Tx for that article. As it turned out my legs were so knackered I immediately realised that vo2 max wasn’t happening and just did one 8m @103% and rest of 2h ride mostly in Z2 and took a rest day yesterday. The TSB (form) thing doesn’t always work out. According to that I should have been able to go hard 
I am going to be making the fitness and fatigue factors for the fitness chart configurable soon. Maybe at 48 I need longer recovery!
Going to see if I can do the 2m intervals today.
It will only get better - trust me, I’m turning 60 soon 
Found this on the TrainerRoad forums: https://www.wattkg.com/long-intervals/
This study demonstrates that a 4×8 minute interval format induces greater performance enhancement in a group of recreational cyclists when compared to 4×16 minute “threshold training” or 4×4 minute “VO2 max training”.
Nevertheless, it appears that a working intensity of about 90% of maximum heart rate allows for a beneficial combination of sufficiently high intensity and long total duration of work.
So maybe I should dial it back a bit and go for 4 x 8m?
Phew got em done. First couple a bit short (ran out of hill) but I did more power and the rest were a bit longer. The 2 x 8m give more time at above threshold HR than the 8 x 2m.
This study demonstrates that a 4×8 minute interval format induces greater performance enhancement in a group of recreational cyclists
The operative work here is recreational cyclists. Going on the VO2max figures quoted probably have not done a lot of structured training. The 4x8 minute intervals over 7 weeks gave then the biggest improvement.
However the review also compared to the 30/15 interval study that was tested over 10 weeks on competitive cyclists and given their VO2max averages, had done considerable structured training and at least CAT 3 if not higher.
The conclusion I would draw is medium intervals aka 8 minutes for those starting out structured training a bigger gains and shorter intervals 30/15 seconds are better for riders with structured training experience.
ps given the FTP quoted, you belong in the second category.
I need to look at trying 30/15s. What I did test recently is doing the “hard start” thing (first 30s to 60s or so at 120%). That got me more time at above threshold HR without losing much power. Did it for intervals 2 and 3 here.
Have a listen to this podcast about VO2 max intervals.
One of the things that interested me was that 30/30 protocol increase VO2 max but aren’t as glycolitic as the longer intervals
Hello, I don’t understand the glycolytic stuff. The glycolytic pathway if for sprints and short bouts, so the shortest intervals use it and stimulate its growth as far as I have understood INSCYD stuff and VLaMax
In the Seiler study athletes have a VO2Max around 50 not so bad for people around 40
I don’t understand it either really. I was just quoting from the podcast from someone who seems to have devoted his life to understanding it. My first thoughts were that it might be that as the durations are short followed by rest intrevals lactate doesn’t have time to really build up in your blood.
Hello, thank you for underlining this stuff because there is something to learn here !
In the last six months, I have listened and read about VLaMax and lowering glycolytic capacity in order to maximise my endurance as long distance triathlete (cf INSCYD theories). So far I have understood that short efforts stimulates the glycolytic pathway (glucose->lactate without O2) Then after producing a good amount of lactate, your body uses it so it relies less on fat oxidation. That’s why it is not a good idea to sprint for the next road sign or to burst climb up a hill when you are riding with budddies with the goal of a long slow distance ride. That’s also why I was more inclined to do “seiler” 4x8 min intervals in the beginning of 2020 to be in line with this idea of avoid the stimulation and growth of VLaMax with short bursts of efforts. So listening to Larsens’ podcast, I guess I might be on a wrong way.
So I listened to the podcast and around 27:00 Dr Larsen says that the short intervals do not rely that much on the glycolytic pathway. He says it but I don’t understand why. He underlines that lactate doesn’t build up in the blood but there might be a lot of lactate in the muscle which enters the citric cycle afterwards. And maybe the rest intervals gives time to “eat” this lactate so that it doesn’t escape that much in the blood to be metabolized in the liver or elsewhere, hence the 4 mmol/l lactate. But to me it’s not a proof of a low usage of the glycolytic pathway. I will have to buy its book !!
