Everything is a sliding scale. It's not like certain adaptations completely switch on/off with a tiny difference in intensity.

The classic vo2 max workouts are all above LT2. Yes they are harder to recover from than workouts around LT2, but the goal adaptations are different. Most elite triathletes will be using them, but maybe just some specific blocks - remember their training is periodised so is going to change throughout the season. As for the Norwegians blummenfelt supposedly has a vo2 max around 90, so maybe trying to improve it further is not a priority (it would take so much work for such tiny gains), and threshold training is clearly a more similar pace to Ironman. I suspect most age groupers could benefit from a vo2 max block.

It certainly seems that elite triathletes yearly training is more pyramidal than polarised (there is an entire argument over which is better for endurance athletes). There is a small study comparing polarised (75/11/14%) and threshold 78/20/2%) training in moderately trained triathletes. Found after 6 weeks of 10 hours per week training both groups improved a similar amount and concluded neither training was superior to the other https://www.frontiersin.org/...hys.2020.534688/full .

Sweet spot is well above LT1. Anecdotally a lot of people seemed to get burned out doing trainer road sweet spot programs, it's definitely way harder to recover from than training below LT1. I don't think sweet spot can replace traditional base training, but it might be a useful tool for time crunched age groupers.

Not necessary, but I find it useful because after ~35 years of endurance sports I've learned I'm not a particularly good self-regulator. Even with hard lessons learned. Ran myself into the ground in HS track. Rowed myself underwater at times in collegiate rowing. And on through life.

So I've learned to depend to trust metrics more than my subjective ability to gauge how much training stress my body is ready to absorb.

The notion that all training is pretty much the same, and you just have to account for durations is not something I subscribe to. I can do 20-30 hours/week @ 70% FTP continuously, no problem. Once I start to incorporate stuff over 80% FTP, I need to start budgeting recovery periods. Anything at or above VO2, and I have to be extremely careful with recovery periods. (this is just me personally, and I suspect I permanently damaged myself to some degree in collegiate rowing).

This is not what I intended to convey. The "pretty much the same" was in reference to training between LT and CP, which is roughly 75%-100% FTP.

It may not make sense to try to improve vo2 max, but what you want is power at vo2 max. The question would rather be if you can retain power at vo2 max without training it.

In agreement with the sliding scale, and the need to extend workout nearer LT1 and shorten workouts nearer LT2. I suppose the devil is in the details with this. If the sliding scale is linear, we would expect similar stimulus from 10 @ LT1, 20 @ LT2, and 15 @ halfway in between. But if it's exponential, as suggested by the lactate charts, the midpoint for "iso-stimulus" reps is more like 13.

The biggest headache with figuring out this type of training is that contrary to your last paragraph, these workout designs seem (and coaches affirm) easier than what most athletes would self-select. If literature is anything to be believed, a 20hr/wk athlete should be doing something like 45-90 minutes near LT2 4 times per week, plus races or short intervals on another day. That's a ton of volume at "threshold", so having the target off by a few percent could leave a lot on the table.

It seems, based on replies and some more literature, going over LT2 has a pretty steep drop off in total effect (by way of not being able to do as much), and going under LT2 has a drop off in effect as well, but somewhat lower. The game would then be maximizing training by getting as close as you can to LT2 for as long as you can without going over.

I'm not sure power at vo2max is particularly important as it's not sustainable anyway. Vo2 max is the ceiling, the higher it is the further you can push LT1 and LT2. If you already have a huge vo2 max your aim might be to shift lactate threshold as close to it as possible.

What literature? I'm not sure "the literature" has arrived at a broad consensus on intensity distribution and workout pattern prescription.

It's not linear. It's not as simple as tss might have you believe. Even if tss is the same for a vo2 max workout and a z2 workout the stimulus and physical adaptations are very different. You can't really compare them in any sensible way.

45-90mins near LT2 is not a lot. The classic threshold cycling workout is 2*20mins. For running lactate threshold tends to be something in the ball park of 10km race pace. Should easily be able to accumulate 45-90mins around LT2 with 2 workouts per week.

There is a suggestion that staying just below LT2 is better as you can accumulate more time, recovery is quicker, and it's more specific to triathlon than HIIT workouts way above LT2. However, it's nowhere near as good at improving vo2 max or anaerobic power as training at much higher intensities. This is perhaps where coggins 7 zone model is much more clear in terms of showing what physical adaptations differing training intensities target.

I was actually saying 45-90 minutes near LT2 per session. 4ish sessions per week, for 3-6hrs per week. I wish I would've saved the websites but a lot of interviews with the Norse coaches and poking through the limited strava feeds provides as much insight as I could get. It's striking because the 3-6hrs LT2/wk fits pretty close with the 80/20 model if your hours are 15-30/wk.

We're only talking about work between LT1 and LT2.


Yes, I was going to post this (the chart with check marks about halfway down https://www.trainingpeaks.com/...wer-training-levels/). Z3 and Z4 are quite similar in that chart. Is something like 4x 30 minutes low Z3 going to be the same stimulus as 2x 20 minutes mid-high Z4? Probably not exactly, but it will be similar according to the chart. To the question of whether or not being 10% low when doing "LT2 intervals" matters, I would say the chart suggests there would be very little difference between 2x 20 minutes at LT2 and 2x 25 minutes (or whatever slightly longer duration you can achieve) at LT2 - 10%.