Why Riding Slower Makes You Faster [GCN's latest video] Thoughts?

FYI for anyone wanting to go deep on Inigo San Milan’s philosophy, there’s a whole mega thread here: Iñigo San Millán training model


In the interview, I thought it was interesting how he mentioned that adding z2 at the end of a workout is not the same as the beginning. Once you bang out intensity, it takes 20 plus minutes to reset your body to benefit from z2. Which is also why averaging z2 is not the same benefit as a ‘clean’ z2 ride.


Yes, if you want to be time efficient doing these longer z2 rides, say 90 minutes to 2.5 hours, stick to z2 until then end.


Not the same is not analogues to not beneficial. I know that isn’t what you’re saying, but I just want to clarify that I understand that. It would of course be more beneficial to do my endurance riding before my intervals, but that isn’t an efficient way for me to train as I want to make sure I get my key “work” done, and as much volume as I can add within my normal constraints.

I’m not the one arguing that Z2 for 90min is the same as a SS workout of 90min either lol. Though I don’t see that many people out averaging ~80% for their Z2 rides. They’re different, both in use and benefit, I don’t think it’s a black and white thing.

Otherwise there would be no need for coaches or plans. Or gasp researcher.

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Totally, there’s benefit to added volume just not necessarily z2 benefit. At least not for at least 20 minutes after intensity. Changes my perspective a little.


That’s not how average speed works, even if you assume uniform gradients, wind conditions, and bike position the entire time - your speed can be different even if you average the same watts. This is because wind resistance increases exponentially


Watts are relative to the individual….so while his Z2 number may sound impressive, from a comparative effort level, he would find it boring. Just as I would find riding at 150w boring.

As to the “Z2 is slow”, agreed….I hate that characterization. I always say that LSD is Long STEADY Distance, not slow.


But on a quick look through the SS library on TR, which is what you were saying is the same overall work for, it seemed like more were ~0.8IF than ~0.7IF. I’m just saying the comparison isn’t quite clear cut like that.

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In terms of aerobic base you should add Z2 at the head of a ride. Once you’ve tapped those glycogen stores the benefits of Z2 are nullified (discounting calorie burn). At least that’s my understanding of the science.


My point is, that’s not the case in my experience. I think we just have very different expectations for our SS and Endurance rides.

I rarely do a SS ride with less than 0.85IF. I’ve never done a Z2/endurance ride north of 0.79IF.

I’m happy to concede your point about the value of Z2. Maybe one day I’ll try a block of just making it say 0.77IF start to finish for every single ride.

Great video. Thanks for sharing.

I think the video is talking about metabolic systems rather than watts.

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What benefits are “nullified” exactly?

Even at super easy the body uses glycogen. Depending on training status more or less. On the other hand, fat ox can be quite significant up into mid/upper tempo zone.

However, zone 2 is not just about fat ox and so. I don’t see how the mechanical stimulus, which triggers capillary growth in the muscles (more oxygen!), gets nullified by doing sprints early in a ride. It is even up to debate, if this fat ox depression after intensity is for real.


I did about 15-20 hours zone 2/week in lockdown in 2020. I really enjoyed it as I wasn’t at work. Did it make me faster in TT - no not that year. Although my endurance was much improved. This year my longest rides have been just over 2 hours at tempo. Plenty of 90min - 2hour SS rides and 10-25min threshold blocks within outdoor rides. Power is higher now in TT (and I’m 54 now). That said is it this years training that has made me quicker or am I benefitting from the good base I put in a couple of years back as riding for 2-3 hours now in zone 2 feels v easy. Who knows :man_shrugging:


They discuss it here. Z2 before intensity or different day. Not mixed in or after. At least that was my takeaway.


And progression.


Yeah, in practice it turns into a z2 HR ride which is not the same as SS in the beginning. But with a broad base of z2 HR you get to tempo power in Z2 HR eventually. (Some people probably get to do some SS within that).
After years of over coming health issues, I’ve finally been able to do LV TR plans this year. But now I’m back at work (special needs school) I can’t do intensity (even SS) without catching a bug, so z2 HR is my best chance at getting consistent training.


I get why if you want to be a strong rider you need lots of volume: to tire out your type I slow twitch fibers. And the only way to sustainably tire these out is to keep the intensity low and for pros who want to and can max out their training volume this is important but I don’t get how for us mixing in a bit of intensity this will nullify our z2 training benefit completely. I get you stop burning fat a bit and the type I fibers switch to burning lactic acid produced by the type IIa/b fibers in stead but the type I fibers are still being worked and so still should tire and get stronger from the training stimulus

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If riding slow made you fast I would be World Champion.


I did the slow riding experiment and it works. I did really slow based on Seiler’s HR estimates (125bpm) for me. After 7 weeks of 6-12 hour weeks that included one Saturday group ride with intensity, I was making new PRs left and right. The other 5-6 rides per week were those Seiler zone 1 rides. BTW, I ramped up the hours starting at 6 and adding .5 hour per week or so. I must have been at 10 hours per week when I peaked at week 7. I never took a rest week because I was never tired. My speed at 120bpm was super slow at the start and improved greatly with the training (like 12mph at the start and 18mph 7 weeks later).

I continued this for 11 weeks in total and saw no additional improvement after week 7. I think this is where I should have done what Overton calls ‘switching from base to race’.

Sweet spot is basically threshold training. I’m not even sure why it has a different name. 87%, 95%, or 97% is very similar and offers the same adaptions.

Kolie Moore covered the threshold training studies with Dr. Andy Coggin in the two most recent podcasts. (I really enjoyed these.)

I think the ultimate is to combine the ISM zone 2 work with some threshold training building out TTE. Toss in a short VO2max block after TTE is built out. Sprinkle in the occasional sprint. There, you have all bases covered.

(Personally, I think building out TTE is an under-utilized technique that many people aren’t aware of. People know about progressions but most people probably stop at the same point every time (2x20min or whatever).

Phil Skiba covered what to train in his most recent book (basically the upper and lower threshold). It’s a great book!