Indoor endurance workouts soreness

But what was your cadence? I’m not just saying indoor is smoother for power, I’m saying indoor is less smooth for cadence and that indoor leads to more muscle soreness. I have a feeling the reason my candence is less smooth indoors is why my legs hurt more

Is your cadence captured on the same exact device in all these rides?

Different workouts, different cadences. In Erg I’ll settle on a cadence, something between 80-95rpm, and in the early days of using TR kept pushing cadence higher and higher until I did an entire workout (sweet spot and endurance recovery week) at 95rpm.

In your situation, my first suspicion is that its related to little chainring, Erg, and your pedal stroke. My recommendation stands, I’d suggest doing an endurance workout in sim mode on Zwift or RGT. That might be a hassle - RGT is totally free, Zwift has some free mode - so my alternate suggestion is trying standard/level/sim mode if possible (I think standard mode with TR is no longer supported on 2018 Kickr, if Kickr firmware has been updated).

both used a pioneer power meter so magnet based cadence built into it. Same bike and same fit. Indoor on a kickr2018

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OK, just checking. I took a quick look at your data above, but need more time later tonight.

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1 hour indoor vs 6 hour century? Ok, I’ll look even though Strava is the worst at power graphing and scaling…

Outside 6 hour century, randomly zoomed into about 8 minutes, looks pretty natural:

And inside:

Kinda looks like erg and little ring, possibly a little too smooth (unnatural), but average power is only 85% of the graph above.

Ok, here are some graphs where I made sure the average watts are about the same, and set the y-axis to use the same range:

Those are also about 7 or 8 minute windows.

Inside and outside look about the same, and the power standard deviation around average is 15-21 watts.

From one of many posts I made on the topic: Stages power meter "jumpy" - #13 by bbarrera

My first guess, even with the Strava handicap, is that you are comparing unnaturally smooth power to outside power. But it could be something else, hard to say when Strava does the graphing and you can’t run basic statistics.

Hope that helps.

Thanks. But I was also looking at cadence where that seemed to be less smooth inside and the combination of the two metrics which leads me to a possible way to explain why indoor erg mode makes my legs more sore. The soreness is what I care about. Not saying I want to avoid it if the soreness means some bottleneck in my performance is increasing but then trying to understand that bottleneck

I’m getting eye strain from looking at Strava, @enki42 so here is a quick outside (Jan 2021) vs inside (Jan 2020) from my files…

Outside 4 minutes endurance pace, about 17W standard deviation around the average power (about 172W):

Inside 4 minutes at lower endurance power, about 7W standard deviation around the average power (140W - when ftp was lower vs above):

That was dual recorded, TR PowerMatch via BT controlled the trainer, BUT the power trace above was recorded on Garmin 530 via ANT+ connection to Stages gen3 dual-sided crank power meter. Less variations in power and cadence. Picked that inside ride because it was around the same cadence.

What I’ll say is this - after two years of using Erg I concluded it generated some unnatural feelings, and I was falling into what felt like a trap of reinforcing habits that didn’t translate to outside. From that conclusion I decided that focusing on the fundamentals was more important. So I stopped using erg, and never looked back. When I jump on the trainer now, it feels like outside (sim mode).

Don’t be afraid to experiment, and good luck!

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FWIW, I find small ring ERG is harder as far as “soreness” is concerned. I ride big ring as that is the ring I ride outside unless I am climbing a steep incline. I use the KICKR 2020. My wife finds ERG small ring harder so she just uses sim mode. I will use small ring IF I am working on climbing mode.

Two hypothesis:

  • This could be another case of using an FTP that’s too high, and you are doing Tempo and SST instead of z2.
  • your seat is too low?

Indeed. I started with a indoor FTP few months ago and that is another difference in muscle load after an endurance ride then before. Maybe it is also a trainer issue. I have a tacx Neo and a Tacx FLux. With my flux (when i compare with my favero pedals) under 200W my Favero gives mostly 15W less. This is not the case with my Neo. When I go higher in wattage this reduces. And if I compare this ‘feeling’ with an outdoor session, the Flux seems more natural then the NEO in Z2 range.

Endurance workout are pretty tough for me on the trainer as well. One key aspect being that they usually fall directly after a tough workout and the legs are fatigued. This applies outside as well though.

The other thing I noticed with ERG is that I build up unnecessary tension in my lower and upper legs. Almost like resistance against the power enforced by the trainer. I can drop the tension by focussing on it without dropping power output. I assume this affects RPE and soreness. Anyone else noticed this?

