Attempted ZCIs and failed embarrassingly, even after dialing down my power target based on reduced FTP (vs. last fall, which was the last time I did ZCIs). The first interval was already hard, and I pretty much gave up during the second one. Since the Garmin was still happily beeping away, I sort of finished the workout, keeping the work intervals at least near the middle of Z4 - but nowhere near where I wanted them to be. Looks like I have a ways to go...