Half Vs. Full FTP

What can account for such a difference in the FTP results on these two test?
Is Half usually higher than Full for some reason?

I did the half just a few weeks ago and the full today. It came down 15 points from that half test.

I’ve been in a low volume plan so maybe the lack of hours but it still seems like a lot for just a few weeks.

For reference, the last time i did the full (12 months ago), all of my metrics went up compared to that last full test.

Probably any number of things. All of these tests, although we call them “FTP tests” they’re not really testing your FTP exactly. They’re testing your performance during the protocol, but from that, they’re estimating your ftp because FTP is difficult to directly observe and what underlies it is multifaceted and kinda squishy.

Coggan’s definition from Training and Racing with a Power Meter was the max you can sustain in a quasi-steady state, and even his sixty minute gold standard, he didn’t say that IS yoru FTP, he said it “best approximates.” I’ve heard another definition from a knowledgeable source that was the max power you can sustain using almost entirely aerobic energy production.

So both tests are useful to judge your progress, but both are estimates and may or may not actually be your FTP. You can train on them but you’ll also need to use your judgment and potentially adjust as needed to get the right workout.

But to your specific question as to why these mgiht be different: traditionally performance on a ramp test is a decent proxy for VO2max (as is a five min test), and then you adjust the result you achieve by a multiplier to get FTP. But as you can imagine, this is kinda like 220-age for heart rate, for sure it is accurate at a population level, but for individual athletes it can be way off. In particular, FTP is not a fixed proportion of Vo2max: just ask a pursuiter on the track vs. a GC contender, their ratios are gonna be wayyyyy different. And so, athletes with a high anaerobic capacity and/or VO2mx relative to FTP tend to get FTP overestimated by ramp tests because they need a different multipler (smaller).

So, the Half Monty protocol with the constrained HR section is intended to help address this but it’s probably not going to be perfect (because nothing can be perfect, you always have to account for a squish factor because our tools are much more precise than what they’re measuring). THerefore my guess would be, are you a person who has a higher than average 5 minute power compared to FTP?


Thanks for all of that. Makes sense.

You are correct that my MAP is higher compared to my FTP!!!

I guess I just thought that even though these are different test that there wouldnt be such a difference. I wondered about volume since when I did half back in November at the end of my racing season (when my volume had been huge multiple months) my FTP was waaaayyyyyy higher.

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There are a yak ton of posts on this topic. Here is a something from Sir @Coach.Mac.C on the topic for you to consider.


Yup. Also 15 watts might not even be that much, esp if you take into account other factors like pacing, freshness, etc


Thanks Glen. I had noticed that when I started this thread and read a few of them but hadn’t seen this response. It makes total sense.

BTW - when i got my half score back in noemeber and my workouts for the next while were based on that number, i was barely getting through them. I noticed it and wondered about it but attributed it to my drop to a low volume program. I “powered” through until the next half but really should have lowered the setting before that.


I’m very fortunate that for me, HM is very predictive of FF. Always within a handful of watts.

@curdog16 I was disappointed the first time I did Half Monty and then Full Frontal a few days later. I had similar drop in FTP on FF compared to HM.
I’d used my Garmin Edge 830 auto-detect FTP findings for a long time, and was then running about 192W, based on Garmin numbers when I followed some of the weekly prep plan for HM and FF at the end of the week, back in November '22. I was pretty fresh for both tests, and felt good about the HM results that said I was at 211W.
Throughout much of 2022, I was usually in the 215W range, +/-5W, based on my Garmin detection numbers when I made honest hard efforts of at least 20minutes at high output outdoors (the majority of my riding is outdoors and not following any plans.)

But I lost significant power when I had pleurisy and immediately got pneumonia in early-mid September 2022. I lost time on the bike for a couple weeks, got back on it soon and slowly increased distance and elevation, but was weaker, and even after getting back to good volume miles and solid work, my numbers remained well below 200W, mostly close to 190W whenever the Edge 830 gave me results. (Got results from my Fenix 6S also, but these are ALWAYS about 12-15W lower than the Edge and in my mind, clearly wrong, but that’s another baffling story.)
I couldn’t understand why I wasn’t gaining again, especially when being more disciplined about getting rest days, and increasing rides done at a disciplined Zone2 because I had ALWAYS spent much more time than I should at zones 3 and 4 and 5, and I was finally realizing it was causing me to lose any real chance at making gains. (This was true even BEFORE I ever got sick, and now more important because I’d lost about 10-15% of my power numbers, and my age (65) wasn’t a sufficient explanation for that much drop in a short time, when I was still riding as much as ever and doing things as I’d always done. (Except I actually started valuing rest and reduced intensity rides, (AND very recently, have actually started using SYSTM to work on 4DP numbers in a more purposeful way than I ever did before. And it IS paying off, I think.)

So back to the WHY of the discrepancy between HM and FF results for FTP, I read the replies to your question and it certainly adds up to what I experienced. My first HM results were high on FTP compared to my Garmin Edge. I thought that was GOOD!
Then I got slammed by the FF results. I lost 15W on FTP and 30W on MAP, though my AC went up 13W and NM jumped 109W. My rider type was an Attacker.
In light of what was said by @devolikewhoa and also referenced by @Glen.Coutts to what was said by @Coach.Mac.C my lowered FF results make sense. As an Attacker, the HM ramp test provides “artificially higher Sustained power values (FTP/MAP).”

Since November, I had Covid in early December, lost a little more riding time but mostly it was a nuisance only. But I still wasn’t making any real progress with FTP numbers as time went on. I did more time indoors than usual, even for me in “wintertime,” which for us here in the mountains of Virginia, USA, this year was very mild after December. I did more intervals work, and I tried to choose workouts in SYSTM that were specifically geared to FTP and MAP, and for a few weeks recently, I also targeted AC and NM because I knew I really didn’t do enough work on sprints and efforts below 2 minutes.
Workouts were fun, I enjoyed the extremely demanding intervals, and felt they were helping me make gains.

