Jorge's Plan Cycling Zone Calculator question

The CP method looks at a short duration (3 to 5min in your case) and a long duration (20min) and looks at the decline between the two and predicts a power that you can hold for a "long time" based on that decline

You increase your short duration power and left your long duration (20min) power the same. So it now sees a bigger decline and predicts a lower CP

That's a simplistic view of it

The more "complete" way is to plot Energy on the Y axis, and duration on the X axis and the slope between the two points is your CP

5min@300watts = 300sec*300w = 90000Joules
20min@250watts = 1200sec*250w = 300000Joules

Slope = deltaY/deltaX = delta energy/ delta time = (300000-90000)/(1200-300) = 233 this is your CP

Now boost that short duration to 320watts
5min@320watts = 300sec*320w = 96000Joules
20min@250watts = 1200sec*250w = 300000Joules

Slope = deltaY/deltaX = energy/time = (300000-96000)/(1200-300) = 226 this is your CP

So 5min power went up, but CP came down

Thanks guys! I love this training plan!

Hello again everyone,

I've been monitoring my progress since I started this plan in January and I am certainly making good bike fitness gains. My next question is about CP in his calculator. I'm thinking CP in his calculator is also FTP?

Anyway, my last 20' all out test yielded a watt value that's 3 watts higher than the CP calculated. During the test I ran a about a month before, my 20' all out test yielded a value that's 4 watts higher. Pretty close on both tests.

I calculated 95% of the average power output of a 20' all out test and that looked like a power output I could sustain for an hour (FTP) but the CP value Jorge's plan yielded seems too high to be sustainable. In my case, Jorge's CP value is 7-8 watts higher than 95% of 20' all out test value (FTP). I guess I can do a 60 minute test for both values and see which one is fits better to calculate my zones.

I'm confused because many tests I've found online say to use 95% of 20' all out test average or normalized power to get FTP which I thought would be really close to Jorge's plan's CP but it's not. Can anyone help me understand the differences between the 2?

Thanks,
Roland

In theory, FTP and CP are not the same

FTP is the higher power a rider can sustain in a quasi steady state for an hour.
CP is the power a rider can sustain for a "long time". and is the result of a calculation

FTP is measured by going out and doing something like a 1hr TT. There are ways to estimate FTP, but they are estimates. You can get an idea of how good these estimates are here : http://alex-cycle.blogspot.ca/2008/05/the-seven-deadly-sins.html

The CP model allows you to calculate a theoretical power for any duration of time. From the CP model you could theoretcally calculate the power you could sustain for 45min, 1 hr..... Your CP is usually less than your FTP. I believe CP and lactate threshold correlate well.(I mean MLSS but that is overcomplicating it)

So training peaks sets zones based on FTP, Jorge (and others) set them based on CP. Jorge also sets them for HR based on lactate threshold HR

The 95% of 20' is a way to approximate your FTP. When that method came out it actually specified you had to do a 5' blowout before the 20' but some decided to (IMO wrongfully) drop that component. This leads to over estimated FTPs for some people

The 5/20 CP test can work well IF the tests are really done to maximal effort and this requires some experience in pacing and target setting.

If your CP is higher than 95% of your CP, I suspect your CP is wrong and I suspect you under performed in your short test.

But it probably doesn't really matter. For training purposes, being a few watts off is not a big deal. Your coach (in this case Jorge) should be giving you workouts you can do. If you can't, then probably your CP is too high and you need to adjust. If you made it through that 6x4@105% with 45s rest, I suspect your CP is not far off.

The big big big mistake you can make is take what may be an innaccurate CP and try to do a HIM at 80% of it.

Stick to CP, learn to test through experience and you will zero in on the right zones. Specific workouts like that 6x4 will give you an indication of whether your CP is too high/too low..

Edited by marcag 2017-03-17 3:17 AM

Ahh okay. Makes sense. Thanks guys. I'll stick with the current CP since I can hold the 6x4's.