Relationship between sweet spot and threshold PL

I recently saw Nate stating that for the moment an increase in threshold PL have limited or no effect on sweet spot PL as their data suggests that there isn’t much of a relationship between the two.

However that makes me wonder if alternating between base and build phases, as AT often suggests, gives the intended progression.

Using plan builder i got served up with a base 1, 5 week build, base 2 and full build set up. During base 1 I took my sweet spot PL from 3.4 to 6.5 and during the 5 weeks of build I took my threshold PL from 1.1 to 5.6. However, since I prefer to do a longer endurance ride on Sundays instead of a sweet spot ride, my sweet spot PL has now decreased back down to 3.9. Seeing the adaptations I got for the upcoming base 2 I will only be back at a sweet spot PL of 6 by the end of the block.

My PL ramp rate will probably increase more if I keep knocking my upcoming workouts out of the park and rating them as easy or moderate, but it still seems a bit drastic and detrimental to optimal progression to have to go through this PL increase again. Keep in mind that I haven’t FTP tested, meaning that an increase in FTP would lower my PL even more.

Am I missing something here or is it only me switching out the Sunday sweet spot workout that messes everything up?

woooh this is a big one, could you share where he said that? Keen to hear more about it

Been said a bunch of times on the podcast, it’s also been stated by Nate on here somewhere - 2 secs and I’ll look… Basically there’s less relationship than they expected (and for sure than people on here expect), but they’re open to updating it in future.

You’d also speculate the relationship varies between individuals as well.

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Here you go - he’s been a bit more explicit about it on the podcast.


so what this means is that if I were to extend my TTE at threshold this would not imply a similar extension at sweet spot level?

I’m thinking in terms of a typical gran fondo in europe where you have essentially long steady climbs focus on sweet spot should be preferable then.

Edit: had a look at the post. It would be nice to have a view from other more expert users. I’ll try to dig what other coaches are saying about this.

Yes, intuitively you would expect that improving TTE at threshold would also improve TTE at sweetspot and they’d track very closely. Be interesting to see what other coaches say but I got the impression it was basically that. Many people commenting in the big AT thread have also expressed confusion/surprise that improving their Threshold PL doesn’t also raise their Sweetspot PL (or not by as much as they would expect).

However, Nate says that their data shows a much less close relationship between the two than they were expecting.

I can only speculate, but there’s several ways to improve Threshold and it seems reasonable that some of them might not translate to long SS intervals - e.g., O/U blocks might not be that closely related to 15-20 min sweetspot intervals. And that would dilute the overall relationship between Threshold PL and SS PL in TR. But no idea if that’s big enough to create the effect TR says they see in the data.

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It doesn’t seem to be the case that the inverse, higher SS PL yeilds higher Threshold PL, is true (for me at least). I can do SS workouts at over level 10, but Threshold workouts at only 5-6.

Intuitively it makes sense that increasing TH would also increase SS. Practically speaking it seems that these energy systems are further apart than they appear

If you’re nailing that progression level increase on threshold and you’re recovering fine from your long endurance rides, I would highly doubt your SS progression level has fallen by 2.6 points. I have found that AT is great, but not perfect, and this is a good example where it might miss the mark. I’d swap your next 3.9 SS ride with a 5.0-5.5 level one and see how that goes. On the other hand, if you try a 3.9 level SS ride and mark it easy, AT might set you back on course more quickly than you think.

The biggest leap forward that TR has made is the development of the progression level algorithm, the first reasonably accurate, purely objective way to determine if one workout is harder than another.

Don’t compare those numbers. The scales aren’t equal.

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I’ll second what @patrickhill said. If you think your PL is too low in a certain area, use the workout alternates to pick a harder one that you still think is doable (something that would be classed as “Productive” if your PL was correct). If you complete that workout and rate it correctly, AT will take care of setting the progression.

Going off of what Nate said in the linked thread, they’re operating based on the model they’ve generated from the data. Very few of us will perfectly fit that model so use your judgement and the tools available to keep your training productive.

To be honest I also question the level of the workouts even within the same power zone but this is another topic.

To the argument though I’d also be inclined to say that training at SS does not push threshold in a significant manner. Hence many people might do well with SS and struggle big time with threshold once they go into build.

It actually depends on which base plan you do - high volume has all sweet spot, no threshold, while low and mid volume have at least one of each every week. The default mid plan has you ending base 1 at SS=7,8 and Threshold = 7,0, and low plan 8,6 and 7,0 respectively; high volume base 1 ends at 7,2 for SS, and not a single threshold workout done.

I ended up going for a 6.2 SS workout which was moderately hard, and I marked as such. Interestingly enough AT only adapted my next SS workout up to a new 6.2 workout, so AT and I still aren’t fully aligned on what my SS level is.

I’ll probably switch out my next workout with a harder one as well to get closer to my actual PL a bit faster. All in all not a big problem, but I still see it as a weird consequence of doing a combination of something that AT prescribes and TR suggests. (Doing a build phase between the base phases and substituting Sunday SS work with endurance work.)

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