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

But…but…where is AI? :wink:

And to be serious - after many experiments, what you described works for me the best. Z2 as a base of every week, then fill with intensity - threshold 2x week till i do not see improvements, then vo2 block and repeat. Progress TiZ and volume. Recover when you can. Reducing volume causes reduction in performance, increasing volume is followed by performance increase. That’s all for me.


Just an observation, but it sounds like the gains you saw were actually from the previous workload and the easy rides allowed you to properly recover (which allowed you see those gains). This could also be the cause of no improvement in weeks 8-11. Not switching from ‘base to race’ as you say also likely played a role.


We were discussing adding Z2 after an intense interval session. Not “mixing in a bit of intensity”. My understanding- and I’m not sure if you watched the video I posted- Is that if you want the benefits of Z2 it’s best to have it before your intervals and not after. I should also note they discuss adding as little as 60 min of Z2 as opposed to the long hours you mentioned.

I watched it and the entire Attia podcast too but it doesn’t answer my points. As I understand it you start out with using just your type I fibers as you require more and more power more fibers are recruited until you start tapping into your type IIa/b fibers. Type I fibers basically can use anything as fuel (fat, glucose, lactic acid), type IIa(/X) are mostly glycolytic but can use fat to a degree and type IIb are glycolytic or can use the phosphocreatine system. Why would using these other muscle fibers affect the training of type I?

Looking abck on it, how much of that gain was due to adaptation & how much was due to supercompensation from whatever training load you had just accumulated prior to adopting a polarized approach?

Also, what was your overall training load trend? I assume ctl probably trended UP when you switched to a polarized approach…but thought I should explicitly ask. Yours is a very interesting anecdote. Thx for sharing.


Great questions. Well above my level of intellect. That’s the way I interpreted what they said. Maybe we could ask them for clarification.

Intuitively it makes more sense to me, and it’s the way I train. Training so that I can ride several hours of Z2 and finishing with 30 to 60 min of intensity, helps me prepare for races both physiologically but also mentally. Knowing I can push those threshold numbers and above after the Z2 as opposed to before. I’m my Mind. If I’m going to tack on some extra Z2 it behooves me to do it before. Bro science! Lol.


I’m not sure how one would even know.

I was not tracking CTL back then as I only had power on my trainer but mostly rode outside. At the time I wanted to try polarized because I had just stagnated. I’d go ride, chase Strava KOMs, do some intervals, and do my group ride on Saturday. I was in this rut of constantly needing to recover from the group ride, the intervals, or the KOM chasing.

Last year, I switched it up. I did a lot of ISM Z2 in the fall through Xmas with zero intervals. I was doing about 8 hours per week as I didn’t have the time for any 12 hour weeks.

Then in January, I switched it up and started doing Steve Neal style tempo intervals. To me, this is basically low sweet spot or you could call it “threshold lite”. More importantly, I built out my TTE on these intervals to 80-90 minutes of tempo (4x20 or 3x30). By June, I was hitting my highest numbers ever but I also had more durability and endurance than ever.

Managing fatigue with the tempo intervals did become a challenge along the way.


Oh, yeah. I agree. If you don’t keep track of training metrics it’s probably impossible to say one way or the other.

Not necessarily true. I am currently in similar base phase (12 weeks total, in 3 blocks with 3:1 on/off) like @AJS914 described except before that I had 3 weeks off due injury i.e. no hidden delayed improvement.

  • 1st month: 6x Z2, capped by HR (around 60% of FTP), FTP increase 2%
  • 2nd month: 5x Z2 + 1x Z3/Z4, FTP increase 3%
  • 3rd month: 4x Z2 + 1x SS + 1x Z4. Will run FTP detection after next recovery week but just today did Z4/80 2x40min (substituted from SS90/120 1x120min because assumed it to be too easy considering last week SS90/105 1x105min :wink: )
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Above mine too, so I pulled out Dr Phil Skiba latest book. There isn’t a lot of studies on low intensity cycling, because of logistics of finding athletes and how long the study would need to run.

But there are some studies, and some strong empirical evidence that spending time at low intensity is correlated with improved fatigue resistance, lactate clearance, and performance.

Think about it this way, you do sprint intervals to target specific muscle fibers and/or groups of muscle fibers. The same with vo2max intervals. The same with threshold intervals. Etc., etc.

Why wouldn’t you want to do the same with slow twitch fibers? A couple obvious reasons are how long it might take to stress them, and boredom while doing low intensity.

