Zone 2 training with Iñigo San Millán, part 2

Yeah it’s gotten lost somewhere along the way :man_shrugging:

I get what you’re saying and have tried to make the same/similar point on a few occasions the last two or so years.

As much as ppl bemoan the repetitive nature of the other two threads on this training approach (of which I was an unapologetic contributor), at least we got the concept right. Or close enough.

Nuance and things named the same thing fail on the web.

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Is it the easier rides or the body is finally adapting to increased volume? Maybe (probably) a little of both?

With training it’s often not “this works and that doesn’t” but more one thing that builds on another. For example, I spent a couple years doing double days through college and after chasing the marathon standard. I saw a big boost once I shifted training from doubles to longer singles (i.e. instead of 30/60 just doing 75-80 min). I don’t think it was that the singles were superior to doubles but rather the doubles laid the foundation.

It’s all connected… but all that said being able to recover is huge and glad to se you find what you need to do to improve!


You’re only supporting my point. If you calibrate your power zones to the physiological zones, you will be comparing apples to apples when using zone descriptions when different people have different power duration curves.

In a 5 zone physiological model (the original model) lt1 is z2 for everyone.

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That’s not the case for everyone as explained previously.

I can use my own lactate testing as anecdotal example where my LT2 was at around 315 watts and LT1 was at around 295. That is clearly not a zone 2 in classical 5 zones model.

I guess one of the main differences is that 5 zone model is FTP based while lactate based models are based of at least two values - LT1 and LT2. One cannot accurately guess LT1 just from LT2 (which in this context can be replaced with FTP) as there will be huge individual variences depending on training history, muscle fiber makeup, potentially dietary habbits and so on. 3 zones model on the other hand is based on lactate thresholds, hence there we can state with certainty, that Z1 is below LT1, Z2 is above LT1 and under LT2 and Z3 is above LT2.

To come back to original idea - Z2 in the context of how ISM uses it, I agree it is at/around LT1. Although, I am not sure if we have had clear communication from him whether it’s preferably very slightly below or at LT1 (which, frankly, is a range itself, there is not a tipping point of 1 watt value) or at/slightly over, or depends.

To add, if I were to set my 5 zones model based on my lactate values, it would be boundary between Z2 and Z3 where LT1 would be used. Z2 by definition is endurance zone and it will not be much of long or endurance ride when your LT1 is well developed. The caloric and mechanical requirements for higher level athletes are significant. Doing few intervals of say 20 or 30 minutes at around/slightly below LT1 is a solid workout itself. Although, for low volume, aerobically ver undertrained person it might be quite a bit different, I would still be hesitant to use LT1 as a separator between Z1 and Z2. I am interested to hear reasoning counterwise.


Im not sure where the disconnect is coming from, but we (you, kurt, me) actually agree on what an ideal distribution should be. Im merely saying that you should adjust your power zones to match your physiological zones. The 5 zone model predates power meters when it was set through lactate or hr values. Coggan’s zones are based on an assumption that lt1 is 75% of lt2. Im saying if you know lt1, you should adjust your power zones with that knowledge.

That way, z2 means the same thing between individuals. And in the context of this thread, ism uses z2 as an intensity zone, that is not where one should do the bulk of their training. In order to reduce metabolic strain, training below lt1 is the key to maximizing volume while being able to hit your other key workouts. In the 5 zone model that is z1.

From reading this thread, it looks very confusing to be suggesting z2 in training while that zone in the context some people are using might be something very different than the zone this thread was created to discuss. I’m merely suggesting that we would get further if we speak the same language.

When i first started training nobody had power meters, and zone 2 meant lt1 or vt1 as it was the point where things started getting harder and respiration started to increase. Back in the day, the prescription for z2 was 20-30 minute intervals in friel’s training bibles.

Why does almost every training platform allow one to customize the boundaries of their training zones? Make sense to utilize that option if you can estimate lt1.


Not sure where to put this but I know @stino77 has been updating their z2 progress with a z2 focused/ ISM approach so thought I would share having tried to adopt some various things in this and other similar threads.

z2, LT1, VT1, ISM or otherwise aside, having just completed by base block with a “z2” focus if I ever needed evidence that volume works (or at least I respond to it) I have it…

I did 7 weeks of z2 focus with a weekly Zwift ZRL race for the first 5 weeks, a couple of 3x20 SST @ 90% when time was tight and whatever a group ride threw at me when the weather allowed.

About 80% of time was z2 (mix between 65-72%) with no ride shorter than 2h with most w/o’s 2.5h, 3h or 4h where possible. Worked out about 100+ hours of base (15, 12, 15, 15, 15, 17, 20hr wks).

