Zone 4 training and threshold workout

Hi there all,

asking for some advice. I’ve been doing polarized training. I usually train 10hr or more a week and doing 1hr or so of threshold. The aim is to get to 300ftp (i sit now at 288)
My intervals are usually a 3x10, 2x15 and 2x20. Usually i start at a specific power (285watts now) and untill I don’t graduate from the 2x20 I’m not increasing the effort. I’ve now reached a point were i failed my 2x20. Do I keep trying the workout at 285w or step down and maybe stick to the 2x15 or instead do the 2x20 at lower watts?

Also this is linked to another question. Is best to complete an achievable workout or repeat and maybe fail multiples times a harder one until the body adapts (if it does)?

thank you all

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I would go for the same intensity at a shorter duration, possibly doing an additional interval like 3x15min or even 4 to 5x10 at slightly higher power before I revisit the 2x20.

There is also an extensive thread about SST progression that could provide some ideas.


Personally, I would not do the 2x20 over and over. That would get in my head.

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If you have time to experiment during base season, one possible approach is to combine Z4 and SweetSpot (instead of VO2max temporarily):

  • Tue/Z4: 4x10 → 5x10 → 3x15 → 2x20
  • Sat/SS90: 2x30 → 1x40 → 1x50 → 1x60
  • rest filled with Z2

For me this approach worked very well to improve TTE. Actually with slightly different progression due different starting point, but idea is still same.

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Perhaps you need a rest

It’s really hard to pick a number to try to meet. And if you are pushing out TTE (which it sounds like you are) getting a decent TTE at 300 watts could take a long time.

Depending on how “Trained” you are and how long you have been doing structure the gains come slower and are harder to get appreciate as well.

Also a periodized approach is also important. Doing threshold intervals every week is so taxing. This summer I did a sweet spot “base” block (working up to 2x30 at 90%), followed by a V02 block, and then 7 weeks of threshold, reaching 1x40 and 3x20 at 100% of my FTP. At the end of this I was WRECKED. I tried to do 1x45 after the 3x20 and knew 5 minutes in it wasn’t happening. I was just too tired from doing 2 threshold intervals a week plus zone 2 3 other days. I took two weeks off and only commuted on my bike - no structure. Now it’s back to base. You will flame out trying to push out TTE constantly in my opinion.

Maybe take some time off if you are failing 2x20 (or lower your current FTP if it’s not your actual FTP), and then do some SST/base training.

Just my 2c

have you tried doing over unders? just n=1 but I saw big gains in doing those vs static intervals and have changed up a lot over the past few years.

good luck!



What %FTP over and under do you suggest Brendan?

i really like 30s 120-125% and 90-120s @ 75-85%

then move the 30s to 45s

then add a 3-4m hard start at 110%

I don’t do the 105/95 a ton because that’s basically a steady state interval in my mind (others def disagree so take it for n=1 opinion)…but could make something more race pace paceline-esk like 105-110% over, 85-90% under…