Zone 2 and algorithmic training guidance

[Kristopher_Dick]

What are others’ experience with this?

I’m becoming convinced that the folks creating these algorithmic training guides (Garmin Daily Suggested Workouts [DSW], Mottiv, etc) aren’t listening to the Zone 2 pundits (who many others disagree with any how).

I start de-training every time I do Zone 2 training according to the guidance of one of these systems. From my own adapted workouts, I have to conclude that it’s the overreliance on power. When you’re Power Zone 2 doesn’t reliably get you out of aerobic zone 1 (and sometimes doesn’t even get you into Z1), you’re not adding aerobic capacity. You’re not building aerobic base if you’re not working your aerobic system.

I still do the workouts, but instead of targeting Power Zone 2, I target HR Z2. I’ve also been using HR response to guide my intervals for threshold and anaerobic intervals. So, basically, I translate the intent of the DSW to workouts of my own design.

Maybe I’m just venting (I tried another one last night and the plan immediately has days on days of “base” training at power levels low enough that, from experience, I know will result in detraining.

[WindWarrior]

In 2016 I bought a bike and within first 7 months did 6 centuries.

Learned how to ride endurance BY FEEL. First ride with 10,000’ / 3048m climbing, easy all-day pace:

Kept training as usual, then 2 weeks later, 15,000’ / 4570m climbing:

a year later, a 200mile / 322km ride:

had a power meter by then, and it was an IF of 0.67. Came out of that and kept on riding, and 4 days later set some PRs.

Here is what a fancy algorithm thought:

a little conservative on AeT HR, and I still don’t understand the MSS because I was doing a lot of ~1 hour efforts around the estimated MSS (even more when I look at NP instead of average power below):

What I learned about myself, is that all it takes is:

• doing some long easy but not too easy rides
• at a steady pace, so you don’t fall too far behind faster half of the group

and you can look at charts and visually determine your all day pacing and HR and power. Without any fancy algorithms.

Thats my experience.

[Jcmiii]

Venting allowed. I get upset with all these metrics people throw around and I don’t even use them, well most of then anyway.

Since a big part of the exercise we do is to improve our aerobic base, meaning our cardiovascular systems ability to deliver oxygen and nutrients, it is of course our heart we want to target with a great deal of the exercise. I agree with you. If the heart isn’t pumping how are we doing any good?

Heart rate has always been an excellent way to measure effort on long steady rides. It’s the short ones like intensity effort when the heart rate lags where it isn’t a spot on indicator of the moment. In its place RPE, Rate of Perceived Effort, can be used effectively or a HRM of course.

There’s a recent Podcast on Fast talk I liked by Dr. David Seiler. I especially liked when he talked about having to tone down his recent paper to avoid stepping on toes to get it published. That and the low tech methods many are using.

How Much Interval Training Do We Really Need? With Dr. Stephen Seiler

There are some more recent episodes exactly what you are discussing on Zone 2 and using Perceived Exertion I am looking forward to listening to.

[WindWarrior]

Venting allowed? Ok, if you did arm cycling to improve your heart, how much is that going to improve your ability to cycle with your legs? Very little. The big part of endurance exercise is about improving metabolic function in the muscles. More mitochondria, mito with larger surface area, mito with higher respiratory capacity, more capillaries to receive and distribute oxygen, more enzymes, etc., etc.

Training by heart rate by itself is inferior. Power is better. Power and heart rate better yet. Remember the goal is primarily training muscle fibers to increase performance. Power zones allow us to better select groups of muscle fibers to train.

When is HR better? In my opinion, if you take a long break, and have well established heart rate zones, you can do some highly productive training by HR without power zone testing. The idea here is to recognize two things: a) you will be making quick gains and b) your heart rate zones are relatively fixed and don’t change much. No need to test, go out and ride to make those quick return-to-training gains. Looking at power-to-HR in this scenario, to track progress, makes a lot of sense because your power output will be improving while your HR zones aren’t changing. Do that until the easy gains (cardiovascular and metabolic) are gone. Then power based training all the way.

Except when I take a long break, my “aerobic base” improvements appear to be driven by metabolic fitness increases. Standard boring stuff like year-to-year increases in volume of hours. And metrics wise, the ever elusive movement of the lower aerobic threshold closer to upper aerobic (FTP/CP) threshold, while the aerobic ceiling (vo2max) stayed relatively constant.

