Help me solve the mystery of why my TSS is too high

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DurianGrey
Posts: 43
Joined: Tue Jun 13, 2017 9:57 pm

by DurianGrey

Problem: short interval workouts show more than 100 TSS over less than an hour. This shouldn't be possible.

These are lunchtime workouts, and are therefore short (40-55min). I've done this a couple times, have calibrated the power meter etc. The PM itself is a sram red quarq and has been very solid.

Relevant details for the latest of these rides:

Duration: 50:30
Avg Power: 208
NP: 311
FTP: 275
TSS: 100

Workout was six intervals at 380-400W for 2min each, then another five at 500-600W up a hill for 45s-1min.

FTP was established via a very painful weekly all-out local ride that keeps me at 90-95% max HR for just over an hour. I've done that same number 4-5 times and feel very confident that I'm not secretly hiding 20 or 30 watts anywhere.

This workout was not nearly as hard as the FTP-establishing rides.

I've put the raw data in a spreadsheet and calculated everything manually and I get approximately the same as the numbers above, which are from golden cheetah.

It seems like there should be something simple I'm missing, but searches haven't been productive. What gives?

pwork
Posts: 18
Joined: Wed Mar 02, 2011 7:12 pm

by pwork

TP has the equation as TSS = (sec x NP® x IF®)/(FTP x 3600) x 100. You don't give the IF so 311(NP)/275 (FTP) should be pretty close. I come up w/ 107.5 for TSS. BTW i've noticed this as well on my w/o's...those intervals at 1.5-2.5x your FTP really tack on the TSS pts.

Ninja edit...In theory, you shouldn't be able to do more than 100pts in an hour, but the quantity, duration, and intenstity of the intervals above your FTP add up quickly. Think area under the curve.

by Weenie


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jekyll man
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Location: Pack filler

by jekyll man

http://alex-cycle.blogspot.co.uk/2013/0 ... art-i.html
might go some way to explaining it.
Official cafe stop tester

grover
Posts: 1139
Joined: Mon Jul 26, 2004 1:06 pm

by grover

With lots of short efforts above threshold it is definitely possible to get a TSS over 100 in an hour. I often experience it racing a criterium where you're either rolling at zero watts or pedalling above threshold. However given you're on a trainer you wouldn't have as many zero watt periods which would make it more difficult. Maybe your threshold is higher than you think it is?

DurianGrey
Posts: 43
Joined: Tue Jun 13, 2017 9:57 pm

by DurianGrey

It's not supposed to be possible, though, almost by definition:

https://www.trainingpeaks.com/blog/what-is-tss/
You can earn more than 100 TSS within a single workout (as long as it is longer than an hour), but never more than 100 TSS per hour.

I should have clarified - these are outdoor workouts, not on the trainer. Here's a screenshot of the one in question:

Image

DurianGrey
Posts: 43
Joined: Tue Jun 13, 2017 9:57 pm

by DurianGrey

grover wrote:
Tue May 08, 2018 12:09 am
With lots of short efforts above threshold it is definitely possible to get a TSS over 100 in an hour. I often experience it racing a criterium where you're either rolling at zero watts or pedalling above threshold. However given you're on a trainer you wouldn't have as many zero watt periods which would make it more difficult. Maybe your threshold is higher than you think it is?
I'd like to flatter myself by believing so, but to make TSS for this workout a more reasonable ~80 I'd have to have FTP at 310 or so, which is a massive jump and absolutely, certainly not something I'm capable of per the previously mentioned race-rides.

bilwit
Posts: 928
Joined: Sun Apr 03, 2016 5:49 am
Location: Seattle, WA

by bilwit

grover wrote:
Tue May 08, 2018 12:09 am
Maybe your threshold is higher than you think it is?
I think it's this. Easily hitting 100 TSS in a sub-60 minute workout is indication that threshold is set low and needs to be adjusted accordingly. The normalized power is already 311 for 50 minutes so I don't think a stretch to think that being at or around 300 watts for 60 minutes is out of the question. As I understand it, NP tends to be high when variance is high (ie intervals) and TSS and NP have strong correlation so if NP is 40+ watts over your FTP for almost an hour then naturally TSS should be through the roof. I think if you target 315w for 20 minutes all out you'd be in the ballpark..

TheKaiser
Posts: 527
Joined: Thu Sep 05, 2013 3:29 pm

by TheKaiser

Not a TP user myself, but have read Friel's blog for years and have a general grasp of his concepts. Is it possible that TSS going over 100 relates to certain assumptions that TP makes regarding the relationship of ones FTP their capacity for higher intensity Vo2 max or anaerobic work? That differing relative ability at various intensities is what the Sufferfest claims to capture more accurately with their 4DP model (which I know is based on earlier developments by others, and isn't truely original to them).

There was also an interesting article that just ran in Velonews that covers how rider's phisiology can vary, with some being better suited to steady efforts at FTP and others being better suited to above FTP bursts followed by recoveries. The examples they cite would mean that for the same total power output and elapsed time on a climb, 2 people may have different optimal ways of reaching those performance figures. http://www.velonews.com/2018/05/from-th ... ing_465398

That would mean that some riders would feel less challenged by interval workouts vs. steady state, and others would feel the reverse. Riders of the first type, since they are less suited to steady state efforts, would tend to have a lower tested FTP, but then when they did an interval workout the apparent relative intensity and TSS would seem crazy high since it was set based on a figure determined by their weakness.

