How to test AeT efficiency

Hello,
I’ve read the “the cyclist training bible” from Joe Friel and I’m now interested on keep monitored my AeT efficiency.
The test that Friel recommends is basically to ride at the AeT for 1-2-3 hours and see how the output power compares over time. If Power/HR increases it means that AeT efficiency/capacity is improving.

In my case I’ve already made a laboratory test in a training center (with the mask while riding) and my thresholds are:
VT1: 146bpm - load 155W - O2 23,2 ml/min/kg - RER 0,84
VT2: 171bpm - load 260W - O2 40,3 ml/min/kg - RER 0,99
VT3: 181bpm - load 305W - O2 48,1 ml/min/kg - RER 1,05

My CFmax was 184bpm.

I’ve created a workout, where after some warmup I ride for 2x30 min at 140bpm (this way I can also calculate HR decoupling (drift?) of the fist half/second half: Are You Fit? All About Aerobic Endurance and Decoupling)

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I’m not sure that riding with HR target 140bpm is correct, and staying exactly at 146bpm seems even worser. It seems very high to me, with a quite big effort (135 seems reasonable to me). I’ve read somewhere that the test should be made at 10-15 bpm under VT1. In other places they recommend to stay at VT1.
Doing the test the other way around by fixing the watt (eg 160W) seems not very comparable over time when my FTP will (hopefully) increase. I’ve read that HR zones are quite fixed, while Power zones not.

What is your recommendation/opinion?

I’m interested at comparing AvgPower/AvgHR over time.

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Nice question. I don’t know much about lab testing for AeT or how those O2 values exactly relate. I do know VT1 should be the same as AeT but to me 146bpm seems very high with a max HR around 184. People are different. I do think the accepted belief is below AeT should feel very easy and sustainable for many hours with no problem for any trained cyclist…

I could ask Andrea about the specifics of these numbers as he has been mask testing cyclists for 30 years… but I from my perspective that is not necessary.

If you read Maffetone, he has been focused on AeT for a very long time and his area of expertise. More so than Joe, although I respect Joe and the cycling training bible a lot. Anyway. Maffetone’s aerobic test is much simpler to execute.

Converting his from running to cycling I would say. Use standardized warmup protocol that slowly brings your HR up over 12-15 minutes to your target. Then hold your HR in a tight range using consistent breathing patterns and minimize pre-ride eating as it affects your HR a lot. Then at 20 minutes compare your power in 5 minute increments. So 20-25,25-30, 30-35, 35-40… And just do that once a week for example and watch the pattern to compare previous weeks and your power should go up for all of them but some times you will only see increments of one of those.

Maffetone believes their is almost no risk by going to low of target, but going to high can stall progress. Many of his followers have experienced the same, myself included. So if it was me I would likely start around 130bpm… or a value that your breadth does not really change from doing nothing. Maybe a slight change, but more like walking… Conversation is just like going on a walk. If you do this test weekly in 2-3 weeks you should see improvement if your training is truly causing aerobic improvements.

I did this process but did the opposite, going with my wife that I started running at 135bpm and after 100 days in a row I had an occasional good day that I could go the same slow pace at 95bpm…

I think most of the cycling community regarding setting “Zone 2” talk about an HR target that is too high.

For me my max HR was the same as yours and I did lots of tests including Moxy, like muscle oxygen, and I could see my LT1 deflection point was clearly at my Maffetone value which was about 130bpm at that time. These days I shoot for below 125.

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So one problem with your warmup protocol is you move yourself out of predominately fat burning to carb burning with the higher intensities. This defeats some of that clarity in aerobic efficiency… but mostly Maffetone does this as a training focus of keeping you fat burning which also ideally includes fasted training.

This HR/power ratio is so easily affected by pre-ride activities. HR, especially below AeT is very sensitive (how you breath can change it by 5-10bpm, just taking hands off the bars…)… so to see clear results requires very consistent processes and gentle handling of this testing process.

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Ehi Alex, thank you for your extended elaboration! I appreciate a lot.

As said, I also think that 146 is very high, but this is what came out of the test. In theory it’s the level where the lactate increase of 1ml from the steady level of 1 to 2. I also would do the test at a lower level, for me 135bpm is safe and in any case can’t screw the output too much. 140/145 is very demanding.

