliable metric you can use for your bike training. It removes the heart rate as a training metric which can be super variable. It gives an accurate picture of your current fitness compared to previous history and where you to go. It provides a road map for setting up your workouts, which we will describe in the next article, and race pace watts can be determined and it can make walking the run a thing of the past!