Large fluctuations in day-by-day form

I am a 34 yr old male, been using TR for 2nd year. I am not on a training plan, just mixing indoor and outdoor rides trying to keep similar TSS each week around 350. My FTP should be around 260-270.

Recently I had problems completing TR workouts, had to reduce the intensity and then bail out completely. This happened to me twice now in last 2 weeks.

My FTP is set at 260 in TR, which should be a bit lower than actual FTP, because I did an outdoor ride with max 20 min power of 288 10 days ago (so substracting 5% from that is 273) .

Even with the conservative FTP I was unable to complete The workout is challenging but in normal conditions it should be perfectly doable for me.
The legs were dead after first 2 intervals, I had to reduce intensity by 5% and even after that I bailed out after 4th interval.

I am using Elite Direto, I have compared the power numbers with my power2max and they match pretty closely so this shouldnt be an issue.
I am also aware of differences between outdoor and indoor FTP, but in the past they were not much different, so determining FTP from my outdoor ride should be safe.

So I guess it just comes down to fluctuations in day-to-day form, but I didnt expect the fluctuations to be this big? I had a longer ride during weekend (3,5 hrs), which was a bit unusual and could cause bigger fatigue, but I had 2 days of recovery before the workout.
Comparing with my ‘real’ FTP of 273, i dont think I would be able to complete yesterdays workout with FTP set higher than 250, which is 10% lower

Do you guys have these kind of days where you have reduce the intensity by as much as 10%? Is it common?

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The short answer is no. However, I think your real question is more likely why you had trouble with Emerson.

You really haven’t provided much info about the specifics of your training that make up the weekly 350 TSS. However, I’m guessing there isn’t a lot of time in zone (TiZ) of sweet spot (88-94% of FTP) and threshold (94-99%) to build significant fatigue resistance (more likely your outdoor rides have a lot of active recovery and endurance). Emerson, the ride you provided a link to, is a really hard ride! - 5x10mins of over/unders. I think you should consider starting at SSB LV1 from the beginning. If you follow the normal progression, you’ll build the fatigue resistance you need to do Emerson.

Thanks for the reply. I have completed SSB LV1 in april/may this year, although it wasnt strictly by the plan because of time restrictions, but I have completed all the workouts in that plan.
But I think you have a valid point regarding time in SS/THR zones, since SSB LV1 my training was a bit of everything, some Vo2, some endurance workouts, little SS/THR, so I guess I have lost some of the fatigue tolerance.

I have a somewhat similar conclusion to yours that I should get back to SS workouts, since right now I find these threshold workouts very demanding both mentally and physically.

My feed back was based on my own TR experience . . . I entered TR one year ago this week. I had a fairly large base at entry (average weekly TSS was about 650-700 prior to joining TR). I thought I’d go straight to build and did something similar to you - tried an over/under workout . . . failed as you might imagine. So I went right to SSB MV1 (although I modified all of the workouts to provide me the volume I needed). And the results were great.

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Yep that makes total sense, I guess our cases are pretty similar except your weekly TSS is double of mine :smiley:
Thanks for helping mate


Have you had a recovery period recently? I don’t mean a couple of days recovery, I mean a couple of weeks of much reduced TSS? If you’ve been keeping the TSS pretty consistent for quite a while you might just need longer bit of recovery to really absorb all that training load, after which you will come back stronger.

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yep that could be also a contributor… its just really hard to take couple of weeks off during the summer :smiley: but perhaps I should just focus on outdoor rides for a week or two and not bother with TR and threshold etc.

If you can do this, can’t you use powermatch so you can be sure the measurement is consistent?

On the more general point, is your room cool enough and are you getting enough airflow on your body as you’re working at these high intensities?


I would not rule out the trainer itself, especially if you are using ERG mode. I have had many times whereby the trainer can sometimes make the pedal stroke seem different and this can sap the legs. It’s hard to quantify different, but it can happen.

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I’d do a ramp test. I’m in a very similar situation to you, held an average of 280w outside for 20mins giving me an ftp of 265w but a quick ramp test indoors had me pinned at 225w and the workouts feel about right. I think there’s a skill to riding a trainer as different muscles fatigue even though nothing changes with position at all. I’m relatively new to training but I fully believe there are huge differences between indoor and outdoor watts.

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I am not using powermatch because the numbers are consistent every time I check them :slight_smile: I am using BT for controlling the trainer, would have to use ANT since my p2m doesnt have BT.

But you have a point with the room temperature. I am aware of the negative impact of high room temperature, and even if I try to deal with it (open windows, big fan blowing at me), I realized that during these threshold intervals I feel a shortness of breath. Maybe the combination of temperature (~24-25 celsius) and humidity has a negative impact on my performance…

Thanks for the replies guys, all good points. I want to avoid another failed workout because it is very frustrating and mentally demanding, so I am planning to do this:

  1. do a proper ramp test on trainer
  2. do another 20 min power test outside to see if the previous result wasnt a one-off
  3. focus on sweet spot workouts with ocassional vo2max workouts, since these will not give me trouble completing them

If your outdoor power test goes well, and it does look like indoor temperature is affecting ability to perform high intensity intervals, you can (if you already haven’t) look into Lasko fans.

A quick search of the forum should find links - and if you’re in the UK, this thread has a useful alternative.

That said, I’ve found that during summer, the air-blower still isn’t enough to get what I need to out of vo2 max sessions. So I’d also look into hills and loops for doing these outdoors.

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hmm that air mover looks impressive, thanks for the advice!

So I did a ramp test yesterday with a result of 268, which seems to be pretty close to my calculated outdoor ftp (273).

I have also monitored the difference in watts between P2M and direto, I am surprised by how close the numbers are. The last 3 steps have an average power of 320/335/350 on direto vs. 321/335/351 on p2m :slight_smile:

So I guess that tells me 2 things:

  1. my fatigue resistance sucks, as bobmac has suggested, so I need to get back to sweet spot workouts
  2. I should get that air mover thing, because overheating seems like a real issue

Definitely recommend the air mover.

To test your fatigue resistance, Lamarck is a good marker, excuse the pun. 4x10min at your supposed threshold. If you can do that without reducing intensity, then all is well. If you can’t, then take your average power from the 4 intervals (try your best not to stop, just reduce intensity) and use that as your FTP for sweetspot and threshold sessions.

Generally I find the ramp test tracks well to vo2 intervals, so I’d tend to try to complete those at 268.

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