100% agreed, that is the reason (and apparently the only reason) that caused me muscle soreness almost to the point that they became chronicle.

There are two issues listed in the post to which you replied. Is the “100% agreed” for both of those, or one in particular?


OK, muscle soreness. Which muscles? Hopefully it’s not knee pain, or I’d say stop immediately and get a fit, because something is seriously wrong.

There might be fatigue, but soreness, I’m not so sure about.

Firstly, turn off ERG power smoothing in the Wahoo app, so you can see more real power fluctuations.

Secondly, try turning off ERG mode.

That’s more fatigued, I think. Honestly, it’s my main complaint about doing interval outdoors, too many micro-breaks.

Hopefully it is as you say, muscle fatigue and not due to something more.

I would turn off ERG mode and try varying power and cadence. But, if you really want ERG, that’s fine. Shift. Up and down, different gears, different cadences. Change your pedal circle. Quads for 10 minutes, slide, for the next 10, kick over the top for the next 10, etc.

That’s not a big deal.

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  • That’s already been done and mentioned in his OP.

It is seen as “normal” power in the rides he linked:


The FTP being set to high for indoor (sorry).

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Off topic - do you have this graph/data that you could share publicly?

This is something that I’d been thinking about earlier this year.. I was suspicious that when you were in a little gear up front in erg mode that force would be applied equally throughout the pedal stroke (function of angle versus applied force would be constant), rather than variable like actually on the bike. And that this may be part of the reason why indoor FTP is lower in many people. And why using the small ring in erg mode is more difficult. However I couldn’t find any actual data on this.

If you have data that suggests that the standard deviation of power as a function of angle is much lower in the small chain ring than the big chain ring even in erg mode, this would prove that pedalling in erg mode (at least in certain gearings) is fundamentally different physiologically than on-bike, and would explain a lot of things.

This has been mentioned multiple times above. if you take a sweet spot ride of threshold ride of an hour with an average wattage of X and you do an endurance ride with an average of X (i.e. both are the same average wattage) it would seem like the endurance ride should be easier in that if you exclude the warmup aspect keeping a single wattage output should be easier then going hard with breaks. Now in my case the average wattage of the endurance rides is ~15% lower.

Plus the soreness sets in early at around 10 mins in and only very slightly increases as the duration increases. Harder efforts aren’t less sore, but there is still a big difference in how soreness from the endurance efforts goes away in under 30 minutes after a workout leaving my legs feeling “normal” again like no reason not to jump on the bike again. With the harder efforts the soreness stays around like I just did something hard that I need to recover from.

Thanks. This was sort of the main reason for asking. In that its not bad and I know there can be pain to training so if its normal then I’ll just accept and move on.

Already have been fitted. The main drivers of my legs are what is sore, so quads. And now that I switched from 172.5mm to 165mm cranks my hamstrings and glutes feel it a bit too, but still mostly quads. (Part of the switch to shorter cranks was to get more muscle activation of more then just my quads being the main driver which seems to be happening but its only been a few weeks now. This crank length change is a seperate thing as the soreness is the same before and after the crank change.

The fatigue part only happens over an hour into the workout. The soreness starts much earlier. SMO2 (as measured by a Moxy) doesn’t show anything happening when soreness starts or fatigue setting in.

If this was from something like compartment syndrome I’d expect my smo2 to drop more as the pressure would decrease blood flow. So hoping this is more an endurance thing that is trainable

Did that a long time ago. Also was using power data from my pioneer power meter cranks. (the new 165mm cranks don’t have power but just got Assioma pedals to become my main source of power but not in use yet)

Without erg mode I tend to not push as hard and the metal burden of keeping my wattage up makes it much harder to do workout. (guess I’m not really a natural athete and too lazy…)

Then turn it off, over time you’ll get better at it. FWIW, without ERG, my power is pretty flat, on a trainer. My coach thinks I’m using ERG, when I’m not. It’ll fluctuate when I’m doing other things. I have a leg imbalance and part of it is due to me lifting my left leg more than my right, that I’m trying to fix.

Vary your cadence, and vary your pedal circle. Over time, you’ll get better. Your soreness is probably just like lifting weights after months off. It’ll be sore for a a few days, and then magically stop. Hopefully that’s what you’re describing.

What is surprising is that it’s the quads, as that’s the primary force outdoors, so you should be conditioned already. I don’t know if you have a PM with Garmin cycling dynamics and can analyze your pedal circle to compare indoors vs outdoors.