SST is typically a Power type target and I have never seen HR targets for that type of workout.
It’s not actually a distinct zone, it’s something that was ‘discovered’ and advocated to be ‘the best bang for the buck’. TR was all over the place with this and marketed SST as the best (and almost unique) workout for Time Crunched Athletes. And the result was that many users abused of this type of training, plateaued, overreached and even overtrained.
Now, if you go further on the Zone 2 Base training philosophy, together with the 80/20 principle, SST is simply a ‘hard training’.
For any type of intensity target that is related to physiological markers, there is always at least two approaches:
- Push up the floor
- Pull up the ceiling
Pulling up the ceiling became very popular because everyone was still in the ‘no pain, no gain’ thinking style. But depending on your talents and goal events, you can make the other choice or even mix both choices.
What follows is by no means ‘scientific work’, but it’s my point of view and based on very limited experience. I’m not a coach, but I like to know what happens in my body. I experiment a lot, but let’s be clear: this is what I found out, for my unique body and my specific goals.
When using a 3 zone system based on physiological markers AeT and AT you can use both push/pull and get different results. For base training, the message is starting to become clearer. Work below AeT and push up the floor. AeT HR will not change big amounts but it will slightly move up if you train for long enough with this methodology. Power on the other hand can really significantly increase as you become more efficient. But at a certain point in time, much later then most think, you will plateau and both AeT HR and Power wil stagnate. Then it’s time to start thinking of raising the ceiling by introducing smart work in between AeT and AT. By the time you get there, your AeT power is probably already in the lower part of Z3 Tempo (based on 7 zone Cogan system). And the gap between AeT HR and AT HR is becoming smaller. By now using the same system on the AT point, you can push up the floor by doing high tempo blocks (upper Cogan Z3 which is around SST). That will create more room in between AeT and AT. And it will happen rather quickly because you have such a large base. After that period, you can return to Z2 and further deepen out your base. Or when you equally find yourself on a plateau, start to pull up the ceiling by doing VO2 work.
Now which method do you have to choose?
If your events are long and steady state (Ironman, Ultra, TT,…) your best bet is to push up the floor. That favorises more durability just below those markers and is often a better solution then having a slightly higher threshold (be it AeT or AT) that you can’t hold for long enough.
If you’re more of a Crit rider, a sprinter or CycloX and aim to improve performance in the shorter events, you may be better of by pulling up AT. For AeT, I really can’t think of any reason to try pulling it up. Work above AeT is much more taxing then below and you will never be able to do enough volume to get a better result compared to pushing it up.
If you want to start out with Z2 (may get confusing now but here I mean Z2 in a 3 zone system) based on HR, add half of your age to your AeT HR and use that as a HR target. Start with multiple shorter blocks and work up to one large block. As a start, 4 x 10min seems reasonable. Then 3 x 15, 2 x 20 up until 1 x 60 or even 1 x 90min. Your guide is performance improvement. As long as you are improving, you’re training efficiently. Improvement here can be a higher power output overall or the ability to hold the power for a longer time.
I think it is apparent that the method of pushing up the floor is more conservative and implies less risk of overtraining/injury. So why would you want to do anything else if this works?
If it doesn’t work for you, try some pulling up but don’t just assume that if it works, it is the only thing that works for you. Keep the periods of this sometimes extremely demanding work short (4-6 weeks) and go back to the less demanding way of pushing up. There’s a very big chance that you will break that plateau after those 4-6 hard weeks. And you may be on your way for several more months of increasing performance.