Yes, see the workout graphic I posted above…They added the one day execution, you still have the option of 2 days.
I’ve seen the same with 6 min. The problem is the bias of those coefficients. I guess nobody needs to be too precise with this stuff.
It says that ramp test measured VO2max correlates r=0,95 with 4min max VO2max calculation.
Are aerotune calculations based on that paper? It sais crossing point (MLSS) deviation up to 20watt and fatmax deviation up to 40 watts…
2 days preferred?
If 2 days…which effort which day?
Sprint + 12 min day 1? 4min day 2? Change days?
You don’t necessarily need precision if you’re doing the same test over and over. Relative differences become more meaningful than absolute values. Since metabolic carts are quite expensive, we use the tools we have available.
Using both of the equations from that paper, I get the same ballpark for VO2Max whether it’s from 4-minute max or last minute of the ramp test. They’re decent approximations in my case.
I honestly don’t know what Aerotune is based off of. The service was strikingly similar to Inscyd when I signed up a few months ago (I never used the service, I just looked).
The VO2Max and VLaMax approximations can be pretty “off”. I think I read that Weber said VLaMax from power can be off by +/-0.25 mmol/l/s. That will give a wide range if you want to do upper- and lower-bound estimates.
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Norwegian, almost to the beat.
(see what I did there)
My LT1 is at about 83% of my LTHR
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Exactly. Also its not so much that it matters if you mess it up and get ridiculous results.
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Will do
It was interesting to hear the interview with scott Johnston on tts he confirmed my suspicions about the early hr zones. Z1 = La1, Z2 goes up to La2.
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I’ve just completed the Skiba book and I see what you mean now. His LT is just above where inflection point definition of LT1. In his words, “you can think of GET, LT, and VT1 to be the same intensity”, but acknowledges a possible difference between VT1 and the other measures based on athlete fitness.
LT = 1mmol above baseline (as @Quaestor stated above). So that is going to be higher than inflection point for determining LT1.
At any rate, he treats anything below ~2 - 2.5mmol to be moderate domain (in the moderate, heavy, severe academic nomenclature). He favors ignoring lactate measurements altogether in favor of field tests and modeling (no surprise there). Also, with training, you “can improve LT from [for example] 70% VO2max to 80% VO2max”. So his LT is definitely not LT1. Although he finds FTP “nebulous” and not equivalent to any actual physiological threshold, he acknowledges its practicality “in cycling circles”. He states: “FTP is probably closer to CP than LT, and would be a reasonable target for long interval training / “sweet spot” training”. Elsewhere I have read he states CP ~5% higher than FTP…but that might have been Andy Jones or David Poole. Can’t remember and someone correct me if wrong. Why care? Because you use an FTP number for pretty much all software or coaching zones, so a valid conversion is useful.
His zones are based on CP, as expected
Periodization
As for Fat util (half the reason we’re talking about all this), he presents a few studies in support of “all good endurance training leads to better Fat oxidation, not just training in a FatMax zone”. It’s duration driven, not affected by intensity differences near FatMax. IOW, .65 IF and .75 IF and .85 IF are all the same. Just do the work.
Now very much interested in looking at this
…as a possible better predictor of performance longer than a few hours (vs CP curve and PD curve, neither of which have addressed these longer durations)
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Good summary. I guess I wasn’t going crazy after all 
. The one thing I want to understand now is how is Xert’s model and improvement over Skiba’s (if at all).
Yep, fax max fallacies. My contention with what KM presented (at the time) is whereas there is not consensus that training at/near fat max is necessary to improve fat util (his contention), there is also no consensus AGAINST it (refuting) either. It’s equivocal. We simply don’t know, other than what both sides concede: do a lot of low-moderate intensity. But that is just as much a fatigue management strategy as anything else.
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Right, reading all of this would push you back to the notion - one Tim Kusick pushed a few years ago in his WKO webinars - of doing your long rides (3+ hours) in low-to-mid- Zone 2 to limit fatigue incurred from those rides. I think there are gains to be made by including “intervals” of higher intensity (say 10-20min of .7-.75, even up into tempo) a few times in a long ride, but in general when I’m programming long rides now I’m still doing them around .65IF to start with and progress duration first and foremost. If there’s a time crunch and you want to go for 90 min or 2h, then get into the longer .7-.75IF or even pure tempo rides if the rest of the schedule allows it.
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. Makes sense. And you’re doing the “cheat” of increasing intensity for duration but in a way that makes more sense than “ok, short on time can’t do long ride I’ll do a Zwift race instead”
And I still zip along at .65 IF most of the time too. Drive that duration out when you can, add tempo if/when maxed out on weekly time or event specific.
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But if you start producing lactates in your long easy rides (with efforts) than you will be riding some times on lactates and your fat metabolisation would be decreased.
This intensity inhibits fatox story, I don’t know (dotted lines are actual ox rates, just saying)
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I think if you look at absolute fat ox, the rate doesnt really go down much until the crossover point which is slightly above the higher definition of lt1. I think ism likes his prescribed zone because it is good at simulating fat and lactate metabolism.
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