Not sure it affects the practical point, but… A while ago @sryke linked this pod on the ISM thread, I happened to listen to it again this week. Ben Day tells an anecdote (52:45), one early pro season he could being hold 340w for 5 hours but was unable to do 360w for 20 minutes (!) This was in the context of politely critiquing the ISM ‘Z2’ (LT1) approach, he became a metabolic machine but was not at all race-ready. Maybe an extreme example of what can happen at the edges of outlier physiology… Maybe just hyperbole. Interesting little story anyway!
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That would work for me perfectly! 
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Get Inigo on the phone!
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Just some data to chew on for my n=1 given that I have a lactate meter and tested this morning.
HRVLogger using Polar H10 - dfa1 of .75 around 195-200 watts and 134/135 bpm.
FTP per WKO5/intervals.icu/Garmin: all between 277 and 281 and I’ve fed the models well recently on long hard climbs and just can plain feel this tipping point really easily.
This mornings lactate testing with Lactate Plus meter using 6 minute steps only looking for LT1…sorry formatting may look crazy due to mobile:
| Baseline lactate sitting before test: .9 | ||
|---|---|---|
| Watts | Lactate | HR |
| 140 | 1 | 121 |
| 160 | 0.8 | 125 |
| 180 | 0.9 | 131 |
| 200 | 1.1 | 136 |
| 220 | 1.3 | 142 |
| 240 | 2 | 151 |
So depending on definition used……using 1mmol above baseline lt1 is just under 240 watts/150 bpm. First inflection maybe puts lt1 closer to 220 watts/142 bpm. Both are above dfa1 = .75 for me.
Just throwing it out related to estimating lt1 for folks without a meter/testing. Thoughts?
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What happens if you make the steps for baseline a lot longer, say 30 mins each?
This is the problem, there’s no formal definition of the Aerobic Threshold.
N=1 is really uninformative given the chance of measurement error. There’s an upcoming study that looks at this systematically (although not necessarily without bias).
Good points except for the uninformative part I think. A big study will tell you about population averages maybe but won’t necessarily give you insights into individual athletes. The answer probably lies somewhere between with population averages acting as a sanity check.
Perhaps I didn’t worded it properly. I meant 1 sample is uninformative, given the measurement error (contamination, sweat, part of the body variability, etc). A longitudinal study of one individual CAN be very informative, as Mr. @sryke has shown.
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Your LT1/AeT is 205-210ish. Don’t use the 1mmol defintion.
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These must be women, LT2 is absolutely in line with what could be expected. One does also have to consider that you see a wider range of capabilities in the women’s peloton.
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You’re probably right. If I go by feel, right about there is definitely my “happy hard”.
Good post. I listened to this yesterday and it’s actually what prompted me to post about LT1 vs. LT vs. “aerobic threshold” historical language, etc. He’s one of those “try to move AeT closer to AnT” guys.
I think Scott Johnston has great down to earth ideas and I often carry out a variation of the HR-based aerobic assessment thing that he advocates (way more often than an FTP test). If you’ve heard about Steve Neal’s 83% MaxHR assessment, similar idea. Not sure they are going to be anything revolutionary to anyone on this thread, but some might pick up a few ideas.
Of note, he uses the “other” (historical?) meaning of the term “aerobic threshold”. So I think his ideas are interesting, useful, and valid, but I’d hate to see anyone listening get hung up on the different use of that term. His “AeT” is more like Skiba LT. It’s not LT1.
It’s more akin to MAF concepts about what is “aerobic”…below a certain HR which will increase with training as long as that training is below that HR.
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I’m a bit confused. So the only variable would be to lower HR at CP to get those HRs closer?
(I think my threshold HR is pretty constant and threshold power is variable)
curious what that is, because my aerobic decoupling is very low on widely ranging power/durations: a) 50 minute threshold efforts, b) 2 hour tempo efforts (at say 84% HRmax), and c) longer zone2 efforts.
It seems like 4-8 weeks after an off-season, my aerobic decoupling becomes very stable at reasonable sub-threshold efforts. Makes me want to get a sub-max test using gas exchange.
To follow up, still seeing gains at LT1, approx 10W per month at the moment. Another month and I’ll move on from what I consider my base building.
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No, what I mean is that LT1, LT, and AeT are not the same thing (or are not always the same thing). We use them interchangeably (informally, like here). They are protocol, coach, and “model” dependent. Kind of like the “Zone 2” confusion after ISM went on some podcasts. We had to start saying “ISM Zone 2” (or whatever) in order to disambiguate.
Most of the time (unless I have a reason otherwise) I think of LT1 as “aerobic threshold”. And I think (someone correct me if I’m wrong) that is mostly what ppl think/say. But some of these guys have been around for a long time and use the terminology in a more historical way…or just a different way, if they are coaches.
If you use the term “aerobic threshold” to mean “the effort at which I can ride for <<30min, 60min, whatever>> with no appreciable rise in lactate (and HR)” then you can certainly make that effort start to approach CP/FTP/whatever. If you have done that, Scott Johnston would say you have “improved your AeT”.
If you use the term “aerobic threshold” to mean LT1 then yes you can make it move (with a lot of hours), but it is not the only way to improve in that area. Often LT1 will stay right where it is but the inflection of the curve after LT1 will flatten. Also, plenty of athletes (myself included) never see an increase in their HR at LT1 but their power can increase (I believe sryke is seeing this). But at the same time as seeing power increase at LT1 (with same HR), they will experience an improvement in the above scenario (higher HR + power with little/no decoupling). In that second scenario, some coaches (like Scott Johnson) would say “see, we’ve moved AeT closer to Ant”.
And I would think: “but LT1 hasn’t changed so you didn’t move it closer”. But by his definition, he has.
It’s frickin’ confusing but it’s not wrong.
Another coach might say: yeah, LT1 (inflection point) stayed where it is but you have changed the disposition of CHO and Fat contribution to the right of LT1 on the curve. Aerobic threshold (to me) hasn’t changed but you bet you saw a fitness improvement <— @WindWarrior Probably your scenario?
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Color me confused, I don’t know. All I know is that for reasonable (to me) durations at z2, z3, and z4 have almost no aerobic decoupling. So I mostly ignore decoupling, except when coming off a break.
Exactly. You are able to achieve a higher steady state (sub-threshold) w/o any appreciable decoupling. Point being: that is NOT necessarily an improvement in aerobic threshold. You’re more aerobically fit. But LT1 (inflection point definition) might have stayed exactly where it is.
without lactate testing its all speculation. I suspect my lt1 moves to the right, but won’t bother trying to explain something I’m not measuring. Using only power and HR, all I can say is that over a season my power increases at “all-day HR” (upper z2 / lower z3).
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exactly, because 50% CHO vs. 50% Fat could have (and likely did) move. That doesn’t mean LT1 did.
Also, I’m not trying to convince you to start sticking yourself to get lactate. I’m trying to say if you listen to this guy (and I think he’s worth a listen), be mindful of his definition/use of terms.
Said it before and I’ll say it again, needles make me woozy so I’m drawing the line at gas exchange. Call me scardy cat, its ok.