Suprathreshold intervals are killing me

Howdy, I’m quite new to the forum, so be gentle! ha!
So today I attempted Jacks +1 after a recent biggish ftp increase. Needless to say, I blew up after 6 minutes of the first big suprathreshold interval. I decided to bail the entire workout and settled for some75 minute indurance work instead, which I can handle.

This is the second week I’ve bailed on these kind of intervals. I know I am struggling because of my recent ftp increase (I am now at 4watts/kg) - I was worried that my ftp was too high, so I recently tested it again and came out with the same ftp number, so I guess I should be able to handle these kind of workouts. Anyway, I was just after some words of wisdom as to how to get through these big supratheshold intervals. Any ideas? Or should I just grow a pair!? heh heh


Different Build Plan but same problem. Significant jumps in FTP each base phase and then struggling in Build.
I think this is partly down to giving it 100% on a ramp and pushing through mentally compared to a normal workout where its hard to give the same effort.
Also if a supra-threshold or any workout is a new Zone range, it will take time to adapt anyway.
There are many threads on this, but Back pedaling works wonders, get 99% of the workout even with 10-15 secs sprinkled in and do as many as you need to get through it. Physiologically and physically its really good.
If that is still too much drop a few %. The zones are a bit grey and so majority of benefit will still be had and much better than bailing.
If you search in the forum you will see that so many people struggle with these so you are not alone and this is common. They are tough. Getting used to them takes time.
Fueling these types of workouts is super important. Makes a massive difference both in energy and when you eat.
Some people do an adaption or bridging plan or V02 or Threshold block or some combo, both to boost these or to get the body used to them prior to going in to Build.

good luck


I am in the same boat, gained 5% on ftp and look at the work outs and think I cant do this.

I took a step back and looked over the steps that would allow me to be successful at these. Enough sleep, enough food, good music and send it. You can do it


What test did you take? Ramp test could well be too high if you’re relatively better at short efforts.

Also, what you’re capable of does vary day to day, and with motivation. Maybe you were fresh and motivated for the test, and less of both for your workout.


@brightontommy1 Jacks +1 is very similar to a Seiler 4x8 workout. So feel free to self select the intensity that gets you through 8 minutes.

Also, I know HTFU is a popular acronym on this forum, but also consider SWTFP. If a given athlete attends to over/under and extended sweet spot work only intermittently it should come as no surprise that endurance at or near threshold suffers. Stick with the plan or the plan will stick it to you.

4W/kg. That deserves congratulations for certain sure. Good job. Don’t rest on your laurels. 4W/kg for you is a step, not a summit.


Try a longer test 20 minutes or better still 30 minutes plus. Maybe base them on your ramp test result and see how it goes. That will reveal the answer or if aligned you might be one of many where all workouts based off FTP just do not make sense i.e those workouts above threshold.

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I’ve had the same problem with Red Lake +4 in sustained power build. It took me 4 attempts to complete that workout. (And then I abandoned that plan for general build, hah).

I really don’t understand why so many people seem to struggle with over-unders, that average out to FTP or even below, but there’s much less complaints about the supra-threshold ones.

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I might but it is a long conversation for another time.

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It’s because the threshold over-unders are in Sweet Spot Base. People either figure it out or quit by the time they get to Build.

Generally fewer complaints about VO2 over-unders as well, e.g. Mitchell and Xalibu, despite being harder.

Except people that don’t use TR find these the most difficult, it is in their design if you think about it. Don’t drag me in, :innocent: I need sleep soon. lol.

If it’s your first couple of weeks after a FTP bump I wouldn’t worry too much- it’s pretty common to need some time to adjust to the higher workload after a big increase. Also, if you feel your other workouts are at the correct level it’s less likely to be a FTP issue and more likely to be a relative weakness at suprathreshold work. Make sure you’re nailing your nutrition and cooling, try to come into those sessions relatively fresh, adjust/backpedal as needed, and you’l get there- and probably be a stronger cyclist because of it.

