Zwift ramp test vs system 4dp

Hey all.

I just finished a 3 months training plan heading for the next one and I have issues with my ftp number .

At the beginning I had a ramp test on zwift where I got 183 ftp. Few days later I got 150 ftp on system’s 4dp test. I set the ftp for 183 through the entire plan and it was fine .

Now 3 months later, at the end of the plan I tested again on both platforms.

On zwift ramp test I got 234
On system’s 4dp I got 197

I have been wondering why the difference is so big + what should I set as my ftp for the next plan ??



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Hi @Eden_Masami, the results can be fairly different for some people. Would you say you are more of a punchy rider than a time-trialist? Even so that is quite a big difference.
Were you feeling fresh before the 4DP test?
How did you feel after the 20 min 4DP effort and did you hold a fairly steady power over that time. Ideally you hold the power fairly level and at about the 10 min point you should be thinking that there’s no way you can last out to 20 mins. But you do, just, as you collapse on the handlebars :slight_smile:
Perhaps see how long you can hold 246W (20 mins is typically 95% of FTP) after a warmup, perhaps with ERG.
Also you could try SYSTM’s Half-Monty ramp test as it accounts for some of the variation typically seen between Ramp tests and 20 min efforts.
Also remember that SYSTM uses your NM, AC, MAP and FTP results to shape your workouts.


Hi Eden, welcome to the forums!

As you have witnessed, not all fitness tests are the same. All of these tests assess your ability to hold a certain power output for a specified duration of time. Or multiple power outputs in the case of the Full Frontal or Half Monty tests.

In all cases, the durations tested are used to extrapolate an hour-long effort, our FTP. The most accurate measurement for an hour long effort would be to ride flat out for an entire hour. But that is notoriously difficult.

If you rode for 45 minutes flat out, and approximated your 1 hour FTP, you’d likely get a more accurate number than if you rode for 15 minutes and tried to approximate your hour of power.

That said, Wahoo’s fitness tests have some science behind them to help dial in that approximation more accurately. If I had to trust a single test for my actual FTP, I’d put my money on the Full Frontal fitness test, followed by Half Monty as another test which provides a reasonable approximation of FTP.

It is interesting that you’ve been able to use your Zwift FTP to complete Wahoo workouts. Kudos on that! Your latest Zwift FTP exceeds mine, so I can just imagine the suffering you’ve been able to endure!

Pacing the Full Frontal 20 minute effort is hard to do well. I’ve taken the test over 15 times and I’ve yet to feel like I’ve truly nailed every interval and especially the 20 minute one.

It’s likely your true hour of power is somewhere between 197 and 234. Maybe split the difference and ride with that?


Each test will and does give a different result. The function of the 4DP test is to check your FTP effort over an hour long test. I’ve done three, eight, and 20 minute tests as well as functional ramp tests. All give different results based on your ability to complete them. I’m a short effort rider and the three minute test is just about at my limit. So, every time, I get VO2 weakness and the need to ride long efforts.

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Hey @Eden_Masami and welcome to the forums. As others have said the Full Frontal 4DP test is exceptionally difficult to pace just right. There’s a great article on how you should feel and how to pace it here and it’s very much worth reading.

You could take FF again after you’ve rested and reset and aim for the numbers from the Zwift ramp. I’m suspecting you may have held back a little during the 20 minute portion of the full frontal test.

There’s a few vids that are a great test of the accuracy of your FTP. Vids like Defender or Hell Hath No Fury or Extra Shot or Long Scream. You could try any of those at either setting, see how you make out and adjust up/down from there.

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Thank you all you are so kind and I appreciate your help!

Ill take what you wrote in mind .

Few more things though that might help you assist me .

I did a half Monty test which I finished successfully, meaning there was no ramp I couldn’t do. I got an ftp of 191. That was around the middle of my training program.

Second, the 4dp test was, truly harder to finish than the ramp test. Maybe because of the longer duration time of the 4dp. When I got to the ftp section at the test I was totally blown by the 5 minutes effort so it might affected the results.

Thank you all one more time

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Watts per kg?? he may be 90kg’s and you 60kg’s, out on the road will be the true determination


To add to the excellent comments above (and, also, welcome!), 2 points on what you say here:

  1. Like other ramp tests, Half Monty is a ‘to failure’ test, so if you finished the ramp it’s actually a fail not a pass. It needs to see how far you can get, so completing the ramp doesn’t give that. The way you account for this is to start the ramp at a higher level - but not too high as you need to be riding for at least 5 (I think 5?) steps. I usually die (and I mean die) at ramp #10 or 11.

  2. the FTP section in 4DP is a little different to others (as people have noted). It is good that the 5 minute VO2 section put you on your knees. This is by design. If you hold back in this section then sure your 20min power is better, but the resultant power profile is not what it is intended to be.

Similarly the 1min effort at the end is not designed to be your 1minute max - it is designed to be your 1minute-max-after -all-the-other-efforts-and-a-known-recovery-time. The 4dp profile and resultant workout targets have this in mind - in particularly it accounts for how you have recovered after the 20 min section. It’s one big eco system and your results in Full Frontal mean nothing to the outside world. They dont even mean anything if you compare to another rider.

Hell, they don’t mean much if you compare to even yourself unless you know that you absolutely nailed every interval perfect in both cases and that there were no external factors.

