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dazzmaster
Joined: 31 Aug 2016 Posts: 35

Posted: Sun Jan 14, 2018 6:05 pm Post subject: TSS formula... 


You have to excuse slightly nerdy post...
Have been thinking this through lately... While the usual TSS formula is
[time in hours] x NP x IF x 100 / FTP
this can be simplified as
[time in hours] x IF^2 x 100
(since IF = NP/FTP)
Is this actually right, from the perspective of measuring one's effort? I guess that putting in say 10% more time should be less 'stressful' than doing a 10% more intensity, and equally doing 40% vs 30% intensity should be less of an increase than doing 90% vs 80%. So mathematically the directions are right, but been wondering if anyone ever did any studies or analysis on the actual relationship... Could not find discussions here about this either, and all you can find on TrainingPeaks reads quite dogmatically...
cheers
d
_________________ '18: Maastricht IM + Big East + Chilterns Middle Distance
'17: Vitoria Gasteiz Long Course + Woburner
'16: Copenhagen IM
'14: Alp D'Huez Long Course


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jibberjim
Joined: 15 Aug 2008 Posts: 8309 Location: Kingston

Posted: Sun Jan 14, 2018 7:48 pm Post subject: 


It's an approximation, it'll never be right for an individual, but equally as an approximation it serves a purpose, you cannot get too beat up about how exactly accurate it might be.
Personally for me, due to difficulty to reliably identify an FTP, I have always preferred HR proxies. Regardless though the inaccuracies do nothing but help identify long term trends.
_________________ Jibbering Sports Stuff


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tin pot
Joined: 08 Jul 2013 Posts: 2570 Location: Bromley

Posted: Mon Jan 15, 2018 7:38 am Post subject: Re: TSS formula... 


dazzmaster wrote:  You have to excuse slightly nerdy post...
Have been thinking this through lately... While the usual TSS formula is
[time in hours] x NP x IF x 100 / FTP
this can be simplified as
[time in hours] x IF^2 x 100
(since IF = NP/FTP)
Is this actually right, from the perspective of measuring one's effort? I guess that putting in say 10% more time should be less 'stressful' than doing a 10% more intensity, and equally doing 40% vs 30% intensity should be less of an increase than doing 90% vs 80%. So mathematically the directions are right, but been wondering if anyone ever did any studies or analysis on the actual relationship... Could not find discussions here about this either, and all you can find on TrainingPeaks reads quite dogmatically...
cheers
d 
No, to simplify the equation as suggested you still need to divide time and 100 by FTP.
_________________ Iron ‘17 16h11, '16 14h30
Half Iron ‘18 DNF, '17 7h39, 6h28 '16 5h53
Olympic '16 3h18 '15 3h33, '13 3h36
Sprint '16 1h17, '14 1h40, '13 2h01
Half Mara '16 2h04, '14 2h07
Trail 10K '16 54:01 '13 54:46


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stenard
Joined: 04 Sep 2013 Posts: 1779

Posted: Mon Jan 15, 2018 9:51 am Post subject: Re: TSS formula... 


Tin Pot wrote:  dazzmaster wrote:  You have to excuse slightly nerdy post...
Have been thinking this through lately... While the usual TSS formula is
[time in hours] x NP x IF x 100 / FTP
this can be simplified as
[time in hours] x IF^2 x 100
(since IF = NP/FTP)
Is this actually right, from the perspective of measuring one's effort? I guess that putting in say 10% more time should be less 'stressful' than doing a 10% more intensity, and equally doing 40% vs 30% intensity should be less of an increase than doing 90% vs 80%. So mathematically the directions are right, but been wondering if anyone ever did any studies or analysis on the actual relationship... Could not find discussions here about this either, and all you can find on TrainingPeaks reads quite dogmatically...
cheers
d 
No, to simplify the equation as suggested you still need to divide time and 100 by FTP. 
No, he's right. His simplification is mathematically accurate. He just missed brackets around the (NP x IF x 100) part. They're all divided by FTP. I've also only ever seen TSS written as the IF^2 version, so I know that is correct.
As Jim says, ultimately it's an approximation of the training load. If your FTP isnt accurate then that will clearly skew the results significantly. And even if it is accurate, taking the Sufferfest 4DP idea, someone who is much more conditioned to work at VO2max levels will in reality be putting much less stress on their body than someone who is not. Yet the TSS calculation would not take that into account.


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iwaters
Joined: 06 Sep 2016 Posts: 417

Posted: Tue Jan 16, 2018 4:59 pm Post subject: 


Best thing to do if you think you can improve on the FTP or TSS formulas is pop a post on Slowtwitch then hide whilst you await the onslaught from Coogan.


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tin pot
Joined: 08 Jul 2013 Posts: 2570 Location: Bromley

Posted: Tue Jan 16, 2018 7:41 pm Post subject: 


iwaters wrote:  Best thing to do if you think you can improve on the FTP or TSS formulas is pop a post on Slowtwitch then hide whilst you await the onslaught from Coogan. 
Steve Coogan would be great, Coggan not so much.
He is a bell end isn’t he? It’s not even that amazing a formula, but sport is filled with those the education system didn’t value.
_________________ Iron ‘17 16h11, '16 14h30
Half Iron ‘18 DNF, '17 7h39, 6h28 '16 5h53
Olympic '16 3h18 '15 3h33, '13 3h36
Sprint '16 1h17, '14 1h40, '13 2h01
Half Mara '16 2h04, '14 2h07
Trail 10K '16 54:01 '13 54:46


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iwaters
Joined: 06 Sep 2016 Posts: 417

Posted: Wed Jan 17, 2018 9:18 am Post subject: 


Tin Pot wrote:  iwaters wrote:  Best thing to do if you think you can improve on the FTP or TSS formulas is pop a post on Slowtwitch then hide whilst you await the onslaught from Coogan. 
Steve Coogan would be great, Coggan not so much.
He is a bell end isn’t he? It’s not even that amazing a formula, but sport is filled with those the education system didn’t value. 
Potato, potarto.
He is a funny old chap. I am sure he has put a lot of effort in to his research and has come up with a lot of useful stuff that lots of people use but he comes across as a weapons grade bell end on the forums. Can't seem to accept that stuff moves on and changes


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