During the block I observed that I gain about 20w+ for the same HR and compared to the same period last year above, 10-15w up overall across the 65-75% MaxHR range. Efficiency increased and decoupling stayed at <3% avg despite increasing ride duration. NP across the rides evened out also. I was particularly pleased with only circa 2hr of coasting in this block.

Having now taken a couple of days easy riding to RPE etc as part of recovery week and then re-tested (using KM Baseline Progression as I always do) ahead of my next planned block…the results of which I was completely surprised with…

Having not not done any threshold work really (at least no consistent TiZ) for nearly 3 months (prior to this 7 wk block I had a week off as “off season” and prior to that had just completed hill climb season so was vo2 max focused), the outcome was only being down 4w and 10mins from my peak TTE last season…I can only put this down to increase in volume minimising and loss of gains from last year.

Was I working at optimal % of z2, or LT1 or where ISM suggests, who knows…but in all honesty I can say the recent quote from Kolie Moore certainly worked in my case… “have a snack and ride your bike”.

I was going to do a SST block, but this has changed things.

Back to the thread in hand though, its extremely valuable :smiley:


Super post! Top :wink:.
I am only in my 5th week now so a little too soon to make my conclusions ;-). I Will keep it posted it here.

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Who’s 5 Zone model there are a few?

You could equally say, depends on the model…

Z1 and Z2 below LT1
Z2/Z3 edge to low Z3 at LT1

As LT1 varies dramatically as a precentage of threshold between individuals, for some off the couch it might be in Zone 1, for others well trained it could well be in zone 3.

I’d suggest to match in a physiological sense they would need to be heavily individualised if the zone model is based off threshold, so while it might be the intent it will mean something very different to each individual if thinking about a precentage of threshold.

Easier to to say, well maybe not easier but clearer to say…

Below LT1
At LT1
At LT2
Above LT2 etc
Coggan Z2

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There are comments referring to Coggans Z2 (7) and ISM Z2 in the same thread, yes its a ISM thread but it is an assumption that Z2 means ISM Z2 unless defined.

If talking to face to face you can clarify in seconds, not so easy on a forum without very clear communication.


Yes, the whole point of what i was suggesting is that our physiology is different… so why not use terms that mean the same thing metabolically between individuals. That those points happen at different percentages of threshold is precisely the reason. Staying below lt1 should mean something different than riding at/ around or above it but might all fit in z2 if using the arbitrary percentage of ftp approach.

If a model’s zones mean a different metabolic state for different people it is a rather weak model. I don’t see this as any different than adjusting your percentage of map from the ramp test based on your own individual power profile. While a population average might be 75%, that doesn’t mean that it is ideal for you. Same with your power zones, those are approximations based on a population average and a fair starting point for most people.

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I have a few TL;DR questions …

…or maybe they are TC;DU question? (Too confusing; didn’t understand — did I just invent a new internet acronym??!!?)

  1. Would it be fair to assume, or at least fair to put into practice, that the minimum-effective-dose for a Z2 training model is 2hrs per trainer session and 10 hours per week?
    —— I’ve often believed that the biggest misunderstanding about doing 80% of your training in Z2, or below LT1, is that there is a minimum volume requirement. I don’t believe someone training 3 days and/or 3-5 hours per week is best served by this model.

  2. I am currently in a bit of a training “purgatory” in that I am recovering from back-to-back illnesses (flu, sinus infection) that kept me off the bike for almost the entire month of December. As such, my pre-thanksgiving FTP of 295-300 is now at a TR AI-detected value of 278 (my first week of workouts more-or-less confirmed this is an accurate number). With that said, I believe the quickest way to regain my fitness is by doing A LOT of Z2 work which will allow me to increase my time on the trainer (which I have time for) without burying me in fatigue and over-training. However, all of my power-to-HR values are skewed from what I normally see … so my question is: assuming that I’m doing a minimum session of 2 hours on the trainer for Z2 rides, would it be best to manage my efforts - for minimal metabolic cost - by HR? And if so, what would that HR % be? I have been using 80% of max HR as my ceiling for Z2, regardless of what that relates to in % of FTP

  3. Given a 10-hour training week, I wonder what you would “prescribe” as an optimal load for an 8-week block.

For reference, I am 48 year old male with over 5+ years of structured training in my history. I train Tue/Wed/Thu/Sat/Sun with Mon/Fri as rest or non-bike active recovery days.

