I’ve been happy with the quality of AI workouts and have accepted that small 1-2W fluctuations in FTP predictions are not worth losing sleep over. But every once in a while I get a headscratcher. Would love it if one of the TR folks could take a look.
I had a 10 day vacation on my calendar near the end of a 30 day window and my FTP was predicted to drop from 219 to 215. Fair enough. With a VO2 w/o scheduled two days after coming back home I manually added an AI-selected Endurance 1.0 ride the day before it just to warm up the legs. Adding this ride triggered a new VO2 w/o which makes sense. And FTP prediction went up to 216. All fine.
Today I did Thimble and finished all the intervals with no backpedaling on the recovery intervals and rated it hard. But the 50 second work interval averages are consistently below target watts. This has been an ongoing issue for me on rides with intervals under 60 sec. I’m on a Kickr Bike Shift and doing the workouts on Zwift. I’ve seen posts about Zwift reporting lower numbers in ERG mode for shorter intervals but usually this has only dinged me 1-2 TSS points, which I’m not losing sleep over.
But Thimble shows a 4 point TSS drop and VO2 Max level of 4.9 vs the 5.3 target. No huge cadence spikes/dips in the work intervals. My interval averages were mostly 272W for a 278W target. But okay, it is what it is.
The headscratcher is that post w/o and only two days before my next FTP, the prediction has dropped from 216 to 210. That seems pretty steep for a completed w/o with power numbers at least in the ballpark of the target.
And bigger picture it means that over a 4 week period, with travel limiting me to 3 weeks of workouts, on Thur my FTP is going to be back where it was 8 weeks ago. Looking at my calendar in February, 3 weeks of workouts (1 week of travel) with full compliance got me from 210-219 but now a similar training schedule drops me from 219-210. That just seems odd. What am I missing?
