Correct me if I’m wrong but the intention with splitting up the SS interval to say 4 x 10 as opposed to 2 x 20 is to make it more manageable to still do the same amount of work?
My question (assuming the above is correct) is, are there different adaptations taking place with 4x10 vs 2x20 or say 4x15 vs 2x30 and so on.
Furthermore, if you can handle 2x30, 2x20, 3x20 etc would you be better swapping out workouts that break the same amount of work up into smaller intervals for longer ones?
Thanks
The length of the intervals is related to the development of strength endurance, or the ability to maintain close to FTP levels for extended periods of time. Programs will typically start with shorter intervals to reap the benefits of working at that level, while giving you enough breaks to make sure you can accumulate sufficient time near FTP without failing. As strength endurance increases, the intervals will increase in length.
Ok makes sense, but to my other point, if you feel you have that strength endurance is there benefit to sticking with longer intervals of the same work time?
Yes, if you are capable of doing the longer intervals (assuming your FTP is set correctly, of course), there is benefit to the longer ones to further develop that endurance. This said, most plans start to shift from sweet-spot towards threshold workouts before reaching 20 or 30 mins intervals in sweet spot work.
Sort of, partially it’s progressive, to train your body to sustain that work load, the other part is to work at those higher intensities, which you can’t sustain for long. For instance, on the SSBMV1, Mount Field is 3x12 at 85%, and ericsson is 4x8 @ 88-94%.
I would say (without more context) depending on where you are in a training block, if the shorter intervals are too easy, might be time to reassess.
Stretch out the duration and go long if you can. That will give you the muscular endurance to push hard (up hills, into the wind, 40k TT) for long periods of time.
Thanks for the replies, I’m just starting my base but feel pretty good and when I see the intervals split into smaller junks my first thought is “I’m sure I’d be better lumping those together”.
I did a 2x20 SS in the week and did a 2x30 today. Today was at 90% FTP, it felt comfortable, I really think I could have done more, but obviously you need to be holding something back not over exerting in every session. I think maybe, that rather than 90% I’d perhaps be better aiming for longer intervals but nudging it up to a few % and seeing what the sensations are like and the recovery feels like.
That is one think I like about TR is that the plans give you the structure and what I’d class as a starting point, you can then customise depending on feel.
Wright Peak -5 is at 2x30 at 94% 
. That’s about as tough as they get, and if you can do that one and weren’t uncomfortable towards the end, I’d say your ftp isn’t correct.
Judging by your ramp tests, it could be as simple as your vo2 max is limiting your top end and your ramp tests are suffering.
So in the next couple of weeks really focus on nailing your vo2 max workouts and pay attention to what your sweet spot workouts feel like over the course of 2 weeks. I like a conservative approach, and bumping ftp on the final 1 or 2 intervals of single workouts, but if you find that across the board things feel easy then I would manually bump your ftp across the board.
Judging by my INSCYD testing from last week your VO2 comments are on the money. Still awaiting more feedback on the tests but I’ve attached them here in case they help inform decision.
Patrick Murphy MetabolicProfileReport-2019-12-03.pdf (1.1 MB)
Hmmm something I just spotted, despite pushing my FTP up based on the INSCYD testing via the TR website, it was still at 291 on the app 
. 282 may have felt more like SS than 273 did today. Damn it.
Well there ya go! A nice easy answer for now Update your ftp and go from there.
Data is interesting! 19% water storage huh… far off from a camel 
definitely. And keep extending, as far out as you can go. 3 x 45m is HARD. 1 x 90m is HARD.
Let it rip! Hope you are doing great and let me know which duration you complete down the road
Brendan
I wonder what the longest SS interval in the TR catalogue is?
AFAIK Phoenix +1 (90 min) and Polar Bear +1 (105 min) are the longest and range from 85% to 90%. So lower sweet spot.
I’m not sure that I have heard of different types of adaptations happening as you increase the length of a SS effort. You are trying to elicit anatomical adaptation in the shortest possible time with sweet spot.
So, as you are able to put together longer blocks of SS, you are able to put them into a shorter period of time. So you can get more work done efficiently. You really should be trying to increase time in zone as you go through the 4-6 weeks of your training plan. This way you are progressively increasing the load you can handle.
Unlike long Z2 work I’m not sure their is specific systems being trained.
Ah, that’s right, I remember Polar Bear.
For sweet spot work I agree with your idea of doing more continuous work and less interval work. That has worked better for me than putting together multiple intervals of sweetspot work.
I’m more into Phoenix, Gibraltor, Polar Bear when it comes to sweet spot work. Or even Lolita/Farquar if time is short.
By doing longer and longer sweet spot intervals, I can develop very strong muscular endurance (or fatigue resistance). I’m bigger rider and have climbed from sea level or foothills to the top of the Sierras. On these rides its common to have 1.5 to 2.5 hour climbs, and over a day can add up to 8 hours of climbing. Back here on the flats and rollers having great fatigue resistance has also helped on hard 3-6 hour group rides.
I use the workout creator to make my own 2x40 intervals where I add 20 seconds of high intensity every 5 minutes to break up the monotony.
Just hit pause and then slide the workout header to the start of the next interval and cut out all of the rest periods if you want. You can add them back at the end by adding minutes to your cool down.