DurianGrey
Posts: 43
Joined: Tue Jun 13, 2017 9:57 pm

by DurianGrey

bilwit wrote:
Fri May 11, 2018 6:30 pm
grover wrote:
Tue May 08, 2018 12:09 am
Maybe your threshold is higher than you think it is?
I think it's this. Easily hitting 100 TSS in a sub-60 minute workout is indication that threshold is set low and needs to be adjusted accordingly. The normalized power is already 311 for 50 minutes so I don't think a stretch to think that being at or around 300 watts for 60 minutes is out of the question. As I understand it, NP tends to be high when variance is high (ie intervals) and TSS and NP have strong correlation so if NP is 40+ watts over your FTP for almost an hour then naturally TSS should be through the roof. I think if you target 315w for 20 minutes all out you'd be in the ballpark..
To close the loop, I think you guys are right, and I might be a bit of a dumbass. I went back and looked at all the NP numbers for the last year's worth of this very fast group ride, and assuming the NP is 105% of FTP then I should be around 295-300, and have wasted a year training at lower numbers.

Code: Select all

Date	NP	Time	FTP Est
17/5/16	307	1:00	292
17/5/23	307	1:02	292
17/6/13	318	0:58	303
17/6/27	301	1:05	287
17/7/18	302	1:09	288
17/7/25	289	1:14	275
17/8/1	315	1:07	300
17/8/29	307	1:06	292
18/5/1	312	1:11	297
18/5/8	308	1:14	293
18/5/15	308	1:05	293

DurianGrey
Posts: 43
Joined: Tue Jun 13, 2017 9:57 pm

by DurianGrey

TheKaiser wrote:
Sun May 13, 2018 6:46 pm
Not a TP user myself, but have read Friel's blog for years and have a general grasp of his concepts. Is it possible that TSS going over 100 relates to certain assumptions that TP makes regarding the relationship of ones FTP their capacity for higher intensity Vo2 max or anaerobic work? That differing relative ability at various intensities is what the Sufferfest claims to capture more accurately with their 4DP model (which I know is based on earlier developments by others, and isn't truely original to them).

There was also an interesting article that just ran in Velonews that covers how rider's phisiology can vary, with some being better suited to steady efforts at FTP and others being better suited to above FTP bursts followed by recoveries. The examples they cite would mean that for the same total power output and elapsed time on a climb, 2 people may have different optimal ways of reaching those performance figures. http://www.velonews.com/2018/05/from-th ... ing_465398

That would mean that some riders would feel less challenged by interval workouts vs. steady state, and others would feel the reverse. Riders of the first type, since they are less suited to steady state efforts, would tend to have a lower tested FTP, but then when they did an interval workout the apparent relative intensity and TSS would seem crazy high since it was set based on a figure determined by their weakness.
This also makes sense - I honestly cannot imagine pulling 300W steady for an hour. Lesson learned - I'll pay attention to NP from now on.

bilwit
Posts: 928
Joined: Sun Apr 03, 2016 5:49 am
Location: Seattle, WA

by bilwit

DurianGrey wrote:
Wed May 16, 2018 2:15 pm
bilwit wrote:
Fri May 11, 2018 6:30 pm
grover wrote:
Tue May 08, 2018 12:09 am
Maybe your threshold is higher than you think it is?
I think it's this. Easily hitting 100 TSS in a sub-60 minute workout is indication that threshold is set low and needs to be adjusted accordingly. The normalized power is already 311 for 50 minutes so I don't think a stretch to think that being at or around 300 watts for 60 minutes is out of the question. As I understand it, NP tends to be high when variance is high (ie intervals) and TSS and NP have strong correlation so if NP is 40+ watts over your FTP for almost an hour then naturally TSS should be through the roof. I think if you target 315w for 20 minutes all out you'd be in the ballpark..
To close the loop, I think you guys are right, and I might be a bit of a dumbass. I went back and looked at all the NP numbers for the last year's worth of this very fast group ride, and assuming the NP is 105% of FTP then I should be around 295-300, and have wasted a year training at lower numbers.

Code: Select all

Date	NP	Time	FTP Est
17/5/16	307	1:00	292
17/5/23	307	1:02	292
17/6/13	318	0:58	303
17/6/27	301	1:05	287
17/7/18	302	1:09	288
17/7/25	289	1:14	275
17/8/1	315	1:07	300
17/8/29	307	1:06	292
18/5/1	312	1:11	297
18/5/8	308	1:14	293
18/5/15	308	1:05	293
what about your best 20 minute splits? I have a sneaking suspicion that it's also close to the 300w figure once adjusted (times 0.95). I always found the 20 minute test to be very accurate to define FTP, just "feels right" to determine my zones and pacing efforts accordingly despite never actually doing it flat out for an entire hour

DurianGrey
Posts: 43
Joined: Tue Jun 13, 2017 9:57 pm

by DurianGrey

bilwit wrote:
Thu May 17, 2018 1:03 am
what about your best 20 minute splits? I have a sneaking suspicion that it's also close to the 300w figure once adjusted (times 0.95). I always found the 20 minute test to be very accurate to define FTP, just "feels right" to determine my zones and pacing efforts accordingly despite never actually doing it flat out for an entire hour
It's never been over 301W for a 20min period, which puts me back at 286 or so. Having said that, those efforts were part of these hour+ race-rides and weren't an all-out effort. I've done all-out efforts on the trainer but can't come close to what I get outside.

by Weenie


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