One other thing (and I’m always banging on about this) is that there’s a pretty big aerobic contribution to these kinds of efforts- so, depending on your training history and personal strengths, you might benefit from some additional base work. In any case, congrats on the 4 watts/kg!


I was thinking about the ones in sustained power build. Lots of complains about over-unders, a lot less about the supra-threshold workouts the same week. I’ve put the lack of complains about the vo2 over-unders down to those only appearing in plans the more vo2-inclined people do.

I do know what people find hard about the over-unders, lactate buildup, but no idea why the same doesn’t seem to happen in supra-threshold ones.

What kind of training were you doing previously and how long had it been since your prior FTP assessment?

There are two training history possibilities that are worth ruling out

First - if you haven’t tested in a long time, you might not have been adequately challenging yourself in what you previously perceived to be threshold intervals - they might’ve been sweet spot or below.

Second - if you have tested recently, but have been doing very little threshold or VO2 work then this might just be your body not being used to this type of work

It is hard to diagnose the problem without knowing the history you’re bringing into the intervals

N=1, but I find rides like Spencer+2 much harder than Palisade, even though I used to struggle with O/U quite a lot. I think they hurt me in different ways. Spencer +2 will have me breathing as hard as I can and right on the edge of stopping. Palisade is less… dramatic, but a little more painful. With a properly set FTP (or at least, properly set intensity for the O/U,) it’s the slowburn of lactic acid that gets me. I’m not breathing 10/10 struggling to keep going, I just want to stop.


Same boat here. much lower ftp at 3.7 w/kg. unlike you, I didnt bump up my FTP recently so let me tell you even if you are 100% sure your FTP is correct, 105% hurts!!

Week 2/3 of sustained build. First time doing anything at 105%

Original plan was 7 mins x 5, 9 mins x 4, 8 mins x 5

Dropped it down to 7 mins x 4, 6 mins x 5, 7 mins x 5. First time doing it (after a rest week mind you), I pushed so hard I was having stomach cramps. Even if your heart and legs are fresh its a workout you need to train yourself to do to get used to it.

I think I figured out that no matter what, 105% is going to hurt after 3, 4 minutes, I feel like this workout was meant for you to exceed your threshold and to KNOW that you can do it. I just keep telling myself, hurt - yes, uncomfortable - definitely, suck it up buttercup, the guys at the back are hurting as well.

on top of physically being prepared for the workout, I think you need to be mentally prepared for that 7 - 8 minutes. my max heart rate on the trainer was 180 previously, after doing the 105% workouts, I can sort of say, I can go 185 bpm for a couple of minutes and repeat it again. I needed to do this workout to say that yeah 180 is not my max, I can do more. uncomfortable is the new normal - my motto for sustained build.

not giving any advice, just wanted to tell you my experiences.

hope it helps.


cut the time to 5m, rest 1m, and go ahead until you complete total time in zone. eventually, remove those 1m chunks…
supra is tough; grit your teeth and crush it!!



Thanks Brendan. Wise words, I will definitely try this!

Thanks everyone for your comments!
It’s all a big help!

5x9min @ 102% was very hard today, I def feel your pain.

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He he, I thought that when I bottled on Carillon +2.! So you are not alone.
Fine to do the endurance work instead, but (in my opinion) a more effective, and satisfying solution is to either lower the percentage on the screen a few watts , or lower your FTP . I would go for lowering the percentage, because that will just affect the workout you are on. Are there other types of workout you find do-able at your new FTP?
Something Ive found is ,I struggle on the 1st interval, cant finish it, so lower the percentage a few watts. The the next interval I find easier, and I have been able to raise it up one or 2, so I end up pretty close to the 100 % and in that way I can get through the session. Hope you can work out a way to get through these. Hopefully wont feel so hard as we get used to this kind of training!