I’ll do the test tomorrow morning with my HT (and after that I’ll do my SFR session from CJ plan)
I’ll read Maffetone too, in the meantime do you have some link to share where I can read something more about it?

ah, last but not least: you’re right about the warm-up, probably it’s not good like that. It was a my idea to push the HR a bit high and avoid to stay at very low HR for a long.

How does the HR target work in your app? doesn’t it increase the intensity of the HomeTrainer until the HR is in target? in such case at a certain point I think it will start using carbs to increase it quickly. Could you please elaborate a bit how it works? perhaps I can remove that initial part like this?

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The second 10’ interval is to arrive at HR target. I might also split the 2x30’ main intervals (used to calculate decoupling) in 12x5’, but I’m not sure that the power on those intervals would change a lot, the effort expected is quite low, and the power output I expect is quite steady.

Tnx again :slight_smile:

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Yours is fine but I would actually enter 5 minute intervals, then it is very easy to compare. Like below

I am on vacation and heading out skiing now so will respond more later.

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Ok, I’ll shift to 12 x 5’ minutes interval. Just a little bit more work/math to later calculate the average on two blocks of 30 minutes - but not a big deal :slight_smile:
Enjoy your skiing, talk to you later!

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This is a very nice discussion. I completely agree with everything Alex has said.

You need to remember that though the threshold was tested on that particular day at 146, this does not mean that this is the number you should be crunching on all of your aerobic efforts or tests.

As it is a threshold and your body is not in the same shape every day or week, one day, you’ll be under the threshold at 146, and the next day, you’ll be over the threshold at that same 146.

It only indicates that training needs to be done well below 146. However, if your Threshold is already 146, you have a good aerobic base. Keep that up.

You did a great job lowering the intensity of that warm-up. Going slow is really the key here.

Have fun, Coach Robert

Yes, I have experienced as Joe suggests that if I have a strong aerobic base and I am 100% below AeT. I have 0% decoupling. Maffetone suggest something similar, so yes keeping it for an 1:20 you should be able see this. Which tells you two things. Is your target too high and do you have a good base. Each person is a bit different so I would never assume everyone is exactly the same but it’s just a very good indicator. So if you wanted to do 2 long intervals after the 5 x 5’ intervals they you could easily just in TrainerDay compare the first long one to the second long one average power and see if there is any decoupling but any of the analysis apps will also show this.

Maffetone’s big book is good. Most of his books have the same core information. You can just search Maffetone 180 or ask chatGPT to understand his test.

I was going to say the exact same thing.
If the lab test was done correctly and the measuring devices were calibrated, the test results should be trusted. VT1 sits at an RER of ~0.80 and VT2 at RER=1. And RER (respiratory exchange rate = respiratory quotient = VCO2/VO2) is much more reliable then lactate testing (if the MET cart is functioning correctly).
But I am surprised that an LT1 at 146 comes out with a HRmax at 184. Or is this 184, the max during the test and not your true max HR?
Elite riders can have a VT1 that is very close to VT2 (only about 10-15bpm separate), but that is the result of many years of consistent training and a volume that you can only get to if you are a pro. If you are in that case, training at VT1 is clearly hard work. Your cardiovascular system has been trained to achieve that result, but the strain on the muscle system is high at such an output.
If you want AeT efficiency, and decoupling calculated for you, use Intervals.icu. It has those parameters by default analysed.
The Power/HR quotient is something you can use for the entire aerobic zone as a ‘sub-max’ test. It allows to follow up progress without doing an all out FTP test. Check decoupling for the duration of the events you’re targeting. If you have significant decoupling after 2 hours, you’re not ready to go ride a Grand Fondo of 5-6 hours. Check both efficiency and decoupling at different intensities below VT2.

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Thank you @Robert_UCL and @Alex - I really appreciate your feedbacks.

I’ll do the test tomorrow early morning (wake-up at 04:15 am to finish by 7am and bring kids at school :))

I’ll do the test like this:
image

I’ve verified from past the last workout that my bpm is normally quite low until I start going above 70% FTP. Last Saturday it was 130bpm at 78% ftp (over 5 minutes after 15 minutes warm-up)

After the AeT I’ll do my next workout from CJ (I’ll just skip first cooldown and second warmup to stay in more or less 2 hours):

I’ll share the results, perhaps a nice discussion to elaborate the results will start.

