In a previous post I spoke about how important it is to have an accurate Functional Threshold Power (FTP) to properly set training zones and track Training Stress Score accurately. Today I figured it might be wise to talk about two of the most popular ways to test for your FTP; the 20 minute Time Trial Test and Ramp Test.
Historically the most common way to test for your FTP was to do the 20 minute Time Trial effort that would leave you laying on the floor questioning why you even participate in this sport. In recent years TrainerRoad and Zwift have popularized the Ramp Test which only requires about 5 to 8 minutes of suffering. Based on the last two sentences this seems like it should be a short article; you choose the least amount of suffering and do the Ramp Test of course. Well unfortunately depending on the type of athlete you are it might not be that simple.
Let’s remember what it is we are testing for, Functional Threshold Power is basically the power you can maintain for 45 to 75 minutes. If you haven’t read my previous post about FTP and would like a more in-depth understanding you can do so here. The best way to find out your 1 hour power would be to ride as hard as you can for 60 minutes BUT that would be absolute tourcher to ask an amature athlete to do that outside of a race. So that leaves us with the more humane versions of testing using either the traditional 20 minute TT or the Ramp Test.
How are the tests performed?
The 20 min TT Test is an all out effort for 20 minutes done either outside on a safe road or indoors on a trainer NOT on ERG Mode. After a proper warm up the athlete will then go as hard as they can for 20 minutes; at the end of the 20 minutes you take 95% of the average power of the 20 min test section to get your current FTP setting. As an example if the athlete’s average power for the 20 min test was 300 watts the resulting FTP would be 285 watts.
The Ramp Test is done indoors on a trainer using ERG Mode. This test is done slightly differently between TrainerRoad and Zwift but the concept is the same. What is being tested is your maximal 1 minute power at Vo2 max and then taking a percentage (about 75%) of that power. The test is performed by starting out doing a 5 minute warmup and then the power will increase every minute until you can not continue any longer; you simply just can’t turn the pedals anymore. This test requires you to really suffer for about the last 5-8 minutes when your HR is at its max and your legs are burning. As an example if your highest 1 minute power during the test was 380 watts then you would be awarded an FTP of 285 watts. Now keep in mind that the athlete didn’t just hold 380 watts for a minute; that athlete most likely spent the last 6 minutes of the test over 330 watts with the last full minute of power being at 380 watts.
What is each test really testing for?
What we are trying to solve for is your Functional Threshold Power (FTP); which is the power that corresponds closely to your lactate threshold. Each of the tests get to this number by testing different markers to predict your FTP. As mentioned above the Ramp Test is using your power at Vo2 max; data has shown that our FTP is “typically” around 75% of that value. The traditional 20 minute Time Trial is more closely looking at your actual power at the lactate threshold. When the Time Trial test is performed properly with even pacing across the 20 minutes with either a slight rise or decrease in power (no big power spikes) we get a great sense of where that line between lactate accumulation and lactate clearing is. The reason we take 95% of that number is because during the 20 min test you are actually riding above your lactate threshold for a bit of time accumulating lactate and then riding just below your lactate threshold for a bit to clear that lactate. So by riding at a slightly reduced power will limit the lactate accumulation allowing you to maintain that effort for 45-75 minutes. I would have to give the test accuracy edge to the 20 min TT test as it is testing your power near your lactate threshold compared to the Ramp Test which is backing into that number by using power at Vo2 max.
Which test should you do?
As with almost any question the answer is, it depends. There are a number of reasons to perform one test over the other but let’s focus on the most important one; what type of rider are you? Are you the athlete who needs/want to be able to maintain a long steady state effort like a triathlete, Gran Fondo or long breakaway rider or are you more of a punchy rider that likes to be a thorn in the side of your mates on the weekend group rides, mountain biker or road racer? If you are the triathlete type then the 20 min TT is without a doubt the best option; and if your riding needs tend to be a bit more punchy than the Ramp Test is perfectly fine.
Another way you can choose which test you should take is to look at the type of workouts you have been doing in your training program. If your training program includes a lot of workouts with 10-20 minute efforts in Zone 3 & 4 (80-105% FTP) then you are certainly best doing the 20 min TT test. If your training program includes more efforts of 1-8 minutes in Zone 4 & 5 (95-120%) than you might actually be better off with the Ramp Test. The reason we test is to see if we are improving as an athlete; we improve because of our training program so it only makes sense to test yourself in the manner that you prepare yourself.
Bottom line is if you are still unsure of which test to perform then I would recommend that you do the 20 min TT test. If you really wanted to be sure you could always follow it up with a Ramp Test a few days later. The great thing about the Ramp Test is that you don’t really have to be rested to perform it so you can mix it in at any time. The 20 min TT test should be done during a rest week so the body is ready to perform similar to a race effort. By performing both tests you may also learn a bit more about what type of rider profile you are and where you need to improve to see even large FTP gains.
Enjoy the suffering.