always comparing to coggan lol … it has nothing to do with “sort of low tempo / high endurance” coggan ftp fail zones…
stop comparing it to other zone systems, this is based on metabolic events.
your real z2 can be walking pace. or it can be at a very high velocity close to your max. you can ride your coggan endurance or tempo but you probably far off of your real z2 …
and it is not connected to fatmax. even though for a majority there is a correlation. you have to look at lactate, substrate util and so on
It seems Moxy hasn’t become popular for a lot of reasons. I use them. It’s a cool device, but I don’t think it’s a good replacement for lactate testing.
Andri Feldmann is doing a ton of work with Moxy though. He has some good webinars and papers. However, the “Critical Oxygen” concept is a bit nebulous to me.
And then what performance gain do you hope to gain once you know you’re riding at XX% fat utilization?
This is all a hell of a lot of effort for the average athlete to go through to be told to ride +/- 10W from where they probably are riding already, IMO. But if you’re not average and you wanna know, then go to it. There are some users here who know what they’re doing with this stuff, others who have done it before and stopped for various reasons. I’ve not seen tons of evidence that ISM’s zone setting is better. It’s just way more complex. (Kinda like INSCYD testing in that way, which makes you feel pretty fancy, but is rooted in old/outdated/bad science and costs a lot of money.)
I’ve found the Inscyd thing a little frustrating. I’ve probably spent hours listening to podcasts on how this was the greatest thing ever and the secret to unlock individualized training - just train the VLAmax. Now we are finding that VLAmax is probably BS.
What I find weird is that some coaches that were selling it, quietly dropped it without telling anyone that is was BS. They probably concluded themselves that it wasn’t worth $200 per test but very few people are willing to speak out.
And other coaches are still selling it probably because it’s a profit center or client referral system for them.
INSCYD has a good marketing team, and they invest in trying to get coaches onboard through trials, talks, and free educational materials (cough). I really like the guy I was talking to, but I stiff-armed him for about six months while I dug into the science behind INSCYD and came to the independent conclusion that it’s based on BS. They moved me over to a new sales guy and I’ve talked to him precisely once, it’s never come up since…
I can definitely see how they get newer coaches looking to grow a client base and income on the hook. They dazzle you with info, quotes from sponsored athletes and scientists and coaches with vested interest, and give you enough free stuff to string you along. They make promises about sending athletes your way for testing, etc. I would’ve been one of only two coaches in San Diego county offering it (the other being Jim Vance, whom I respect tremendously in the world of triathlon), so there’s an attraction there.
But this is why I am happy with my station in life: semi-retired, other business interests, coaching because I love it. I’m not stressing about income and how many clients I have at any given time. I want to be fairly compensated for my time, but otherwise I’m not trying to put my kids through college this way so I don’t have to sell stuff I don’t believe in (or coach clients I don’t like coaching) to make ends meet. It’s a good place to be as a coach.
FWIW, some of the discussion in this thread reminds me very much of my dealings with the good people at INSCYD… just making things unnecessarily complex for reasons I don’t want to speculate on (INSCYD wants to make money, obviously).
Yeah, INSCYD…I did two tests (in 2021,2022). And every test I was in doubt with the results. Also, how the define Fatmax…unclear. My fatmax would be 30W under my LT1. That seems odd (to me)…
For many people, like me, fat max is well below LT1. In highly trained folks, fat max can be above LT1, which requires far more effort than someone like me to ride at. ISMs lecture PDF demonstrated this.
The highest point of lack of pyruvate in the Mader model (Inscyd, Aerotune, etc) is assumed to be fatmax. The 1986 and 2003 paper explain the pyruvate model.
Good question that I have an opinion about but that opinion won’t help the discussion.
What I will say is determining fatmax or LT1 isn’t only about determining what power to ride at (assuming that is a valid concept**). It is also (and to me, more importantly) about seeing it change after training. So using it as a way to gauge improvement that you would not see just using FTP (or even fully fed power-duration curve).
** what do I mean by assuming valid concept: “ride with power, not by power”…when you say “should I ride at LT1 power”, you are asking about riding by power…I’m staying away from debating that. I’m saying there are other benefits to knowing sub-threshold metrics unrelated to using them to target power zones).
Power-to-HR (efficiency factor) seems to work well enough that it satisfies my data nerdiness. And it’s on every ride. Easier to track if you ride steady on flat terrain or on the trainer.
How do you guys reconcile studies that show large variations in FatMax measurements in the same test subjects on different days? Or that the range of FatMax based on the curves in those models is massive? Or that the fundamental assumption that burning more fat is performance-enhancing is just kinda wrong (for many people, for others it’s fine)?
This is just one of probably 3 or 4 studies that show low inter-day repeatability depending on the protocol, though a couple of studies showing a bit better agreement in lab environments do exist as well.
The present study demonstrates that large day-to-day variability is present when estimating PFO and FATMAX in a heterogeneous cohort of healthy men and women. Moreover, this low reproducibility is consistent across sex and different levels of cardiorespiratory fitness, fat mass indices, physical activity levels, and menstrual cycle status and contraceptive use through the combined pill. Nevertheless, there is little-to-no evidence of systematic bias in measures of peak fat oxidation across two identical testing sessions, suggesting there is no need to conduct a familiarisation session. Additionally, the data analysis approach used to estimate PFO and FATMAX does not appear to affect reliability estimates particularly for PFO, with similar levels of agreement apparent between the MV, P2 and SIN approaches. Collectively, this suggests that future studies should perform repeated assessments to more accurately determine PFO and FATMAX. This will help more precisely prescribe exercise training upon and/or explore the practical relevance of PFO and FATMAX for health and/or endurance exercise performance.
I’m not arguing that FatMax doesn’t exist, merely that pursuit of knowing your individual FatMax is nearly useless to the vast majority of athletes (and that the models, such as INSCYD, that are out there are fundamentally flawed). I hate to see everyday athletes worrying about stuff like this and wondering if they should spend their money and/or time on it. I have zero issue with intellectual curiousity, however, so I applaud people who do the deep dive on their own if their eyes are open!