Probably this weekend I’ll do another FTP test after the first 2 months of training.

Thank you again!

do you think it’s ok to do the test without breakfast and just an espresso coffee? Coffee might impact HR a bit, but I take 6-7 per day, so it’s part of my regular schedule.
Probably better to don’t ingest carbs or other things. For me it’s fine to do like that for all AeT tests (and in the end it’s better to avoid sugars around, to give a stronger signal to the body to use fat, despite 80’ test is really short)

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It’s sounding like you have a very good aerobic base 5-time Ironman winner Mark Allen followed low hr training and when his base was very strong he would do intervals at AeT because it was not easy.

I experienced this to some degree as well about 12 years ago. Would love to hear your test results but if you have a very optimized aerobic system you may not see a ton of progress. Although if you read and follow Maffetone you might see improvement but usually better to start late fall.

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SFR #7 :heart: enjoy.

I’m also very curious :slight_smile:
do you have time to explain a bit how the HR mode works in the app? My assumption is that, in a loop, it increases HT resistence by few points and wait something like 30 seconds to see the delayed effects on the HR - is it more or less like that?
If it’s like that I expect to arrive in Z3/Z4 before seeing my HR at 135, and after that it will lower the resistence. Never used such mode, just guessing

Moreover if I set hr target in a shorter interval it will increase the HT resistence more aggressively/quickly, right?

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Yes basically as you describe but for many people to when the get on the bike and just have 135 set for example it takes about 10 minutes to get them to 135 so it is pretty slow… It changes a small amount every 30 seconds… I don’t remember the exact rules but that is the concept. But what it does it take your previous 30 seconds power level and adjust from there so if you do ERG warmup, you can get your HR to build up faster and then it will just start from the last ERG power… So in reality you could just click on quick start and click on HR+ and set to 135… you don’t even need a workout. It should remember this 135 but right now that when you restart the app it forgets but we will fix that soon.

But no short intervals it will not more aggressively increase, it is always slow so ERG is the way to get it to move faster.

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ok clear; tnx. I thought it was more or less like that, for this reason I put an initial interval in erg mode.

Maybe it’s an idea/suggestion to take into account the interval duration and the distance from the current HR to the target HR and increase the resistence slower/faster - basically calculating a gradient :slight_smile:

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Yes and soon it will put you target watts at 1200w to get your hr up 40 bpm in 5 minutes… :slight_smile: no I prefer the safe route and let users do their own custom erg ramps.

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Hello AeT test made!

As promised here the the results:

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I would be very happy to receive your comments! from the results shown it seems that the target HR (135 bpm) was fine, what do you think?

Any comment are welcome! :slight_smile:

ps this is what I see in Intervals.icu

and OT, @Alex this is the SFR workout made right after the AeT test

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Good job. I know Joe Friel suggests < 5% decoupling is good. I am not sure how much heat is affecting you, because if you are heating up I would also consider this good.

If do happen to be well ventilated, at a reasonably low temperature, I think either you have room for aerobic improvement or you also could try the same test with 130bpm and see what happens.

What was your breathing like? How easy did it feel compared to going on a walk? If you were really following Maffetone’s suggestions then it feels too easy for most people when they start doing efforts like this. Also focus on deep breadths and you will see your power go up… but most important from test to test is consistency. So just from a test perspective to compare to the future this seems good.

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Thank you @Alex !
yes, <5% is good (source)
Heat was ok, temperatura in the room with HT is 15°. I forgot to switch on the second fan, I did at the start of the third segment, and you see that power went up.

I’ve drunk water every 2 intervals (every 10 minutes)

The breathing was not like walking, it was ok, I surely was able to talk, but surely not like resting / easy walking. It was harder to keep 180w steady on the HT, the thing I dislike is that you never rest/pause/coast like on a real bike :slight_smile:
But it was ok.

Yes, I focused on deep breadths, and tried to be constand with rpm (but not a perfect job with rpm). I did the test without breakfast, and I also forgot my espresso :confused:

I think that at 130bpm is not taxing enough, and the stimolous is not very good (in terms of training). But this is still unknown territory for me. In terms of power it was low-Z3 for me.

How to understand/decide if it’s better to ride at lower/higher bpm to train aerobic endurance? The decoupling was good, so surely it was exclusively aerobic work. Right?

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