Further investigation in my efforts to nail down a reasonable CP30 figure and I think I've made it now. I could have gone on tonight I reckon but when I reached just under 25 minutes into the 315W effort I could feel my respiration becoming more laboured and my HR was starting to enter VO2 max training territory, I'd reached I believe my ventilatory threshold. So, based on this I knew I was working slightly harder at that point than I need or want to for my threshold efforts, so I called it a day.
So, I got to just under 25 minutes at 315W and I have previously managed 310W for 30 minutes, on this basis I'm going to fix my current CP30 type efforts at 310W and I'll move into the next phase of my training next week. I'll probably repeat the 310W 30 minute effort first just to make sure that the first time I did it wasn't a freak result and make sure that I can in fact repeat it as required, because required it will be!
It's interesting to find that I can now ride for longer at a higher intensity, there is no doubt about that, I think something is working :-)
If you compare the HR profile below for tonight's session with the one done on Monday 08.12.2008 you can see what a difference the extra 15W makes when working round about one's FTP, much less comfortable!
[Uploaded 18/12/2008 22:21:18]