Strictly a question of curiosity. Has anyone who has been using Xert for a while done an INSCYD test and compared it’s values to the values that Xert provides us with? I would assume (and hope) that the values would be close.
I have been getting a lot of emails for INSCYD testing and have observed a lot of videos on youtube regarding INSCYD tests, but I am an old guy and don’t race, but do totally enjoy the cycling experience and working on improving despite age. Doubt that I’d ever do an INSCYD test because of cost.
Not with INSCYD but there are some alternatives I recently tried (can’t comment on accuracy of those overall… but also can’t comment re INSCYD) and would say threshold is similar enough (noting my Xert signature is outdoors while the test was indoors).
My impression is that most widely used methods to estimate threshold (however defined) are broadly accurate, but Xert’s advantage is that it doesn’t require a strict structured test (but still requires all out failure which is unpleasant even if not structured!).
The added insight of Xert and other approaches using VLamax (or even just using more points on the PDC without the summary metrics) vs plain FTP is the lower and upper training zones.
The models are of course very different overall too e.g. Xert doesn’t give VO2 max or VLamax, others don’t use PP and HIE. Xert doesn’t actually use simple zones which has pros and cons. Others don’t typically give any detailed training advice or workouts (without a coach) either, which of course you get with Xert.
Re other ‘zones’, fatmax zone was much lower than LTP for me, but that wasn’t a major surprise given the LTP definition, or based on HR and RPE at LTP. LTP is apparently more like tempo in my case. VO2 interval targets were similar enough to Rouleur interval targets in Xert. But that’s N = 1… YMMV