The more I think about it, I think 8 min intervals might be great to boost VO2max during a first block of the season, then approaching to the race I should focus more on tempo/threshold training to decrease VLaMax. It’s an idea, gonna dig this.
it seems that it is the shortest HIIT intervals which rely a lot on myoglobin that stimulates less the glycolytic pathway. So maybe doing 15-15 is a way to work on aerobic and neuromuscular compartments without stimulating too much VLaMax growth
High-intensity Interval Training, Solutions to the Programming Puzzle. Part II: Anaerobic Energy, Neuromuscular Load and Practical Applications](https://pubmed.ncbi.nlm.nih.gov/23832851/)
Sports Med. 2013 Oct;43(10):927-54.doi: 10.1007/s40279-013-0066-5.
Have you seen the price of his book? 
yup ! I have found explanations on You Tube videos and scientific articles.
To minimize glycolytic contribution, I imagine doing 30/30 with a raisonnable goal of 100% MAP on the intervals. This way you have some kind of stimulus of VO2max without too much strain on the glycolytic pathway. It’s what I have understood from their classification of HIIT workouts.
HIIT Science is a great resource and provide a lot of free information on their blog & social media. The book is (probably) well worth the purchase, but all the information is freely available in their two papers that led to the book.
Buchheit & Laursen, 2013. High-Intensity Interval Training, Solutions to the Programming Puzzle:
Part I: Cardiopulmonary Emphasis.
Part II: Anaerobic Energy, Neuromuscular Load and Practical Applications.
I’m very interested in this topic as well. From the article I just posted (thanks @david for linking! 
):
For example, could depleting those anaerobic pathways early in the hard-start interval tend to cause VLamax to increase, as glycolysis will be preferred by faster fibers to rapidly restore homeostasis? Whereas more gradual, progressive fiber recruitment in an evenly-paced interval may allow greater fat oxidation across more fibers as they begin to contribute directly to mechanical locomotion?
As for 30/15s & intermittent intervals, I’m still thinking it through.
From Ronnestad’s papers: BLa response appears no different to an acute workout and I don’t think RER is reported, so it’s hard to say what’s going on there… After the training intervention peak BLa tended to be higher during performance tests, showing increased accumulation or ‘tolerance’.
W/BLa (a very crude and possibly meaningless measure of fermentative metabolic contribution to power) tended to be lower in the short interval group after training. Suggesting greater oxidative activity relative to glycolysis, ie. more pyruvate was oxidized before needing to be converted to lactate for transport through the blood.
Plus the improved performance at 4mmol BLa (higher power and %VO2max utilization) suggests 30/15s training did decrease VLamax.
And that doesn’t even get into the muscle oxygenation data during intermittent intervals! Which I haven’t seen much of in the literature, but I’ve been experimenting with myself. Definitely some interesting implications for describing what’s going on in the local muscle
Definitely for a coach, but a bit much for an interested amateur despite only being the price of a decent cassette. It’s amazing how we value things differently and illogically.
Hello, I don’t read this in the 2015 paper, can you point me to where you found this ? is it in the latest paper with elite cyclists ?
Do we hypothetize here that the Glycolytic engine has build up ? Without the results of the wingate test with lactate it’s hard to tell… I don’t think the power @ 4 mmol of lacate tell you something on VLaMax, especially knowing that VO2 has risen. Can you give us more explanation on your physiological hypothesis here ? thanks
Thanks Remi. Yes that’s from the group’s recent 2020 paper on elite cyclists. Free download available on Researchgate
Sebastian Weber actually just commented basically the same thing on my article. I just posted my response to him.
Briefly, I have been using ‘VLamax’ as a proxy for something like ‘how much glycolytic, and specifically fermentative (lactate producing) metabolism is contributing at a given intensity or workload’. But that might be a mis-use of the term.
You’re right that the reported data in the Ronnestad et al paper do not show anything related to VLamax, literally as the peak rate of BLa accumulation. But for the reasons given in my comment, it seems to me that enhanced substrate efficiency (greater relative contribution from fat oxidation) at submax would suggest lower VLa(submax) at least.
My question to Sebastian was basically whether a change in VLa(submax) also implies or requires the same directional change to VLamax? 
Not sure. Interesting to think through the physiology!
Any thoughts?
