Threshold Progression

You are hardly alone in that regard, believe me!

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Chiming in again. I did a vo2max mid-october but had to finish it prematurely due to the birth of our daughter and a subsequent covid infection. However, I still felt some of the positive effects of the block and tested my FTP at 340W (30min TTE). In subsequent weeks, training both threshold and sweetspot concurrently, I progressed with 2x22.5min, 1x50min, 3x20min for threshold and built up to 1x120min for sweetspot. I could not quite do 3x30min threshold with long rest periods, but 3x30min + 15min was still ok.

Now I did an intense vo2max block, after which I tested FTP at 350W (TTE 40min). This was early this week, and yesterday I already did 2x25min at 350W which felt manageable:

Doing threshold/SS work always feels very rewarding to me because the gains manifest pretty quickly from workout to workout. I have my first race in ten weeks, would be great to drive TTE to 60+ min before that! :sunglasses:


Last workout done, legs felt pretty fatigued but pushed through.

At the same time doing sweet spot progression just one workout left targeting 90-100min of work.


Almost all threshold progressions that I’ve seen have been simple and equal length intervals. I know Zwift and possibly TR include some varying lengths, but perhaps as much for interest as for science.

I’m interesting in these declining length intervals. Do you think there’s any scientific or physiological or psychological reason to favour them or disfavour them?

Does an interval below 10mins cease to be productive as a Threshold interval?
Does the declining duration help to keep the psychological strain down?
Is programming these just more complicated, so coaches don’t bother thinking past simple formulas?
What other factors are in play that I’m missing?

I do it purely for psychological reasons, threshold work is hard enough as it is any tricks that can make it easier I’ll take. Probably the most important thing is the total time in zone of the workout anyway.

I won’t go shorter than 10min interval, I was planning 45min+15min for the last workout to make it up alpe du zwift in one interval but legs weren’t feeling that great.


My guess is that in the large scheme of things, it doesn’t matter that much overall. If there was a study, it would show some not statistically relevant difference like the Seiler study. That study showed that 4x8s were “best” but not by a statistically relevant difference thus one could conclude that any of the interval sets were just fine and all accomplished the same thing.

I have read or heard that it takes maybe a couple of minutes for the aerobic system to ramp up so that puts more intervals at a disadvantage over less intervals. Like 3x10 is 24 minutes time in zone if it takes 2 minutes to ramp up. 1x30 would be 28 minutes of time in zone.

I guess if you’re playing around the TTE limit, you can either pre-plan some bailout breaks with some shorter intervals to grow Time in Zone or just bailout in actuality when it gets too hard.
Probably some subtle ways to manipulate intervals and rest into a fixed period of time, but pre-planning that is probably big-braining it unnecessarily.

4x8 at what %?

Maximal power, aiming to have interval 4 as close as reasonably possible to interval 1.


@ABG last month I did a progression 4x7- 4x8-4x9
I did what @Helvellyn mentioned. Average power for those intervals were around 105-107% ftp. It could be different for you. My main target was 105% but I went over :sunglasses:

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No, just need to reduce the rest as well, sometimes called “floating” intervals in the running world.

From Marius Bakken’s website:
“We would traditionally do two double thresholds with type 6-minute intervals in the morning and either 1-minute intervals (30 seconds rest) in the evening or alternated with 45 seconds intervals (15 seconds rest) – plus one more intense workout (an “X element”). Our shorter intervals in the evening would go slightly higher in intensity, usually right at or right above the anaerobic threshold, while the morning was lower.”

You can look up the Seiler study and read it. It has been discussed many times.

They compared 4x4, 4x8, and 4x16. The intervals were “iso power” - maximum but for the whole set rather than max for each interval with a decreasing power.

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I just finished my extensive threshold progression (shooting for 95%).

Started at 4x10 and finished off with 4x20.

I’m in my rest week now and feel like my zone 2 is +20 watts. First workout of next week will be a KM FTP test.


2x33 at 100% tonight. But, having prioritized tte, I have failed to do any specificity going into my first stage race next week. Will have to figure out how to add that in as I look to my A race in April.


This seems like a good thread for opinions. I’m taking two weeks off from strength training, which is my hardest workout of the week and crushes my legs for two or three days. I’ve been doing 5x3 vo2 on Tuesday; 90 min Z2 Wednesday, 30 minute tempo/SS effort on Thursday (50 min Z2 preceding it then 10 min cool down); then gym on Saturday with 1.5 hour Z2 afterwards and on Sunday.

I was originally thinking of doing 30 min SS (90%) Tuesday, Thursday, and Saturday with Z2 Wednesday and Sunday but now thinking why not four or five days per week for these two weeks before getting back into the gym. Anyone do SS five days per week for a very short block? How did you feel? I’d rate these 30 min efforts as 7.5 they’re difficult but definitely doable. Biggest issue is staying seated for 30 minutes things get a bit numb.

Assuming your FTP is vaguely correct, what you’re suggesting is to do 30 minutes at 90% at a duration at which you should be able to hold 100%. You’ll burn some calories, but I don’t think much else will happen.

I think it’d be better to do more time in zone for SS a couple of times a week than 30 minutes 4 or 5 times a week. You need some progression too.

Of course that depends on whether you have the time to spend 2 hours on the bike to push your SS out to, say, 3 × 30 or 1 × 60 + 1 × 30.

For the numbness, just go up a couple of gears and stand for 15 seconds every so often.


I suppose I could switch to 20 min, stand for 1 min, 20 min and call it 40 min TIZ. For those pushing 2x30 or 3x30 how much stronger - i.e. diesel power - have you felt? This year I want to increase my volume outdoors in the spring from 8-11 to 12-15 so I could see doing a couple long SS efforts each week. At 130 pounds my engine is a 4 cylinder hybrid so converting to diesel would be useful overall.

So I went through the SweetSpot progression out to 90 minutes for the last two workouts, took a recovery week, and now I’m doing a VO2 block. After VO2, I plan to do some Threshold work, extending out the time in zone. My question is, should I throw in a VO2 workout every now and then, or stick to nothing but Threshold? Like 2x per week Threshold, but every other week sub a VO2 workout in? Or once every third week?

After the Threshold block I’m doing race prep, so I could just do a straight Threshold block, and then I’ll get VO2 in the race prep work.

Are you an old person like what I am?

If so, sprinkling in VO2s is probably a good shout.

If you’re just a young pup - probably no need.

My wife says I am. :older_man:t2:

I’m mid 30s, so now Masters 35+ eligible, does that count?