FAQ ~ FTP Variances
Kerry Donovan dishing out the pain...
Why are my FTP sessions different to those on the Drills Pages?
In FTP Development sessions, the 20 minutes interval length challenges certain elements of your heart, lung and nervous system to develop and be taxed in equal measure; this doesn't happen when you keep below certain physiological "trigger points" of time or intensity.
The general consensus now, shows that for trained athletes anywhere from 85% to 97% of FTP for 20 minutes will bring increased rewards. My take on this (assuming FTP is 100 watts) is...
To start at 2 x 15 minutes @ 95% (obviously 95 watts)
then go to 2 x 17.5 mins @ 97.5%
and finish off with 2 x 20 minutes @ 100%
The theory behind this is that over the course of the three week cycle, the sessions have been run at an average of 6 x 17.5 mins at 97.5% FTP.
The overload and adaptation process pushes the athlete to the edge of their comfort zone and brings greater rewards than the previously considered 2 x 20 at 85-92% FTP, for "non-racing cyclists".
Again, if you can ride a 100 watts for an hour then 2 x 20 minutes riding at an hours pace should prove taxing but doable. It's like riding two ten mile time trials at 25 mile TT pace, with a little rest.
If there are real challenges in riding the prescribed levels, it may be that the FTP figure is too high, or the mix of aerobic anaerobic development is not yet ready for such intense intervals.
If you cover up your power levels and ride on feel, then complete the 2 x 20 FTP session to the best of your ability; take the second 20 minute average wattage, multiply it by 1.05 and you'll have your "current" FTP wattage.