Today (Sunday) marks the end of first full week of returning to training. My schedule this weeks has been as follows

Monday: off
Tuesday: 2hrs; 4x12 SS @ 90% FTP + Z2
Wednesday: 2hrs; Z2
Thursday: 90 mins; 2x20 SS @ 90% + Z2
Friday: off
Saturday: 2hrs; Z2 w/4 20s sprints
Sunday: 3hrs; Z2

Total: 10.5 hours

Would welcome input.

  1. You might be surprised. But more volume is almost always better, and I think it’s fair to say someone riding 3-5hrs per week is going to need more intensity as a % of total ride time than someone doing 10+.

  2. 80% of max HR is pretty high for endurance paced riding. You mention that your longest ride is 3hrs or so, and you can probably get away with riding that high for that period. That doesn’t mean it’s optimal.

FWIW, for newer athletes who don’t have a well dialed sense of RPE, and indeed for myself with a major volume increase, I ride and prescribe more in the neighborhood of 65-70%. I use 75% as a proxy for LT1 in the absence of other information (talk test, VT1, lactate testing). For me (n=1), it’s pretty bang on.

As I mentioned above, I was doing a lot of my endurance time in that range of 70-75 or slightly more of maxHR, and it was affecting my ability to go hard. I’ve dialed it back now to where I am riding multiple 3-4+ hours rides per week between 65-70% of maxHR, around 50-55% of FTP, and I’m seeing a performance increase on my interval sets and not dreading riding my bike.

My hope is that over time the power comes up, but I’m not really worried about it at all anymore.

I’d recommend you base your all day endurance pace somewhere in that 65-70% range, then spend your couple of hours up around 75%/LT1 and see how your interval sessions improve.

  1. Nothing wrong with your plan for now. I’d try and get an extra day between the interval sets, but at durations that short (for SST), it’s probably not a big deal. Get up over 60-75 minutes of SST, and drop back to 1x per week and then do some extensive tempo in place of the second SST set. That’s worked well for me, and some of my athletes too as well as anecdotally from others on the forum here.
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This is the plan, and I should’ve mentioned that.

Like I said, I’m in this rebuild purgatory from illness, so trying to navigate that … I’m respecting my new capacity while also understanding that I was capable of so much more about 45 days ago, and getting from ~280 FTP back to ~300 shouldn’t be as heavy of a lift as someone trying to do it the first time, or even someone trying to regain form after an extended period (i.e. like 6+ months off). Maybe that logic is flawed, but that’s how I’m thinking about it.

Appreciate the input overall - really helpful :+1:

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Personally, I don’t think 10 hours / 2 hours at a time is anywhere near a minimum. Most recreational cyclists don’t even ride 10 hours per week.

Anecdotally, I maintained my fitness last fall by doing one hour per day Z2 on the trainer. I started my tempo based build in January and hit my best numbers ever in June.

Maybe Kurt could chime in but isn’t ok to let FTP wane a little in the off season while maintaining aerobic fitness with low stress base riding before you do a build cycle again?


Couple things:

I think there is a difference between maintaining fitness vs. building a base. I was speaking about the latter.

I think z2 ride less than 2 hours definitely help maintain fitness.

Apologies if it’s already been mentioned but enjoyed listening to this on the turbo this morning.


For sure it is. Shedding long term fatigue is important, and you’re probably going to lose FTP when you do that. I take two weeks off the bike every year. Last year, I took four because I got hurt. FTP was 285 or so when I got injured. Came back the first week and sat at 255 for an hour.

I was back to 280 pretty quickly. I have seen most of my athletes take their breaks and then regain their fitness within a couple of months. Pushing higher is the part that takes the real effort.

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I am not a huge proponent of spending several months just noodling around in the little ring. I like a little bit of intensity when doing volume unless I’m really trying to push volume higher. That could be a short threshold session. That could be a Zwift race or something. But once the volume is where I want it, push into extensive SST/threshold/tempo. That’s my typical “base” approach.

Keep in mind that most of my athletes are in the 8-12hr/wk range. As I’ve mentioned, with more volume, intensity necessarily gets dialed back until you can handle the volume.


I’ve actually just taken 6 months off the bike. I’ve been running a little, lifting weights (not heavy), snowshoeing, cross country skiing, and lately indoor rowing to stay fit.

It will be interesting to see my numbers when I get back on the bike (very soon).

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Anecdotally, I tend to agree with @kurt.braeckel here. I’m not disputing that ISM might be saying some of his athletes have seen good results doing their endurance work right around LT1, but I’ve found as a practical matter, that wears me out for the intensity days (in something like an 80/20 model).

I’m going to put it to the test this year and see if I can success the intense workouts in the TR POL plan, while also hitting their relatively high endurance ride power targets.

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