Having trouble/inconsistent performance with threshold workouts

I’ve been having a good year - weight is down and FTP is up! I got my highest AI FTP detection result yet 2 weeks ago @ 339W. That week I did 3x20 sweetspot @ 90% (306W) and it rated it “moderate”. My last big event of the year is a fondo on 10/8 that’s 101 mi and 8k ft of climbing, so I figured it might be a good time to try to work on TTE with my newly-minted FTP :rofl:

I know some people use Lamarck (4x10 @ 100%) as a guage to see if their FTP is close, but I ended up doing 5x10 @ 100% (340W) last Tuesday over lunch and had plenty left in my legs for 90 mins of endurance after work. Thursday I tried 2x20, but had to turn down the second interval to 96%. Today I had 3x16 @ 98% scheduled and bailed halfway through the second interval. I could barely keep my cadence over 80 and my legs were done. HR never got above 162 BPM which is roughly my LT HR per Intervals.icu, Garmin estimates, and from past 20 min FTP tests.

At this point, I’m not sure if my FTP is overstated (likely based on the consensus in most FTP-related threads :smiley:), I’m just fatigued (last rest week was 4 weeks ago), or if something else is going on. There haven’t been any big changes in sleep or nutrition over the past few weeks if that helps. Intervals.icu has my FTP at 325W (I think based on last week’s 2x20) and my last Garmin estimate was 343W maybe 2 weeks ago :grimacing: Recent power PR’s are noted below.

5 min 374 W
10 min 341 W
20 min 340 W
30 min 318 W
40 min 320 W
50 min 311 W
60 min 312 W

In my shoes, what would you do? My event is in 5 weeks then I’ll probably take a break or a few easy weeks before getting into fall base training mode. A few options I’ve been thinking about:

  • Lower threshold to ~325W and work on longer SS intervals
  • Lower threshold to ~325W and try a threshold progression again
  • Take an easy week and try a Kolie Moore test next week


More is not always better.

In college I felt great after a long run and came back later that day and did a double. I was flat all the following week. Could be a lot of factors, but the take away was that doing more when you are feeling good is not always the best thing to do. The “extra” comes at a cost that you pay back later.

To me 5 x 10 min @ 100 FTP + 90 min of endurance is one heck of an effort. You might just need a few extra days recovery…


One thing is that it sounds like your week ago 5x10-min @ 340W / 100% was fresh. Unless you do a lot of threshold work, it can carry a high recovery cost (compared to tempo / sweet spot). So I’d start with that and ask myself why it made sense doing a 2x20 just two days later. And IMHO any longer intervals from 96-104% count as a threshold effort. I wouldn’t get fixated on dialing down from 100% to 96%.

For another perspective I’d look at PMC and see how fresh I was today. And if both a week ago and today had similar rest/recovery.

I’m not inclined to change ftp often. My 10-min threshold efforts usually have the same HR response, so I’d use that information to evaluate the 5x10 effort. If it looked legit compared to other 10-50 minute efforts, I’d leave ftp as-is and continue training until there was some other evidence (fresh efforts) that ftp has changed.

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Dude - congrats on your FTP bump. Based on what your wrote I think you probably due for a recovery week - you are possibly overreaching and may get yourself in overtraining territory. If I were in your shoes I’d take a rest week with some active recovery and then duplicate your 4x10/5x10 next week and see how it goes. Going from 4x10 to 2x20 was a big jump. At this point I’d think you’d be good to not over do it and just maintain what you’ve built up. Good luck.


I’ve done alot of sweetspot this year and I think it really helped my fatigue resistance that was sorely lacking in prior years. I haven’t done much sustained threshold work this year though.

Tu/Th have typically been my interval days. 5x10 @ 100% was hard but manageable so I thought I’d be good to go on Thurs. Folks talk about 2x20 being very doable if your FTP is accurate, so I wanted to give it a shot. Figured it was less time in zone too so it should be easier :thinking: It was not! Sounds like I misjudged the amount of fatigue following threshold efforts!

I appreciate the input @WindWarrior

@Stevie_Dee @Jolyzara Thanks for the tips! I think I’m going to take an easy week and then think where to go from here.


I wonder if instead of doing another threshold workout if a VO2 workout (shorter reps but higher intensity) would have felt differently? For me… sometimes shorter reps, even with higher intensity can be more manageable for whatever reason.