Maybe your experience is different. From all I’ve read it’s primarily about training leg muscle fibers to be more “aerobic” which has more to do with training the leg muscles than with the heart. Yes, there is a secondary role in training the heart muscle.

[ss29672]

I think my biggest gripe with “Zone 2” is Zone 2 of what? 2 of 5? 2 of 6? 2 of 7? Power? Heart Rate?

It’s far too ambiguous when the intensity zone isn’t accurately described against the regime.

I think DFA Alpha shows some promise in helping determine your personal metabolic transition regions.

[MedTechCD]

You’re absolutely right that this Z2 thing is very confusing, certainly for anyone new to the matter.
The whole fuss about Low Intensity Z2 actually means ‘below AeT’, below your aerobic HR threshold which is normally very close to your LT1, first Lactate Threshold.
So for Seiler’s 3 zone system it is Zone1. In the 5 zone HR system, it is Z2. In the 7 zone Power system, it is around the border of Z2/Z3, so high Z2 to low Z3.
All this only valid if your HR and Power zones are set correctly.
Looking at it objectively, it’s a total mess

[WindWarrior]

What I think often gets left overlooked, in the race to obsessing over metrics and optimization, is that you want to do as much low-intensity volume as you can make time to do, without impacting your ability to do intervals work. How low of an intensity will depend on several factors: overall volume, off-the-bike stress, interval work, your training experience, and your ability to recover. To name a few.

Some really good Empirical Cycling podcasts. As a result I’m mostly doing easy work by RPE now.

Seriously, if you obsess over what zone2 means, go listen to Empirical Cycling podcasts on endurance or zone2.

Keep it simple, easy but not too easy, experiment and find what works for you. For example when I’m well trained, and averaging 8 hours a week, I can put down a couple 2 hour endurance sessions just above my self-assessed lower threshold. For me thats starting out around 70% ftp and ending in the 75-79% ftp range.

Theoretically I’m generating autonomic nervous system stress that adds to recovery. So what, I get tired training 7-10 hours a week during the 3 weeks of loading. What matters is how I respond over those ~8 hours/week, week after week, block after block. And can I continue to do the work? If not, lower the intensity of some/all of the endurance sessions/work.

And I don’t stress or worry about “going to low” - for me that usually means I take it a lot easier on my longer weekend ride, those are more in the 55-65% range. But if I dial it down to 50-60%. Don’t worry, just put the work in consistently, 4-5 days/week, month after month, year after year, and the magic of compounding should happen.

And regarding “junk miles” LOL, over a block or two, I can see positive impacts to adding 30 minutes of bonus work at the end of the 2 hour mid-week sessions, at so-called “junk mile” intensities of 30-50% ftp.

TL/DR: when doing endurance work, just ride your bike and eat. Increase your capacity to do work over time. Do some really hard repeats or intervals. Get faster.

[R_S1]

Thanks for sharing your experience. I mostly rely on feel and RPE for my endurance training, only using power when doing intervals or high-intensity efforts. Sometimes, I check my heart rate to make sure I’m not underestimating my RPE.

I have a question: I use a 1-10 RPE scale, and for LIT (low-intensity training), I try not to go above a 3. For me, Zone 2 would be around a 5, for example. How would you translate that into your own RPE scale or sensations? (I usually avoid factors like saddle discomfort increasing my RPE, but I’d like to know your take on it.)"

[WindWarrior]

This week I’m back on the bike after a 3 week break:

haven’t changed my ftp so those Mon/Tue/Wed efforts were maybe 65% / 63% / 68% but I don’t care that IF and TSS are off a little.

Mon and Tue were solo 1+ hour efforts, definitely a little rusty and I gave them a 3 RPE.

Wed night group ride - pulled for 30+ minutes at around 20mph, rotated off, and pulled again. Actually felt pretty strong - slowly upped efforts a couple time to chase down a few guys that rode ahead…

gave it a 4 RPE.

Versus Tuesday’s steady effort at the unchanged ftp of 250 (from June):

at the moment its probably 235-240 but based on the past my upper threshold / FTP will recover and climb back up pretty fast.

And if I change ftp to 235:

steady state 30s power is still sitting in green power zone 2. And IF went from 58% (ftp: 250) to 62% (ftp:235), and TSS went from 42 (ftp:250) to 48 (ftp:235). But no changes to HR and no changes to RPE. I’m sure the small distortion in my CTL/PMC will survive the indignity while my fitness catches up to where it was in the nearby past.

