The picture painted by your report on how you feel post-ride and the metrics don’t make sense to me.
I would guess either your an extreme NP buster (though I haven’t seen those for 4+ hr durations, more like 1ish hr.) Or your FTP estimate is low due to differences between indoor/outdoor power measuirng devices or cooling / other indoor performance limiters.
I think maybe a combination of both?
Rather than the 20 minute test, I would suggest doing one the progressions from Emperical cycling:
Since your FTP number is likely low (and almost certainly not high), trying one of the longer progressions with your current FTP will tell you if it is low. Note that in this case the tests won’t actually give you a valid FTP because you started at a very low number, but at least you will get a good idea that it is low.
When I switched to a Kickr bike, my ftp dropped almost 30 watts compared to what I was getting from my left crank arm power meter on my bike.
I know you said they’re within 1% but I suspect you’re comparing apples to oranges. It would make sense if your FTP is being measured inside a decent amount lower and then outside you’re getting a handicap from that crank. I had the same discrepancy with both stages AND 4iiii.
I finally got some power pedals that are really close to the Kickr bike, so now my indoor and outdoor rides are in sync.
Or you’re just THAT awesome. 
Have you actually tried the ramp test at one point?
Exactly, FTP might not matter to you as a metric, but it is essential if you want to be able to train properly. If your FTP is off by a massive amount (which seems plausible in your case), then a supposed threshold effort is, physiologically speaking, just tempo. And VO2max might be threshold or even sweet spot.
No, quite the contrary: that is usually recommended. However, if both of your power meters differ by that much, you should first figure out which is producing bad numbers (perhaps both). E. g. you might have a leg imbalance, and your single-sided 4iiii could then over- or underestimate power.
E. g. I have trained with a single-sided 4iiii power meter for several years. But my body is smart-lazy: I developed a severe leg imbalance which overemphasized the left leg (55:45 under normal conditions, but it could reach 58:42 in recovery valleys when I was exhausted). That is because to raise the indicated power by 2 W, I only need to raise my actual power by 1 W on my left leg. If that is the case, then your 4iiii power meter might measure correct numbers, just the assumption that your legs contribute equally is false.
Many trainers offer left/right leg imbalance measurements. These are not as good as power meters with truly independent measurement of left and right power, but they can give you an indication.
Also, what are the absolute power numbers you are producing? 20 W at 250 W? 20W at 300 W?
I don’t think that is a good idea, especially if @OzCanuck doesn’t actually have an idea of what his actual FTP is. Like you wrote, Kolie Moore’s test protocol might give you invalid results if your initial guess isn’t in the ballpark.
IMHO he should keep it simple, focus on one simple test and then validate the number he gets. I think a lot of overcomplication and overthinking when it comes to FTP test protocols can be completely avoided if you simply verify your numbers and get a good idea how close your actual lactate threshold is to the number a particular test spits out.
If you have no idea where your FTP sits, I think a ramp test is the easiest option. Also with the 20-minute test, you have to guess your FTP first.
@DwayneB You raise a very interesting point and suspect that has something to do with it. I think I have retrained some of my old ice hockey attributes where I would go all out for a minute or two and rest for a minute or two. But then if the FTP isn’t set quite right the long sustained efforts on the trainer it would also make it easier to repeat efforts too?
And holy hell, your outdoor power is smooth, especially on your sweet spot ride! It would seem that I need to get better at consistent outdoor power pacing. Something I am working on in the sections of my weekend rides that are flatter and perhaps easier to try to dial in a tighter power range.
@Craig_G could you explain more why the picture I painted doesn’t make sense to you, keen to learn more.
@toyman, appreciate the tip on Kolie’s protocol. I hadn’t heard of that one. Also appreciate your perspective on what you think is going on. Sounds like there is more or less a consensus starting to form.
@SexyCoolguy (great handle BTW) Pretty sure I am not that awesome especially given I am only 18months into this serious training. I think it’s something worthwhile trying to fix because if my structured training isn’t based on the right FTP it might be why I more or less plateaued after 5 months of structured training despite all the smarts built into TrainerRoad.
Maybe the solution is to spend more money on pedals. This is cycling, of course that’s the solution! 
Have you actually tried the ramp test at one point?
@OreoCookie Yes I probably got in several between June of last year and January of this year before AI FTP hit the platform. All of them were performed on the Kickr.
That’s a fascinating tale around your left/right balance. I wonder if my physiology is that smart. I think I have seen DC rainmaker has a power comparison tool that I should try to see if it’s available and give it a try. The key challenge is trying to figure out what device is giving the most accurate number (I am assuming the kickr) but maybe that’s not as important as working with a consistent number both indoors and out.