It takes a few efforts to get the 4dp test just right, but in any sense it’s a measure of where you are now and for me the biggest benefit of Wahoo is the well constructed workouts built from your profile. You can always tweak, or retest.

And remember one final thing - Full Front is brutal, really brutal, if you do it ‘right’. It scares a lot of people - there are long threads on exactly this. They are worth perusing, but know that you’re not alone, it makes you stronger, and we all love the pain really!


If you finished the ramp in Half Monty the test is invalid. you’ll need to to do it again, the next time you do it the app will make the ramps harder so that you can’t complete it.


That will affect the results, sounds like you went out a bit too hard at the start and probably put out some decent watts at first but this is an average over the 20 minutes so once start to tire out that average will drop rapidly so that’s why pacing is so important. Say you did 250 watts for those 5 mins and then dropped to 150 for the next 15 mins, your FTP would be 175.


This is perfectly explained! :+1:


I always advocate testing by doing the 7 day test plan that includes the HM on day three which sets targets in the FF on day 7. This give a structured lead up to the FF, and having the HM set the targets, particularly for the 20min test, is very helpful. I try to just beat the target, and it’s killer. It’s a solid week of workouts too.

This is particularly helpful if you’re new the FF test to get the timing/pacing down. Once it becomes old hat, you may choose to forego the 7 day plan. Myself, I still do the 7 day plan as I think it gives the most reliable/reproducible results.


Hey @Eden_Masami ,
All the comments and advice given are spot on. Let us know how you’re coming along. Happy training!



Thank you guys I learned a lot so far.
I see the correlation now between the half Monty and the 4dp test setting the goal for the 20 minutes section.

By finishing the half Monty without having to stop I guess I could have push more which probably led me for a lower goal at the following 4dp test .

Allow me to add please, when I’m riding 60k races out side I usually make NP of 215w which is higher than my 197ftp. So if I can sustain a higher watts for loner time (2h instead of 1) what does it say about my actual ftp ?


It’s really back to what one means by ‘FTP’. There are several other threads where the argument around what ‘FTP’ means gets quite heated. For me, everything is an approximation of something that is not directly measurable unless you absolutely, ABSOLUTELY, nail the test (it’s a physiological concept that isn’t directly measurable, you can simply just try and push yourself towards it). And as above it generally doesn’t mean much outside the relevant testing/training environment.

If you can push 215w for 2hrs then of course your max 1hr power is > 195. But the indoors versus outdoors effect is significant, the testing protocol is significant, whether you just smashed a 5mins VO2 test is significant. Personally I don’t try and extrapolate from my FF results to anything outside of the Sufferfest. Even more so I know that if I have fatigue in my legs then a session even perfectly set according to my 4DP profile will not feel like it should. I’ll dial it down, and experience with the system (Systm…) helps with that - it’s still a bit of an art form but you get to know your body over time.

I absolutely get, however, that being able to translate testing results from indoors to outdoors (for instance) would be useful. Recently my outdoor power meter seemed to get out of whack (needed a recalibration). For a few weeks it was showing me pushing power up to 100w higher than I probably was in reality. I felt like Superman for a fortnight. A retest on the Kickr brought me back down to earth. Or, perhaps it didn’t because indoors ain’t outdoors?!

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When you do Half Monty again, make sure your MAP is set high enough (look in More=>Profile=>Athlete Profile ). A good sensibility test is that it should be about 20-30% higher than what you think your FTP is. HM calculates the ramp intervals, start and end points based on MAP. It doesn’t have to be perfect, just in the right ballpark.


Hey @Eden_Masami ,
Listen to this podcast:
Also check out other podcasts and especially the lastest ones on the 4DP metrics. You’ll get a lot of education/insight from our sport science team.



They way I look at it is it’s the result of a test, not a measurement of something fundamental or an underlying truth. First was doing a maximal 1 hr effort, which defined FTP. That’s kind of daunting, so other test were developed that had different less daunting intensity profiles and durations that were adjusted so the result of the test was similar to the results of the 1hr test for most individuals. SYSTM has their tests, from which they define/divine some other metrics they deem to be of value in establishing a baseline of performance against which to design training plans and quantify results.


Do you use the same power meter indoors and outdoors and if not do you know if they’re both accurate. Did you calibrate them both recently before the rides you’re comparing (if they are designed to need calibrating)?

well everyone here has said such good and wonderful things and all I want to add in is that my hardest sections are MAP and lately AC. which is funny because I went from Attacker to Sprinter. I guess I really got that sprint mechanic down finally. Map is just the hardest one to pace for myself because its always a choice between do I want to grind or spin and the answer is you have to do a little of both and I think you have to grind till you break free then you spin your little heart out for as long as you can hold out or 5 minutes. FTP is a just a brutal slog fest to be honest and every time you look at the clock its like time gets added. Best thing here is to pretend like your climbing and lock in that form and don’t stop till you crest and you’ll know cuz it gets real easy. Last but very much not the least is AC this actually isn’t just about your anaerobic capacity at all that was already algorithmic out back during your MAP portion. This is all about punishment and how well you can function when all you got left for energy is fats. simply put this is about how well your system recovers. Then your done and you should feel no better than a wet dish rag. And that is what makes 4dp so magically different than some of these other platforms because it is an entire full body experience all in one shot.