Sunday, November 9, 2008

New FTP!

Good news bad news...

After doing a VO2Max test a few weeks back I decided that my Ergomo's where reading too high. At least WRT to the Computrainer at the Lab.. So I repeated the ramp test here on my Computrainer, using my P2c with Ergomo. And then compared the results... 

It showed that P2C Ergomo was reading perhaps 20% to high in the "interesting" range (200-350). 

So I replicated the test using the Soloist with it's Ergomo. Similiar, although possibly not quite 20%. 

So off to the track and drag home the track bike and test with it... There the numbers matched reasonably well, although possibly slightly low.

So mea culpa... I now have a good explanation of why the numbers on the TT bike where slightly higher than the road bike. And why both the those where higher than the CT or Track... 

I had assumed, since the number from the two road bikes (Soloist and P2c) where reasonably similiar, that they where fairly trust worthy.. Apparantly a bad assumption.

I'll do a separate post showing some sample results and explaining the test regime. The results are that I have reset the K-Factor's on each of the Ergomo's to adjust them down (or up) as appropriate:

  1. Track 181 -> 182
  2. Soloist 184 -> 165
  3. P2C 196 -> 164
This assumes of course that the Lab Computrainer I have is accurate. Not necessarily a great assumption. But the main excercise is not so much absolute accuracy as having the all of the devices I use provide equivalant data. I'll also point out that a) it is a Lab CT, b) it's reasonably new and lightly used (<2years)>

The above adjustments should mean an FTP in the new regime of about 280. I"ll need to do some testing to confirm that one way or another.

The other problem is that CTL/ATL/TSB for the last few months (since I've been back at the track) are off significantly. If the track bike was under reporting as compared to the FTP from testing on the road, then TSS points computed and therefore CTL/ATL/TSB are too low. Especically true on the track where we see short and intense efforts. 

Going forward we'll be ok. But it takes some work to get the past few months corrected. The simplest approach is to simply use the "new zones" feature to set a new FTP prior to each weeks track or road. Moving it up and down to match. The end result was to move current CTL from about 70 to 79.

Today was the first day out on the re-calibrated Soloist... Got rained on doing Ford Road at L2/L3. The legs where a bit tired from doing the (5) ramp tests yestered (start at 100 and ramp at 60w/minute until failure, about 5 minutes...) 


Tanj,Uschi&Vladi said...

Thank you very much for posting your protocol. My 3 Ergomos do not agree with each other or my CT. Some are wildly off. I have been simply riding long steady state intervals at 300w (CT in erg mode) and making adjustments to each Ergomo's K-Factor.