If you’re new to cycling training, you’ve probably never taken an FTP test. Heck, you probably have no idea what an FTP test even is! Let’s cover the basics of FTP, and options for testing it on Zwift.
What is FTP?
FTP is short for Functional Threshold Power. It’s the most commonly-used metric of fitness for cyclists, and measures the maximum power you can hold for longer durations. Going above your FTP will result in blood lactate levels increasing until you “blow up”, but if you’re fresh and well-fueled you should be able to ride at FTP for anywhere from 40-60 minutes.
While FTP is often described as the max power you can average for 60 minutes, that is not how it was actually defined by those who pioneered its use. Andrew Coggan defined it as, “The highest power that a rider can sustain in a quasi-steady state without fatiguing.”
Why Test Your FTP?
On Zwift, knowing your FTP is important for two reasons:
- Your FTP setting determines the power requirements for intervals in structured workouts. If your FTP is set too low you won’t get an adequate workout, and if it’s set too high you won’t be able to hit your power targets.
- Most Zwift races are categorized by FTP in watts per kilogram (your FTP divided by your weight in kg – a 300W FTP for a 75kg rider would be a 4 w/kg FTP). If you don’t know your FTP, you may jump into a category of riders well under or over your fitness level. (Good news – Zwift’s new category enforcement features, once rolled out across the platform, should prevent riders from joining too low of a category.)
How To Test Your FTP on Zwift
Here’s the simple 4-step process used by most Zwifters:
- Kit up, boot up
- Pick a test from the workout options under Training>FTP Tests
- Follow the instructions on screen, destroying yourself in the process
- If your FTP increases, share it on Zwift Riders. If it does not, never mention this test to anyone. 🙂
Let’s take a closer look at the FTP test options Zwift provides.
4 FTP Test Options on Zwift
The original “standard” FTP test, this one is also the longest, at 73 minutes. It includes 3 short ramps, plus a 5-minute interval over FTP which is meant to take the snap out of your legs so your 20-minute test uses less anaerobic power and more aerobic power.
In this workout, the 20-minute test is all that matters. Your FTP result will be computed as 95% of the power you average during the 20-minute free ride interval.
FTP Test (Shorter)
A shortened version of the original test, this one only lasts 45 minutes but still includes the key components. Just one ramp effort, and a slightly harder 5-minute block, but you’re still going to do an all-out 20-minute effort. The warmup and cooldown periods are significantly shortened.
The ramp test starts easy, then simply increases your wattage by 20W every minute until you can’t pedal anymore. It’s a much shorter test than the two FTP tests above, and you don’t have to worry about pacing yourself for a 20-minute effort. Just stay seated and pedal for all you’re worth, until you can’t pedal anymore! Typically the ramp test feels very easy at the start, but gets really hard in the last 5 minutes.
Zwift will calculate your FTP once you stop pedaling. Your FTP Is calculated as 75% of the highest 1-minute power averaged during the test. If your new FTP is higher than your old one you’ll get a popup that says a “New FTP set!”
Ramp Test Lite
If you weigh less than 60kg/132lbs, you’ll want to take the “Ramp Test Lite” instead of the standard ramp test, because this test starts at a lower wattage and increases by only 10W per minute. It’s a ramp test made for lighter riders with a lower FTP.
Which FTP Test is Best?
Everything about the ramp test is easier than the standard FTP test, but the downside is ramp tests can be less accurate, depending on your physiology. Specifically, riders with a higher anaerobic to aerobic power balance may have their FTP overstated by a ramp test.
On the other hand, the standard FTP test and its 20-minute all-out effort is very challenging, both mentally and physically. Additionally, newer riders will struggle to properly pace a 20-minute effort (they often blow up early).
Both styles of tests have their pros and cons, but generally speaking if you are a beginning cyclist and/or you want a quicker, easier test, go with a ramp format. If you want higher accuracy, and have the experience to pace yourself properly, go with the 20-minute format.
If you’ve never taken an FTP test, we recommend using the ramp test first. This will give you a fairly accurate FTP number, which you can use to pace yourself for the 20-minute test next time.
Automatic FTP Detection
Many Zwifters get FTP Increase notes in Zwift without ever taking an FTP test. How? Because Zwift is always measuring your best 20-minute power as you ride, and if 95% of your best 20 minute wattage exceeds your current FTP setting in game, Zwift will alert you to a new FTP.
Example: your FTP is set to 200W in game. You do a short Crit City race, and your best 20-minute power during that race was 220W. Zwift will alert you to a new FTP of 209W (220 * .95) and update your saved FTP value when you save your ride.
While this method of FTP detection doesn’t quite match the standard testing protocol, it’s a simple proxy for an actual test.
Most cycling data platforms will compute an estimated FTP based on your ride data, even if you never take an FTP test. These calculated FTP figures are arguably more accurate than an FTP test, but it depends on how they’re calculated and what sort of efforts you’re feeding into their algorithms. Some of these platforms are free, while others may carry fees. Popular platforms include intervals.icu (free, plugs into your Strava data), Xert, and WK05 software.
Questions or Comments?