Also, what are the absolute power numbers you are producing? 20 W at 250 W? 20W at 300 W?
Not certain I understand your question, can you extrapolate?
What was your FTP then and what it is now. If numbers indoors and outdoors differ, please give us both. You only gave power differences.
What was your experience with them? Did you feel the powers were accurate? Or did you notice they were systematically too low or too high?
A little FTP history. I have been using TR since June 20th 2021 essentially when I picked up a kickr, I had been using the 4iiii since April 2021 so had a bit of outside power experience. Hopefully I get to answering your question.
I didn’t take a ramp test to start, instead I used the FTP estimate I was getting from using Garmin and absolutely failed my first threshold over and under session. (Ritter, threshold 3.7) I simply could turn the pedals anymore after 45mins
Did my first ramp test and it pegged me at 260w in July 1 2021. I did ramp tests about every 5 weeks, gradually progressing to about 280 to 285W pretty much from November 21 until now, with recent AIFTP clocking in at 288 (July 3rd, all time high)
Until the race in May this year my outside ethos was go as hard as I can all the time. Weather permitting this was usually a 2hr ride Saturday, and a 3hr ride Sunday with occasionally longer rides up to 4hrs on the Sunday. IF was always above 0.86 and looking back I see a couple of the two hr rides had an IF of over 1. Which I suspect means the FTP is out. In addition during this time I was doing various sweet spot base and build plans in LV during the week and very rarely couldn’t do a workout and as such met the progression of adaptive training. From time to time I might have a bit of what I call a cadence crash on a 1.5hr threshold but even that became rarer as I worked out fueling and cooling.
Since the race I have been focusing on keeping weekend rides in Z2 and if I can get in longer stuff over 4hrs while also trying to manage progressive overload through a training block. This has made accomplishing the structured training even easier and I haven’t failed a session since switching.
I found ramp tests to be an odd experience if I am honest. I usually did them on a Monday at the start of a new block and possibly was carrying fatigue from the usual weekend rides before. I did find it interesting that there was a point in them where I couldn’t possible turn the pedals any more if my life depended on it. But that usually happened well before I was out of breath. I
I now have some longer outdoor and indoor rides where I am keeping power in Z2 and also keeping an eye on heart rate. I’ll have to check but my guess is that outside I can hold about 20w higher maintaining the same relative heart rate which goes back to what everyone is saying here is that my FTP on the wahoo is out by about that much.
I guess the solution here is to use power match and see what happens, could be interesting especially with AI FTP.
And if I understand correctly, you are relatively new to riding, correct? If that is the case, maybe you don’t have a lot of experience going all out. That’s why I am not sure a 20-minute FTP test would be a better fit: you might start way too conservative, nowhere near your limit.
That means you likely stopped too early. This is common with inexperienced athletes: you feel like you are at your limit even though you aren’t anywhere near it.
The point of this test is to get to the point of maximal aerobic uptake, which then determines your maximum aerobic power (MAP). At the end of a ramp test, you should be panting and be out of breath.
That’s also what you should feel when you fail VO2max workouts. At the very least your breathing should change. Getting to know how different power zones feel and how your body reacts is an integral part of training.
I’d forgo AI FTP for the moment and try to push yourself further with ramp tests. Also make sure you are well-rested before a ramp test. Moreover, try resistance mode rather than erg mode. Personally, I don’t like erg mode, because it works against my muscle memory: I have had a dumb trainer before and rode outdoors for decades. In erg mode when you are at the limit — or think what your limit is — you could enter the grind of death: you are below the power target and the trainer cranks up the resistance. Since it is harder and you are struggling to meet the power targets, your cadence will slow and the trainer cranks up resistance even more.
Keep it simple. I would not introduce too many different variables at the same time, you will never know which is which. From what you tell, there are likely several factors and you should address all of them in turn.
Thank you very much @OreoCookie for providing your wisdom on the subject. Yes I am relatively new to this type of training. I am not new to riding bikes but definitely in the early phase of structured training to try to get faster.
Even in the last year or so I am learning more and more as you say by feel, looking at numbers and figuring out what they mean for me and how to structure things differently. At first it was to see just how much I could improve and now trying the racing hat on as a way of putting the hard work to use.
I did go and use @dcrainmaker analysis tool to see what’s going on with power meters, definitely a bit more of a difference when you get into the detail, if I have done it correctly you should be able to see the difference here DC Rainmaker Analyzer
Don’t get carried away at this point.