What is clear to Dr Skiba is that long, low intensity efforts can have a dramatic impact on increases in mitochondria, capillarization, and other determinants of aerobic fitness. However it is difficult to document over the typical short term studies that are done. One good study tracked rowers over 3 decades, another of British elite rowers showed speed increases at LT1 for rowers that trained 100% below LT1, versus rowers that mixed training with 70% below LT1 and 30% above it. With cycling there is evidence that long-term low-intensity training results in performance increases such as reduction in slow component of vo2, and the often mentioned ability for elites to generate high power outputs after long durations.

FWIW my personal opinion has long mirrored what I hear ISM say. Put in some good work (90-120 minutes) at low-intensity and then throw down some hard efforts at the end. Do some sprints, go for some 1-4 minute KOMs, whatever, as long as it doesn’t impact upcoming workouts. If I happen to do a hard effort early on, don’t sweat it, just settle back into low intensity and keep going knowing that I’m accumulating a solid 4-6 hours of steady low-intensity a week, and my belief there is evidence in my own data of a cumulative effect from doing what amounts to endurance maintenance work most of the year.

That’s one science opinion plus my thoughts, there isn’t a lot of endurance coverage in Skiba’s Scientific Training for Endurance Athletes as its pretty simple training. He does suggest adding some tempo into long rides, to reduce boredom and induce more metabolic adaptations. Something like a 4 hour endurance ride, with 3x10-min of tempo, and capping any hills at 95% FTP (he actually uses CP, which is a little higher than FTP).


Being the expert that I am (sarcasm/ been riding 18 months, 5 months structured, 3.8 w/kg) I agree.

Obv pending time of year. If I had 6 hrs to train a week it would be 2 x 1 hr or 3 x 45min in Z/4/5 and 1 x 3-4 hr or 2 x 2 hrs Z2 outdoors. I train double that and add an extra sesh of intervals and an unstructured ride based on feel (ie a bit of everything).

Again, I’m new. This is what I would do, I understand it’s based on limited experience and personal preference and I’m not a scientist or coach.

I’m new so race in the weak sauce of 70 mile fondos (3:15-4:05hr Range) and thus far have podiumed 3/3 With 3rd, 2nd, and 1st place overall out of a mixed field of 400-600). Based on numbers I’m a Cat 5 but I attribute my results to the Z2 and being able to push threshold/Vo2 in the last hour.

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Everyone needs to find what works for them. I’m tall and built like a rower, with a big chest. I’m not aero. The engine at threshold is 3W/kg / 270 ftp, which isn’t enough given my build when riding with peers that have been cycling for 20 years. I’m sixty and have always, since middle school, had a mediocre top-end / vo2max. All this endurance work has raised my top-end with very little top-end work.

No surprise I’m not competitive, but I love cycling and have gotten faster two very different ways - newbie gains at 7+ hours/week and more “intensity” than TR mid-volume plans, and last two years 7+ hours/week working with a coach to figure out how to train for both health and performance by doing a lot of endurance riding. The before-TR way wasn’t sustainable, the TR hybrid MV 5+ hours/week way dropped volume too much and I got slower while not having enough base and blowing up in build (before AT), and the way I’m training now is working far better than expected and there is both science and evidence to support this approach over slamming 4 days/week of intervals in a 6 hour/week MV plan (pre-AT). Its pretty clear to me and coaches that looked at my data, that I’ve gotten faster and healthier with this approach. Works for me. Your mileage may vary and all that.


By definition, you can’t have a Z2 ride above .79IF….or even ~.75IF, really


I ride Zone 2 at whatever intensity I feel like it.
~ Napoleon Dynamite



That’s my point


The one question I wish gcn had asked would be something along the lines of how long it takes before you see improvement.

Sweet spot has relatively quick gains and moving over to lots of z2 you might not see the quick gains and revert to smashing all the time.

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Question here… according to this diagram (with the benefits by zone), which benefits do you get in Zone 2 that you don’t get in Sweetspot or Threshold?

Is it only fat burning?


Yeah to me the only benefit seems to be that you can get in much more volume with z2

It would have been a good question to ask, but I am afraid the answer is too much in the realm of “it depends”.

For me, it has taken 2 years of training with a coach to really really see the benefits.

The first year was pretty much just adjusting the mind and body that I need to build the base, from scratch. Second year has been transitioning into more volume (10-13 hours per week), but also being smart with intensity, one LT1 interval per week and one LT2.

Either way, it takes time. TRs business model would never work if they said, hey, you need 2-3 years before those base rides really show their effect.

With that said, I think that GCNs video might have been the best one so far in explaining why the “regular cyclist” needs to ride easy, and how those benefits actually translate into performance over time.


Even at 85% vo2max (~FTP) there is still plenty of fat ox going on. The more trained, the more fat ox at higher intensities. Intramuscular fat droplets can be found mainly in the proximity of slow twitch mitochondria.


So riding at 65% vo2max is good for mitochondria and the fat ox above is bad?