# % FTP vs time relation

How long can average person sustain (theoretically) 90% FTP, 80% FTP, etc … Is out there any graph of this relation?
Example: If I plan 3 hour ride, what average %FTP can I aim at?

I put this info into my chart:

I pulled that info from the “Description” section in the following link:

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I somewhere heard the following formula which seems like a reasonable rule of thumb giving some good starting point of orientation:
0.95^hours * FTP

Rizzi, what is ^ and *

Thanks

It’s the math meaning 0.95 to the power of “hours”, the multiplied by the rider FTP.

Ex: 0.95 ^ 1 hour X 200w FTP = 190w Average for the 1 hour

Ex: 0.95 ^ 2 hours X 200w FTP = 180w Average for the 2 hours

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^ = to the power of / exponential
“*” = times

So with 300 FTP a ride for 3.5 hours would give
0.95^3,5 x 300 that is
0,835665780138059 x 300 = 250.7 Watt as coarse orientation.

Or simply 0.95^hours is the percent value for your FTP of that duration.

Of course it depends on the type of ride / terrain and so on if it’s a good match. But as said at least a good starting point.

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Thanks Guys, that makes sense.

I do have another question - hope the OP does not mind.

I’m working with Virtual power, so don’t have a power meter. So if according to the above calculation for my target event is say 2 hrs @250 Watts - could I use my HR. I understand that their is a lag and its not as accurate as power but say I did 3 x 20min intervals at 250 Watts on my trainer - could I average out the HR from the 3 intervals and use this as rough guide to pace by.

With my limited experience it seems like a sensible rough approach but you should keep in mind that HR depends on many factors and could also be off that day. So with experience you might want to additionally or instead go with RPE.

I think it depends on each person and remember in the podcast some favored not to see HR so not to be influenced by numbers getting in your head.

@mcneese.chad might have some more elaborate info.

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@Rizzi, you nailed it. I’d just take some mental notes on the trainer and play a bit outside. Know the variables and take as much as you can into that, and learn what really works for you.

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