So I tried to do 2x20s for the first time (at least on my own) yesterday, and I failed it!
I had to use the gym bikes, since our team doesn't have access to the spinning room until October, and my trainer sucks. I warmed my legs up for ten minutes, and then got going. I turned the resistance up until I was having a hard time spinning at sub 80 rpm, and then adjusted it so that I can still feel that at 80rpm. I forgot my heart rate monitor, but the machine had one (that was pretty accurate).
I couldn't go past 10 minutes. By that point, my HR was at 175 (which is about 95% of my HRmax, so far as I'm aware right now), and I was spinning between 77 and 80 rpm. I recovered for 8 minutes, and went at it again. I had a much more difficult time getting my heart rate up than the first, predominately because my legs were really tired (or I may have spent too much time in recovery). It took about five minutes for me to get to 170, and even at that point, I couldn't hold it sustainably. After that, I recovered for a minute or so, and then I did five 10 second sprint efforts (each included a minute of recovery). I tried to just "disconnect" my legs from my head, so that I can deal with the pain a little better. I think I pushed my heart rate to at least 182, possibly 185, and I hit a max cadence of 146 rpm at that resistance level.
I couldn't measure my power output, since the machine only had METs, which seems to be the amount of oxygen I'm moving. If it counts for anything, I held it between 14 and 18 METs. I reached somewhere around 31 METs in the sprints. I wish I had a power meter, since that seems to be more useful for cycling.
I know now that I have the potential to do better, so what I'm planning on doing is increasing each interval by either 30 seconds or a minute each time I do it. I want to slowly build up to being able to do 2x20s, since I know that can help me immensely in doing better in the time trials. I'm thinking of doing this every Monday (and possibly on Sundays, though this Sunday is out) until I hit my intensity training, which I will do this twice a week consistently with other strength-building workouts.
What do you guys think? I talked this over with one of my team members, and he suggested that I find a resistance level that lets me spin this at 90 rpm instead of 80. The thing is that I feel that in my informal TT efforts, I feel most powerful when spinning between 85 and 90, while using 53x17 or so. When I spin faster, I don't transfer power as well. Should I concentrate on improving this?