Training Load

by mechgt

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Aug 26, 2015

How does FTP affect ATL and CTL?

How does FTP affect ATL and CTL?

Postby samccauley » Thu Apr 24, 2014 10:36 am

I believe I understand the concepts behind ATL and CTL, and the "shapes" of the graphs make sense to me. I'm fuzzy, however, on the "values" on the graph and if/how they relate to my FTP value.

I've read a few articles about FTP, I believe I understand what it is. I found a 55 minute race (a 12K) I ran some time ago (back in 2009). I had GPS data on it and it was pretty close to one hour, so I used Power Runner to calculate my average power for that race. My average power for that 55 minute race effort was calculated to be 363.6. So, I set my "FTPrun" on my Athlete view on that same date to 363.

How does that FTP value, 363, impact the numbers that are shown on my Training Load graph? Does in only impact the zones (low, medium, high, and epic)? Does it impact TRIMP and/or TSS numbers that are used to calculate ATL and CTL?

Thank you.
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Re: How does FTP affect ATL and CTL?

Postby dirk66 » Thu Apr 24, 2014 5:08 pm


I don't know everything on the subject. But your FTP value doesn't influence your TRIMP value since it is a treshold for the power part of the plugin and TRIMP is in the HR part of the plugin. It 'll however influence the tss.
As being a treshold, the FTP is somehow a reference for the produced power during your activities. I don't use this function, but if you lower your treshold, in terms of impact the (effect of the) produced power will be higher. How much? I don't know. However Mecht has placed some reference documentation in different threads in this forum. Maybe you can find the exact answer in the documentation.

Most important tip from me is: listen to your body. The numbers may help you to understand the signals of your body, but don't forget to listen! If your body tells you that you are tired, you are :wink: . No matter if your tss or trimp is lower or higher than during the same run last week.

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Re: How does FTP affect ATL and CTL?

Postby samccauley » Fri Apr 25, 2014 7:16 am

Thank you, dirk66. That's exactly the explanation I needed. I had forgotten that setting my FTPrun value was part of the Power Runner setup, and therefore part of the TSS calculation. So that makes sense. Thank you!
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Re: How does FTP affect ATL and CTL?

Postby the5krunner » Fri Apr 25, 2014 12:27 pm

FTP is best for cycling.

FTP is the maximum power you can do in an hour. It is your Critical Power for 60 minutes (CP60). It is estimated by a CP30 or CP20 + a bit of simple maths.

You then use it for specifying power based training zones. It's good for that purpose and also good for pacing in a race (effectively legalised cheating)


For running how will you know what power you are running at when you are in the middle of a park? (edit 2015: see the stryd power run sensor...super cool). You could do a %age of the pace at FTP to create pace zones but then it seems to negate the whole point of power in the first place.

On a bike you have a power meter (well some of us do)

so it's not really relevant as the previous person said. (although obviously a session based on x% of FTP will produce a trainingload which will THEN be VERY relevant)
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