Being winter, I decided to experiment and lose my Z3-oholic ways for a while. So 90% of what were Z3 trainer rides have been Z2 for about 6 weeks.

I didn't really like this to begin with. No endorphin buzz. I found an hour of Z2 to be weirdly fatiguing in the upper legs.

After 4 weeks, I noticed that I was becoming more efficient in Z2. Lower HR at fixed power and maybe a little more power at VT1. Now at six weeks, that trend continues. I haven't been doing any HIIT, so this really hasn't been polarized training, per se.

This week I thought it was time to dial things up and get a sense of where I'm at performance wise and figure out what I want to do for the next six weeks -- which is roughly when I'll be able to get outdoors again. And I like what I see. The best quantitative A/B comparison I have is on a 5 x 3 minute HIIT session with 3 minute recoveries, 30 minutes total. I did this workout yesterday and flat out killed my old performance from November. I'm up 7% on average "on" power... but I'm up 20% (kJ) for the whole session. My ability to continue to put power down during the recovery phase is just *amazingly* improved and I was able to hit the same average power for all five intervals, which I have never done before.

I'm not training for racing, but I do have a goal this year, which is an honest 25 mph 1 hour ITT on a closed course. Well, it's loftier than that, even. It's 25mph on a 90% effort, because I really don't like to suffer all that much, lol.

So the plan is obvious. Keep the Z2 and add HIIT twice a week. I'm going to be fast this year, yeeeee-hah!