I do the ramp test around every 4-6 weeks as a measure of whether my training is producing results. For me, after the initial minutes, once the resistance goes above my FTP, it works out as just a few minutes of pain going quickly from easy to being unable to turn the pedals! The problem with the automatic detection is that it doesn’t know whether you were seated or not whereas the FTP tests are supposed to be seated tests. I can get an artificially high suggested FTP riding up the Alpe because of time spent out of the saddle.… Read more »
The other choice is Tempus Fugit itt or another moderate length flatter itt route.
FWIW, I did the ramp test lite last year and it just ended at 250 watts with a result of something like 187 watts FTP. Maybe they changed it since then?
no 187 is 75% of 250
Sounds like you “topped out” the Ramp Test Lite, since it ends at 250W. You should take the standard ramp test.
whenever I do an FTP test I just turn my FTP down and then go all-out for 20 minutes up the alpe since I get too bored on the workout FTP tests, and I still get arguably better power averages and I get heart rate average.
Not a terrible way to do it, but as mentioned above, the standard protocol includes a hard 5-minute effort prior to the 20-minute one, to drain some of your anaerobic power. Without doing that, your method probably overstates your FTP a bit.
If your new ftp falls out lower than the one you had earlier – how do you see the result then (no pop up then I guess) ?
I question the results of the ramp test for me. At age 63 when my heart rate got up to 165 (I think I was at about 220 W) I pulled the plug. My legs still had more in them but I prefer to keep my heart intact. A few years ago due to concerns over possible heart problems I took a treadmill stress test. My heart rate max out at 185. This makes me believe I have a less than accurate FTP of 159. I did do and really appreciated the 12 week training program that Zwift has for… Read more »
So you pulled the plug before your heart rate got too high, so you question the results of the FTP test? I would too, since it sounds like you didn’t put in a max effort. Better safe than sorry, perhaps, but yeah, you won’t get an accurate FTP assessment without going for your max effort on the ramp test.
Thanks for being a Players Union member, Rob! 🙂
Either zwift or wahoo bungled my attempt at an ftp test.
I know how it works, erg mode, etc.
As soon as the ramp tets began 0 resistance, despite having a comfortable one just before, meant cadence was 130+ and absolutely no power.
Result was 200w down on “real” ftp. Waste of time, wahoo and zwift both point finger at each other.
Just stick with auto stuff.
Me and a friend have been having a discussion on whether changing your smart trainer had a difference on FTP. He has Elite and I have Wahoo kicker core. Do you have any thoughts on this?
When we look at the workout graphs, his power line is very peak/valley, even on ERG mode. Mine, on the Wahoo is completely flat for each power output at specific power numbers on ERG mode.
I hated that about my Elite Direto. I do periodic 60 minute FTP tests in ERG mode, using the FTP bias adjustment on the companion app to fine-tune resistance. If ERG was set to 250, the Direto would constantly fluctuate between 235 and 265 about every 10 seconds. It definitely felt harder, but when I duplicated the test with my wife’s Kickr Core, I would get essentially the same FTP result, even though Kickr Core could hold the resistance very steady. So (based on N=1,) I don’t think it actually affects the results if you are relying on the ERG… Read more »
Where do you find your current FTP on Zwift? I did the ramp, it displayed it for about 5 seconds, and now I can’t find it anywhere…?
If you go into the workouts menu (and maybe you have to select one I can’t remember off hand), it will be in the bottom right. You can manually change it there as well.
As a complete newbie, should I do an FTP test before I start any type of training plan?
Yes! I’d recommend the ramp test… it’s the simplest way to get a good estimate of your FTP.
Does anyone know for sure if for the FTP tests do we sit, stand or both? ZwiftPower doesn’t specify state one way or another. ZwiftPower does specifically say for the Ramp to sit the whole time.
At regular intervals the prompts are to sit at all times
Hi everyone, i have a question, why is it taking 95% of best 20 minute wattage?
Thanks in advance for answer.
Because 95% of your 20 minute maximum power is hypothetically what you could sustain for 1 hour, and therefore your FTP.
Hi! My old FTP is to high so yesterday I did a new test and got a new result (lower;) damn you Covid) but the new result wasn’t saved in Zwift. And I don’t know how to se or set it manually.. tips?
Set your FTP on the same screen where you edit your profile (name, weight, etc). You can also change it from the workout picker screen (bottom-right).
For me the best way to assess FTP is to do the Road to the Sky/ Alpe…
It gives you your time and average power for the climb, which for me is close to an hour….
Then repeat a few days later, with the aim of sustaining the average, or slightly higher…a few repeats and you’ll soon learn the best average you can sustain.
Eric, Excellent article, really cleared up the difference in FTP tests. So, decided to do the short FTP test in place of the ramp test. My FTP last year was 240 with the ramp test, this year 178, but I’m not surprised. The ramp test rewards heavily anaerobic effort (think strength, weight lifting, HIIT, and believe it or not climbing biking), whereas the short FTP rewards aerobic (my VO2 max has always been in the gutter, and think swimming, running, and most biking). I believe this year’s number is more accurate. Btw, I on occasion do Rouvy, but haven’t done… Read more »
There’s a new ‘beginners FTP-test’ in Zwift, did you write any article about that yet?
There’s something to be said about progressive increase and muscle fatigue per rider type vs. a constant wattage for 20 minutes or perhaps 5 minute over unders x4 … have a think about it an dpotentially expand this article – love your site – keep it going forever please Eric!