[Kristopher_Dick]

I’m tempted to doubt the mitochondrial theory of zone 2, in part because of this video from GCN. I also reject the pure power based Z2 because of the testing required to establish the “right” zone 2 in this GCN video and this video, following which it was suggested that Z2 would be of little benefit after Manon’s initial training cycle. Again, my own experience suggests that it’s some minimally informed geek in an office (software engineer by trade myself) defining the Z2 for “base” workouts. This is the crux of my displeasure: following the algorithmic workout guides results in detraining for me, while following the intent of the suggested workouts with closed loop training data increases my abilities. There’s clearly something significant missing from the algorithms (haven’t tried them all, too broke to do so right now).

[Kristopher_Dick]

Also, I’m not relying solely on GCN. They have their flaws, too, but it’s accessible content that I can find easily to illustrate the point.

[WindWarrior]

I’m not sure what you are rejecting. Zones are a coaching artifact, and reflect well established motor unit recruitment patterns.

Given all we know, I don’t understand why anyone would do only zone 2 training.

Manon was detrained. Riding easy for 6 weeks will produce gains. She maxed out at a 9 hour week. For “zone 2 only” training that is not enough and likely going to cause her to plateau. Because zone 2 only. Again, why would anyone do ONLY zone 2 training? Did anyone listen to San Milan? He didn’t say “train in zone 2 ONLY.”

Back to all we know… recall the elites and pros of old would do long slow distance training. But they would progress that out to 20-30 hours a week in order to get the fitness gains.

It’s a tradeoff of time and intensity.

HR was only preferred because she was untrained, they expected fitness improvements during the 6 weeks, and HR zones are relative fixed. So using HR made sure this experiment was conducted at the top of zone2. Because her top of zone 2 power was increasing - 20W in 6 weeks. When I’m training all year, with only a few short 1 week breaks, my ftp and zone2 are really stable and no reason to get hung up on heart rate.

One problem with Manon’s 6 weeks - “zone 2 ONLY” will primarily recruit and train Type I slow oxidative motor units. What about the fast oxidative motor units? Why wouldn’t you want to train those too?

My only other comment, as this is getting long, is that HRV and the autonomic nervous system recover quickly when training at low intensities. Likely somewhere in zone1/zone2. So when you start pushing 20 hours a week, recovery can be a big deal.

Food for thought. I’m not trying to sell you on zone 2 training. All zones have a place in the training mix.

[Luisma_Gallego_Soy_P]

I don’t think GCN is a more reliable source than Dr. San Millán’s research, I’m surprised to read that and I’m surprised to read that since it’s what we have more access to we pay more attention to it. I haven’t heard anyone say that you only have to train zone 2. These world top trainers work with elite athletes and the levels of improvement are difficult to achieve. An amateur needs to develop the oxidative pathway and one way to achieve this (it is not the only way) is to work in zone 2, I think there is enough evidence to see the improvements that exist in an amateur working in this zone. You can try it, train an amateur athlete with basic level and start with high intensity, overtraining and stagnation will not be long in coming.

And referring to the algorithms that some have criticised, algorithms are algorithms and they have to be interpreted with the athlete’s history and not just a number, they are only used as a possible guide and starting from a base point.

Another comment I have read is that it is a mistake to use only watts, I doubt that there are many coaches who use only watts and do not use heart rate as a guide, unless they use these AIs that prewrite by watts and analyse by watts. No trainer uses only watts and when they analyse a workout they do so with all the internal and external load variables that are currently available.

[WindWarrior]

I think there is some misinterpretation of GCN videos. Watched them when they came out. They are well done, and the EXPERIMENT was zone2 only. Not because of San Millan, but because thats what GCN decided to do. And that led to people misinterpreting it as a recommendation. It was an experiment.

Been building models and algorithms for 40 years, completely agree that most people don’t take time to understand the model’s domain of validity, assumptions, and boundary conditions. And frankly, most model developers don’t do a good job explaining.

@Luisma_Gallego_Soy_P

An amateur needs to develop the oxidative pathway and one way to achieve this (it is not the only way) is to work in zone 2, I think there is enough evidence to see the improvements that exist in an amateur working in this zone. You can try it, train an amateur athlete with basic level and start with high intensity, overtraining and stagnation will not be long in coming.

Yes, I tried it. A long period of mostly fairly high-intensity training during my self-coached 2nd season:

7 months of that, from November to May.

Almost all high IF (>=0.9) and a little over 7 hours/week average. Polarized (HR) it was 32% / 52% / 16% in 3 zone system.

