Aerobic Base Endurance. Importance of Zone 2

I have been following the traditional base plan since the start of the year in an effort to really develop some lower end efficiency and type 1 muscle strength.

The decision came off the back of my previous season and the type of rider I became.
Basically after following a medium plan for SSB, Sustained Power Build and Century plan, I became great at riding at tempo and threshold pretty much most of the time and I cracked in September.
I personally believe that there are plans with far too much intensity in them. For example if I follow a medium plan I am riding hard 4 out of 5 days. But that is another discussion…

I have been able to adapt to riding the 2hr plus endurance rides 3-4 times a week with no break and not many calories. I am aware that I am probably not improving my FTP riding in this way but I have done a lot of research on the importance and benefits of zone 2 training for the endurance cyclist and am liking the results. Less reliance on incoming sugar and calories.

I am used to normally testing every 4-6 weeks to see where I am at, but with this style of training my threshold power may not have gone anywhere or even regressed. I am really liking this approach at this stage of the season. My question is how can you grow the aerobic engine further? Basically doing the same 2hrs at a higher wattage. After all that is what we are all searching for riding endurance at 250 watts.


As I understand it in my case, more LSD (long slow distance) will improve the aerobic engine.
I work with a coach and after doing a LT and VO2max test recently, he’s having me do more low intensity riding to improve my aerobic ability.
My ftp is the same as it was in 2018 :laughing:

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We’ve been discussing this topic extensively in the 80/20 polarized topic and the more recent ‘sweet spot or sour spot’ topic.

I do think people can get tripped up in their training. It should be dose and response but people don’t wait for the response. They don’t like to rest.

If you do a lot of Z2 you can ride more frequently with less rest. If you do a lot of SST and threshold then you definitely need to have rest days - probably 3 full days off per week. I have a feeling that people short cut that and also ride outside.

People also get into the more is better mentality. If 2x20 SST if great, then doing it twice a week is even better, and three times a week is even better, etc.

And then age factors in… I’m 53 and need more rest than a youngster. I cooked myself doing base miles and then needed a full rest week. I progressed from 6 hours to 13 hours over 7 weeks. Last week was a 6 hour easy week. In the end it was probably great for my aerobic fitness but I was really dragging towards the end. I’m coming around to thinking about shorter blocks, more rest and more adaptation.


Did I correctly understand that you are simply doing a 2 hour endurance ride 3-4 times a week? That sounds like you’ve been repeating week3 of traditional base 1 mid-volume for a month now.

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You need to stress the system to get better. That stress will come through time or intensity (or both). With Z2, you need time, lots of time. If you only doing 2hr rides, thats likely not enough time. Why don’t you add in a hard SS/threshold/Vo2 ride once/twice a week (basically look at the polarized threads)? It sounds like you have a solid base level of fitness to do more hard stuff. You could also do a mini Vo2 block or threshold block to give yourself a quick boost. There are some threads around on that too. It all depends on your goals.

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You improve by incrementally increasing stress and then adapting to that. You can certainly improve by riding 3-4 days per week for 2 hrs in zone 2 if that is a stress to your system. Based on your history, that is unlikely to be the case. Now, ride 3 days per week for 2 hours and make the weekend ride a 4-5hr zone 2 ride, and I’d bet your aerobic capacity will grow (and probably your FTP along with it).

But my guess right now would be not enough stress will lead to no improvement. If you trained SST at Mid volume last season and you go traditional base MV this season, odds are good you won’t make gains. Perhaps TB HV would work.

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Progressive overload as others mention. Look at your PD curve for whatever duration you want to target and note the power. Ride at that power for a little longer. Or increase power for the same duration. Or both. As much as you can handle. Start endurance rides easier (watts and RPE) and end with more.

my thought exactly… I want to go 250 watts for a couple hours and never see my HR above 130… LOL

Mine is the same as it was in 2016… such a long god damn plateau… >.<

when you say that, you are referencing the fact that we need to steadily progressively increase our TSS? (surely you don’t mean step up TSS forever right?) or just increase our FTP slowly over time so that the same 2 hours of z2 one week will be 20 watts higher 6 weeks later but still be considered 2 hours of the “new z2” after testing?

anyways… my open question regarding aerobic base endurance… I no longer am completely certain what aerobic base endurance should feel like.
Xert has a neat metric called LTP… I tried riding 2 hours at what Xert thinks is LTP (Lucy in the sky with diamonds - 120). for Xert’s zones, LSD seems much harder than the TR version of LSD when you look at a ride like Conness for example… Conness has a similar amount of TSS as the 2 hour Xert LSD.

what this means is if you want to do LSD…long slow distance…z2 rides you need to go LOOOOONG.
2hrs is not long.
You’re going want to have 12-14+ hr weeks if you are taking this approach to get the value out of doing it, and one of your rides at least a week needs to be 4-5hrs.


Pretty much. If you can keep increasing TSS, hopefully fitness gains will come. Whether thats a higher FTP or a longer TTE. Its not a guarantee, but its a good place to start. In order to stress the system with Z2, you’ll most likely want to push those rides out to 4-6hrs. 2hrs will have benefits, but you will plateau after awhile. Thats why most people compensate with SS or threshold work, since it requires less time.

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At some point you need to increase hours or intensity. You can do tempo or SST intervals. After a block of that you may want to try the Seiler all-out 8 minute intervals.