So last week, I had a lighter than average week in terms of miles and time, but it included on Sunday the On Location “Galicia: Camarinas to Muxia” ride, followed by an Earth Cycle easy ride to recover and cool down, then a long travel day Monday, then “Micro Intervals: 3 Sets 8 x 20s” Tuesday, in which I increased the difficulty by 5% on second set and 10% third set of intervals, and was able to hit the targets. I was feeling stronger overall for the first stretch in more than 6 months.
Did nothing Wednesday except chores at home, and Thursday, I took a heavy climbing day on the mountain bike, doing an out and back long ridgetop ride of Fore Mtn with a steep climb at one end, steep and technical descent at the other end, steep climb back up and steep descent to the starting point again, 23 miles and 4000’ of climbing. A fabulous but taxing ride!
Friday, I did chores at home, was feeling some pain in my rear thigh above the knee and thought it was soreness from the mountain biking, but found a deeply embedded black legged tick was the cause. Couldn’t even see it but my wife did when I was rubbing my leg and complaining that I shouldn’t be sore from that ride… We both worked on it and got it out, but there was a red swollen area more than 2" diameter, and it was pretty warm to touch. Fore Mtn is notorious for ticks, even in winter, so I either picked it up the day before, or else the previous Saturday when I was running a 26# backpack leaf blower on that same trail, hiking 6-1/2 miles. I sure hope it hadn’t been there that long without me discovering it, but it was small and I couldn’t see it without a struggle.
I took 200mg doxycycline Saturday after reading up on treatment for an infected tick bite, and things began to improve quickly, swelling going down, itch going UP! Crazy itchy, but the pain was reduced sharply by the next day, and it has continued better every day.

So also on Saturday, after taking the antibiotic, I was planning to ride a long ride outdoors but on spur of the moment, I decided to do FULL FRONTAL 4DP test again. I’d reached Peaking status according to my Garmin devices, training load was down a little, and though the Fore Mtn climbing of 2 days prior was not insignificant, I figured I’d give it a shot.

I maybe managed my effort a little better than the first time, and had less major fade on the 20min effort than before, when I barely hung on. Didn’t have as much left to hit the 1minute final effort quite as hard at first, but maybe held on better? Still lost ground, but I think that was as much mental as anything; I really didn’t care to force things as much at that point as I did last time.
Now SYSTM says I’m a “Rouleur” instead of “Attacker.” FTP came up to 212W from 196W, though my Garmin had already been down to 193W (and lower) for awhile. I just didn’t lower it in SYSTM app.
(I did run the Edge simultaneously with the FF test and it did also come up, only to 205W FTP, but that also makes some sense because it is still just using a 20minute effort and reducing it by a percentage, not giving account to the other hard efforts done in FF before that 20 minute push, as SYSTM does.)
My MAP also increased from 233W to 249W.
My AC dropped to 336W from 356W, and NM dropped to 727W from 785W.

Overall, I think the results of my tests have been pretty accurate to what my body has been telling me. I’m especially happy to see some improvement finally showing because it’s been a puzzling thing that I have lost as much power as I was seeing on the Garmin results, and couldn’t understand why I wasn’t gaining it back by now. It’s been very slow for sure, but it’s FINALLY starting to come back.
(This is a screen snippet of the 3 tests.)

Quite amazing how close your latest 4DP test figures are to my last one, embarrassingly July last year! must psych myself up to do another one soon? I am 69 and weigh 61kg’s

@ozmadman I agree, those numbers are close to identical for all practical purposes! I’m 4 years younger and about 6kg heavier, so you’re keeping your strength really well! I do next to nothing in terms of strength workouts, just Foundation Training Original 12mins w Dr Eric Goodman and 6pack Abs 8pt Plank Challenge YouTube videos a few times a week. (And my back tells me I NEED to do them daily, so I’m trying to get disciplined about that.:roll_eyes:)

I’ll tell you what surprised me is that the Full Frontal did not drain me as much as I figured it would. Not that it wasn’t very taxing during the workout because it was…
But the very next day, on a whim, I decided to do a fairly big ride. 71 miles with over 4700’ of climbing (pretty typical percentage for this area), and moderate winds to push against most of the ride. I endured well, averaged 16.7mph, not counting stops of 15 minutes total, taking pics and refilling water bottles. That was my best time on that big loop by about 13 minutes since before I got sick last Fall. I was elated to maintain that speed; I’d have expected something more than 1mph slower with the number of climbs on that loop.
My conclusion from that is that the FF does not necessarily take as much out of me as the psychological weight it may carry. I resisted the temptation to add some recovery miles right after doing the FF, and I think that was a good choice. (I tend to want to get more miles than that on ANY given day, which feeds my tendency to overdo and stay beaten down, a habit I’m trying to “PUT TO REST!”
I did only PARTLY follow the Prep Plan for HM and FF the first time round in November, missing a few of the days altogether, so I was somewhat rested compared to my often-overtrained state. This past Saturday, doing FF on a whim with no HM before and no prep week, I think it worked well and gave usable results, so I now think I can judge when I’m ready based on when I’ve had a lighter than average week, and have had a good mix of 4DP focus in recent weeks leading up to it. That plus my Garmin training status actually having GOOD things to say, like PRODUCTIVE status for a solid 4 weeks prior, which is a radical change from what it’s been telling me all fall and winter!
It’s been Unproductive, Overreaching, Detraining, or Maintaining for most of the time since early September. Finally got into a Productive groove in late February and stayed right there except for the bump to Peaking last Saturday, when I happened to decide to do FF. :smiley:

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