Listened to my body and took time off when needed. By early April my TTE was over 1 hour at 3W/kg and 275W ftp. Didn’t stagnate, kept getting faster until I started my traditional off-season in June/July/August when it gets really really hot.

My algorithm - a lot of 30-90 second all-out efforts, and a lot of longer and longer threshold/SS work. Rinse and repeat.

I’ve heard various pundits speculate I should have burned out. But it didn’t happen. Listened to my body and did a lot of 2-a-days with a shorter 20-30 minute morning ride near 1.0 IF and a longer afternoon ride at sweet spot / threshold (mostly IF >= 0.9). Some might be surprised how much quality threshold and above threshold work you can do with 2-a-days like that. And I was fifty-five at the time, with a stressful job and family life.

Then 6 years later with guidance from a coach, achieved nearly the same fitness by mostly riding endurance plus interval/repeat work:

But 8.75 hours/week endurance first training, vs 7 hours/week high-intensity training. So 1.75 hours/week more to achieve similar fitness. Polarized (HR) it was 68% / 29% / 3% in 3 zone system.

Primary motivation for doing that - health vs performance. And it worked, my RHR dropped 10bpm, HRV improved to normal levels, etc. High stress job and suspect my body was perpetually locked into fight mode between the job and family and high-intensity riding.

My point is - experiment! There is more than one way to develop a strong aerobic metabolism. Learn to make wise tradeoffs between volume and intensity and density and recovery.

[Guillaume_dubois]

For my part, I consider that to have sufficient stress in Z2, you have to ride for a long time, in one go. When I observe a cardiac drift on my session, I tell myself that I have done enough for it to be a good session. The problem is that it is very long, and difficult to fit into my schedule

[Jcmiii]

@R_S1

I have a question: I use a 1-10 RPE scale, and for LIT (low-intensity training), I try not to go above a 3. For me, Zone 2 would be around a 5, for example. How would you translate that into your own RPE scale or sensations?

Some identify Zone 2 with a breath test or the ability to hold a conversation. I like that better than RPE which is open to a lot of interpretation.

I find RPE helpful for high intensity intervals because identifying hard VO2 efforts seems straight forward. Zone 2 is different. Going by feel, my Zone 2 is an RPE of 3, a level I can maintain all day. But some would say that is an RPE of 5 and the definition of an Endurance level, but I interpret 5 as a Tempo level I can maintain for merely hours. Using a power meter, cheating I know, I can say that using RPE there is a lot of overlap between Zones. As i get warmed up, using RPE I experience power creep and when my heart rate catches up I am beyond Zone 2.

This is what Zone 2 training looks like | Peter Attia

The breathing test or the ability to hold a conversation seems the best way of identifying Zone 2 in my experience. I have used that to customize my Zone 2 limits on my charts. (That YouTuber has some other good conversations with expert trainers on the subject of Zone 2 you might find interesting.). If you were holding a conversation with someone on a phone, you would be speaking clearly while the person on the other end would certainly know you are exercising. They would likely be able to hear you breathing and you would likely be taking breaths in the middle of sentences where you normally wouldn’t. That is the upper limit of Zone 2. In the GCN video mentioned earlier the GCN person is holding a conversation in Zone 2 while riding down the road. Another good example. We would know with no video that she exercising and she can hold a perfectly normal conversation.

Some measure Zone 2 by the ability to continue breathing through the nose while exercising.

In the end it isn’t as critical as you might have been led to believe. The prescription of Zone 2 is to allow many hours of riding per week without the need for much recovery. You aren’t getting anything you aren’t getting in other Zones unless you are putting in those large numbers of hours which you simply can’t put in at higher intensities.

[fabric5000]

@WindWarrior

Some really good Empirical Cycling podcasts. As a result I’m mostly doing easy work by RPE now.

Seriously, if you obsess over what zone2 means, go listen to Empirical Cycling podcasts on endurance or zone2.

This. Go listen to Kollie Moore at Empirical Cycling. How hard is a Zone 2 ride? “Go for a walk on your bike.”

You know how we all look at the pros? The guys who have an FTP of 400+? They are doing their Z2 in the low 200s. That’s that 50-60% that @WindWarrior is talking about here.

Almost everybody is doing their Z2 rides too hard. The pros are fast because they ride at 50% for 20+ hours a week. You can only compensate so much for not having that much time by riding harder before you start to get too fatigued.

Yeah, it sucks, but the only way to get really good is volume over time. And the only way to get more volume is to dial it back so you can do…more volume.