I think getting to know the actual sensations of what the different power zones feels like is essential. Training with power meters makes that so much easier since you don’t just have to go by feel, but you can connect feelings with numbers and learn much, much more quickly.
Maybe i missed it, but I dont think anyone has mentioned it yet.
Potentially you have an equipment failure?
The reason I say this is I had some way higher power numbers from some garmin pedals a few times and I had to remove those rides because it was almost impossible, like 15% higher in every area. If everything else is straight with you maybe thats it?
Sure, I’ve found with a properly set FTP my experience roughly aligns with this chart:
Blockquote
- <100 TSS = Low (Easily recovered by the following day)
- 100-200 TSS = Medium (Some residual fatigue present the following day, gone by 2nd day)
- 200-300 TSS = High (Residual fatigue usually present after 2 days)
- 300-400 TSS = Very High (Residual fatigue lasting 2-4 days likely)
- 400+ TSS = Epic (Residual fatigue requires 5 days to dissipate)
My experience varies a little based on IF of the ride, so a 150TSS ride with high IF might bump me more into the High fatigue state with 2 days of recovery needed, but in general this chart has matched up with my experiences. If people are regularly doing back to back 300+ TSS rides and feeling ok or doing 400TSS rides and feeling ok it makes me question whether the FTP protocol being used is a good match for the individual, whether test environment is compromised (cooling, etc.) or something else is going on.
Here’s the page I found the table from. I had seen something similar way back in the day when I first started training with power in 2007 or 2008:
https://tailwind-coaching.com/2016/04/13/training-stress-score-fatigue/
Yeah, agreed, the chart aligns roughly with my experience as well. I did two harder rides last week (286 TSS and 234 TSS), and I could definitely feel the fatigue for two, three days. To put it in perspective, the 286 TSS day was a 7-hour ride (5:46 hours moving time) at an IF of 0.70 with 2.900 m of climbing; I expended about 4.000 kCal. I could have gone a bit harder, but not by a lot. A 400+ TSS ride would have to be an all-day ride with tons of climbing.
@varmstrong no, you didn’t miss that. Definitely something to consider, in the analysis of the one instance where I had double files there definitely seems to be something going on with the 4iiii once power gets over 300w at least according to DC rainmakers analysis tool. Thanks for raising it, I’ll keep an eye on it.
@Craig_G, that’s a super helpful chart and I’ll have a look at the tailwind coaching link more closely this evening.
@OreoCookie appreciate your perspective on the chart as well.
A question for you both, how would you describe the feeling of carrying fatigue into the next day or even two days later?
When I was really pushing hard on both outside rides on weekends (IF about .86) I could usually complete the training block but definitely felt like I was on a knives edge in terms of sleep and work stress and its more manageable now that I have clocked weekend rides back. Certainly the more you get into this type of training the more you learn about yourself and what affects and how you can handle fatigue.
I really appreciate the time you are giving me here especially as I am pretty new to all of this.
One of the signs is tingly legs. But the main symptom is a generalized fatigue, the feeling where you just want to sit down and chill or sleep.
That is really important: rest is a crucial part of training. This is something I had had to learn, and I think it is the most important lesson. You cannot cheat yourself: if you do not rest enough, it will come back to bite you. So if you do a hard ride that you know requires two days of rest, you cannot just “push through”, you need to respect your physical limitations and act accordingly.
For most of us, sleep is a huge one, and you need to be smart here: if you haven’t slept enough for some reason or there is a marked increase in life stress, you need to adjust your training accordingly.
Before I started structured training, my idea of the best way of getting faster is simply “riding fast”. If I didn’t feel fatigue in my legs, I wasn’t satisfied. Rest days were an annoyance. Now I appreciate them much more. Ditto for endurance days: these are easy days with a purpose, and they are a good contrast to the hard days. Moreover, you don’t want to be on the knife’s edge all the time. It may feel like you are leaving something on the table, and if all you look at is a single workout, you do. But looking at it across a season, you probably aren’t.
There are layers of fatigue. The one that hardest to manage is the one that spans across a season, the one that builds because you’ve been doing workouts for many weeks in a row. It is hard to manage, because initially you feel nothing. But later in the season it can really cut down your error margin to a tiny sliver.
Overall, my advice is to keep things simple and slowly start building good habits bit-by-bit. Start building good training habits, good sleep habits, work on your nutrition. Just don’t do it all at the same time and to a degree that constantly puts you on edge. Start with a low-volume plan and pad that if you must. Or just add an outdoor ride on the weekend.