Time to do a bit more threshold work and by way of a change I did 4x9' efforts at 100+% of FTP which, all things considered, went pretty well. I received a query from a mate of mine about my choice of the 9 minutes for the interval length and my reply is shown below for anyone that's interested:
I get a bit bored of 2x20s for one thing so yes, these are a bit of variety and also go above FTP at times. I also find that the hardest part of an FTP effort is the first part when HR is low and one goes into oxygen debt which then has to be repaid, and I think this is an excellent training stimulus. This 4x9' session means there are 4 such sections in the training session rather than the 2 you get with a 2x20' session and the recovery periods are only 3 minutes, so really quite a good "real life" session. Another factor is that for general road riding in the UK most climbs take less that 10 minutes so 9 minute efforts at or above FTP are ideal. Seem reasonable?
That's my rationale anyway, a change is as good as a rest, didn't feel like that though!
All in all the session went fine and delivered the kind of TSS I was looking for to maintain my steady progress.
To review the session data: click here.
ATL: 84.5 CTL: 76.1 TSB: -9