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If the best you’ve done for 50+ min is ~310 W, what makes you think that your FTP is 325 W, much less 340 W?

3 full weeks of training, right? More or less? Anything big you do now has a high level of self-sabotage risk, and a low likelihood of moving the needle on your fitness.

I’d be tempted to change very little, make any intensity above tempo race-specific, and prioritise loafing, eating and sleeping.


3 reasons for the ~325w number…

  1. Because I did 318W for 44 mins on an outdoor ride where I was fresh and felt I had plenty in the tank. When I’d finished I felt like I could have done more.

  2. 95% of best 20 min recent effort. This isn’t gospel of course.

  3. Absolute faith in our AI training overlords

Thought 2 AI overlords (TR and Garmin) have you around 340? From that longer 44-min @ 318 (average, right?) ride it sounds like either it is an older ride and fitness bump since then, or you were not really pushing it. :man_shrugging:

FWIW my belief system for FTP is a) be conservative, b) it doesn’t change often, and c) base it on longer 20-60 minute efforts.


I think that’s the approach I’ll take going forward. I got sick a few times last fall/early spring so my fitness was in the tank when I started really training for this season. I think that almost bumped me back into some noob gains territory :rofl: and the AI FTP detection seemed to track with how I felt on endurance/tempo/SS rides. I haven’t really done a proper FTP block though. I’m learning now the longer format test is likely the way to go.


I think this to some degree :point_up_2: It was a day where the stars aligned…nice weather, some free time, pancakes for breakfast :smiley:. I didn’t set out to do an FTP test, just felt like riding fast and had a good day.

First of all, FTP is functional threshold power, not the best power you have done, especially for training it’s something you can repeat during the week with some regularity, and clearly, 340 is not this power for you. I know the feeling you are talking about - the feeling you are flying and have unlimited tank of energy. For example, I had done 3x15 with 335W. What was my FTP then? 315. I could never repeat this particular day in any way.

Second - there is no point in doing threshold workouts with 100% FTP as 100% is not 100% but oscillation between 95%-103%, as you never hold constant power. And you fatigue A LOT more crossing this line while doing 60 min TiZ. You will get the same results with 95%-97% but will recover a lot better.

Third - 10min is barely fatiguing when it comes to FTP. I am a huge proponent of threshold training and for me, 10min and 15 min are completely different when it comes to fatigue during intervals. 10 min I can do just over FTP (102-103%) and repeat this 4 times. 15 min I can’t.

And conclusion:
Do even 3x15 as a base. Start to learn how FTP feels, how you breathe and how hard it’s in terms of RPE. While doing 4x15 around 95-97% of your FTP basically the last 5-10min should be hard. Rest should be easily doable without any moment of doubt (of course if your cooling and nutrition are dialed in). For me my FTP is I would say starts with 6 for 8-10min, increases to 7/10 RPE, and changes to 8 at the end of intervals (9-10 is vo2 max feeling). So it’s work but not so hard.


This is the stuff I was hoping to figure out by doing an FTP block, especially since my FTP has changed a decent amount this year coming back from being sick last fall/spring. I’ve set a bunch of lifetime PR’s in the last month. Combined with pretty significant weight loss, my RPE is in need of some calibration.

I did 3x20 sweetspot @ 306W/306W/311W the week of my FTP bump. HR was constant and never touched my LTHR (as estimated by Garmin and intervals.icu @ 162 BPM). I kept raising the power in the last interval because it felt borderline easy and I could have done another interval if I had the time. 306W would be 90% of 340W or 95% of 322. The following Tuesday was when I got through the 5x10 @ 340W. This led me to believe my AI FTP detection result might be in the ball park.

I just wanted to add some more context! I appreciate the input for sure.

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If you feel it has changed it has probably changed. I just never estimate my ftp after single workout. 3 threshold workouts that feel similar is for me usually a sign that the change is permanent. Of course there are jumps that are hard to perceive or believe - for example after 3 months of no activity my FTP has jumped 30W after 2 weeks of training. I could never guess that but it’s repetable and I know how it feels. Sorry for talking about the feeling so much, and I am number guy, but for me it has become best tool when it comes to sst and threshold workouts.

Just try more workout and see how they feel. If you fail, you failt but some work is always done. KM test is the best for testing but still requires quite a lot of mental effort and at least some preparation when it comes to eating and shedding some fatigue (i have observed around 10-15min of TTE difference in myself without proper fueling off the bike).