In the end it depends on what you are trying to achieve. Unless you are racing or have a serious need to get faster just enjoy riding. You could always do fartlek style training - just throw a few intervals into the middle of your endurance rides.

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I have had similar experience to you, training hard 4 times a week isn’t sustainable for me (and I include SS as hard, it might not beat me up like work above threshold but that fatigue accumulates and eventually bites me in the arse).

My approach is therefore to train hard 3 days a week, and then the other 4 days is all z1 or z2 (apart from maybe the occasional sprint for a road sign on a coffee ride!). I pick the 3 hard workouts from the LV, MV or HV plans so that I get the workout progression from one week to the next. Might mix and match depending on my training time e.g. Take the long SS workout progression from the HV plan and the VO2 progression from the LV plan. On the Z2 days I don’t really worry about any kind of progression, I just pick a workout that is as long as I have time and energy for on that day. Might pick one that is towards the higher or lower end of Z2 depending how the legs feel, but as often as not I’m riding outside and using RPE and HR as much as power to pace myself.

Works well for me, ensures I’m getting the most important bits of the training plan, but gives me a lot of latitude both overall and day by day to adapt my training and recovery based on what I know gets results for me and keeps me motivated.


Yup. I did only Z2/MAF rides for a few months and it wasn’t until I started doing 5hr rides that my fitness really started to kick up.

Speaking of going loooooong…hope you have a few YEARS to train that. And I’m not for once being facetious, it is possible to move your VT1 up to your FTP…but it’s gonna take a LOT of hours. #noshortcuts


I guess one thing to keep in mind as well to grow aerobic capacity is to use the house analogy that gets thrown around by the WKO folks a lot.
Start by growing extended capacity at a specific work effort. ex. if you can do 200w for 2hrs make it 3, if you are doing sweet spot at 4x 250w for 10min grow it over a few weeks to 4x 250w for 20+min.
All of this makes the house wider.

Then after 4-6 weeks of that hit it with some anaerobic/VO2max work to lift the ceiling for 4weeks.

Your house just got bigger and you should see a FTP bump.

Now back to grow the extended at the new level, then hit it with some VO2.

This is basically the philosphy behind Base/Build/base/Build.


Just riding consistently in z2 will have a serious cumulative effect, which is often neglected. Some ten years ago I started riding seriously and, being from Scandinavia, picked up a long z2 base plus occasional sprints approach. The bread and butter, here. Did this from October to April, both on the bike and xc skiing, maybe 8-10hrs / week. In may I started 2*20min FTP, maybe once a week.

In june my anaerobic threshold was bumped from 210w to 300w. Raced okay that summer. Did not have a power meter then, just rode and skied with my hr below aerobic threshold a lot.

Would another approach have been better? Dunno. But just riding z2 can result in significant gains and stating otherwise is not very credible imho. Actually, a bit less total volume but dosed with higher week by week variation might have been even better.

Next season started SS, gained a lot quickly, and then completely burnt out.

These days I mix approaches, but z2 is king to me.


Agree with most of what you said, but would like to add a word of caution if you goal is to improve endurance with Z2 rides. You really need to know your zones. Don’t take a 2hr ride at max pace and try and push it to 3hrs. This type of ride would typically put you in Z3. Find your Z2, ride 2-3hrs in middle of that zone and progress the duration out from there. Aerobic decoupling has been a good metric for me to determine when I can extend the duration.

And everyone explains LSD as easy riding and just poking around. It is not that. That would be Z1 recovery. A Z2 ride for 4-6hrs is doable and repeatable, but does not leave you with the feeling that it was easy when you are finished. For those that have completed a century ride, it’s comparable to that.


Also want to be clear that TSS and “stress” are not always equivalent. TSS is a rather arbitrary calculation used to try and give an objective measure of stress. 450 TSS of zone 2 work vs. 450 TSS of Short Power Build are going to give very different adaptations and you’ll probably feel very different after those weeks.

Incrementally increasing TSS week over week can give good results if you’re comparing apples to apples. You may not be able to handle the same amount of TSS all in zone 2 or you may be able to handle much more than you could in Sweet Spot. It just depends…

My guess is that MV traditional base is not enough stress to push adaptation, and you need to supplement the two hour rides with a long ride on the weekend if you hope to achieve the gains you want from riding long and slow.

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100%, there is enough literature now i think that shows that riding at the top end of z2 produces no additional benefits over mid-zone, but does have the negative impact of "making easy rides hard"er than they need to be and takes away from the overall workout goals.


In general I agree and usually ride in the lower mid-zone myself. But two practical caveats may still be relevant.

First, for better trained athletes fatmax may occur in the upper zone two, and riding there occasionally is quite beneficial.

Second, for lesser trained athletes the neuromuscular side of things might mean that pedalling closer to the upper range feels more natural even if it is metabolically a bit more taxing. Holding back too much may result in an inefficient pedal stroke. Of course, it might be more sensible to try and fix that with short sprints and bursts, or not. But I see no great harm in riding in the upper range for a month or two before coordination allows for relaxed and efficient pedaling in midzone as long as the riding remains z2.

I have a similar dilemma atm.

Riding outdoor is now possible again and i do plan on doing 3 z2 outdoor rides a week (2-3h each) simply because i really enjoy riding outdoors again.

I still plan on doing 1 high quality session indoors per week and i’m wondering what kind of workout i should choose. Sweet spot work would be an ovious choice or maybe even a 40/20 workout which helped me a lot in the past.
What do you guys think?

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