5 mile mellow round trip ride to grab coffee (with power) shows TSS almost as high as some 1-hour TR workouts

Basically I rode ~10 minutes there, hit lap button, sat around for an hour, then rode back same ~10 minutes. No hero sprints or anything like that, in fact I was keeping it quiet because I had a TR workout scheduled for later that day. Looked at TSS and it is showing as 55, huuuuh??? Goddard is 57 and that’s a much, much, much harder effort!

Maybe numbers are skewed because of a long pause in the beginning of lap 2 and somehow the way TSS is calculated isn’t handling such a thing well? Power zones correctly shows over an hour of “coasting” so that’s there. Calories are at 170 so reasonable. Duration in the interval table is also showing correctly but start/end is revealing the “sit in the coffee shop” time.

why are you including a “5 mile mellow round trip” in your training data?

it was a coffee run. it doesn’t have any impact that matters on your training – so don’t use a powermeter for them. just enjoy the coffee trip.

I doubt he’s built this ride into his training schedule, he probably noticed this being odd and thought he would ask the question of our highly esteemed peers.

This is weird. The calculation for TSS is (time in seconds x NP x IF / FTP*3600)*100. For some reason this ride got a normalized power of 199, so that’s throwing the whole equation off I think. I don’t know why it didn’t count all the zeros in the middle. My completely naive opinion is that because of the very short nature of the ride with the long break in the middle, the system just wasn’t able to resolve the averages and trends. Did you upload to Strava or Training Peaks, did it give a TSS score?

Its an artifact of the NP calculation which goes:

  1. starting at the 30 s mark, calculate a rolling 30 s average (of the preceeding time points, obviously).

  2. raise all the values obtained in step #1 to the 4th power.

  3. take the average of all of the values obtained in step #2.

  4. take the 4th root of the value obtained in step #3.

did you recalibrate the powermeter before the trip back?

lap 2 makes no sense.

anyway, I"m going to double down. If this PM works fine when you calibrate and then train, then so what if it read wonky on a coffee run. don’t use a PM on a coffee run.

Yeah, it’s like the NP figured only on moving time, but the TSS was figured with that NP on total activity time.

[EDIT] NP of 199 seems plausible given the considerable number of surges on the back. But the moving time was only 19.3 minutes. So the TSS should be 100*( (1.07 x 1.07 x 19.3)/60) or 37


Apparently TR doesn’t know how to properly calculate NP.

Beer and Burrito rule applies here

By the way, another discussion we had back then was about two-a-days. This might have even more applicability to triathletes, but back then we were only concerned about cyclists who did two-a-days. As you’ve noticed, concatenating two rides gives you different TSS than two separated rides. I don’t think that has ever been satisfactorily handled, nor have 24-hour rides that cross over midnight. We did come up with a rule of thumb that if the two workouts were separated by enough time that significant (we never determined exactly what that might mean) recovery could have occurred, then they should be separated into two rides. Empirically, that meant that if you stop for a stop light or to wait for your riding partner to catch up, you don’t split your ride into two. On the other hand, if you do a ride at 8 am and another at 4pm, they should count as two rides. That became known as “the beer and burrito” rule.


I was just making sure power meter still works good, haven’t used it fora few weeks. The sync happens automatically so yeah, I’ll delete it so my weekly TSS is correct. The point is I shouldn’t have to do that.

Power meter is Powertap G3 so very unlikely it’s off.

Cool, this makes sense and I learned how this really works. Thank you!

TSS is based on your NP and NP is based on your FTP. The issue is that short duration efforts have little correlation with FTP. This ride looks like you smashed it for 10 mins to the coffee shop and then smashed it back. So you’re calculating a NP number from basically 2 * 10 min sprints, which isn’t what NP was designed to accurately measure.

TSS is just an extrapolation of that since TSS = (IF)2 x Ride Time (hours) x 100. So your sprint efforts artificially inflate the IF of the ride and then it just multiplies out from there.

Here is a deeper explanation if you’re interested.

I split that workout in Strava into 2 without the gap, and they evaluate into 19 and 13 TSS. Can’t import them both since they claim to be duplicate workout so had to do import/delete on those. Also TrainingPeaks TSS for that same ride (coming from Wahoo Android app) is 33 without any modifications. So TSS of 55 is a fluke.

I didn’t hammer the coffee shop run, in TrainingPeaks overall NP shows as 153 which is well below my FTP.

Send email to support@trainerroad.com with a link to your ride - I’ve had a few rides with bad TSS in TR, but good TSS in TrainingPeaks/WKO. They should be able to help.


Yea, sent e-mail with the original .fit file, thanks!

Thanks for the super useful link @julianoliver
I started the thread thinking I’m just not understanding something about TSS, and yea maybe this wan’t what I wasn’t understanding but I was not understanding a bunch of other stuff, so no regrets!

NP isn’t based on FTP.

19 + 13 = 32, versus 33 when treated as a single workout. So much for RATSS or the “bean and burrito” rule.

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Consider how small the amount data is, we should expect a very small delta. If this was an hour long ride with a two hour break then another hour long ride, the burrito and beer effect would be greater.