3x20 SS is no joke

As the comment says above, ride hard or race and see what the top number is for HR and use that. I’ve found that as my fitness increases my max HR is higher than I thought it was initially (179 historically vs 184 hit this year).

But putting into context, hitting 145 on a SS interval when my max is 184, I might consider bumping my FTP if this was a recurring occurrence and not just one training session.

Hope that helps.


@Stringwise Well, I went back and looked at my Garmin history for the last year. It looks like my max is around 72. That was the highest I reached at the one race I did this year, a duathlon.

Should your heart rate be pegged or at an approximate percentage during sweet spot?

Last night I did over/under for the first time on Warlow and my heart rate maxed at 145. If my max is 172 then that’s about 85% My legs were pretty beat at the end.

If your max is 172 then I’d say 145 is probably pretty close to right. My max is about 200 and I sit around the high 150s or so during SS intervals.

1 Like

Just did my first 3x20 SS in a while, and my HR numbers are way higher than most listed here (as % of max)
Max HR of 186 (highest seen, on ramp test)
I did Tray Mountain, 3x20 at 90%.
For each of the intervals, my average/max HR was:

I have some over/unders coming up, so I guess that will be a good indication if my FTP is set too high based on my recent ramp test. Previously I have found that the ramp test derived FTP resulted in challenging but doable workouts (some vO2 max workouts were problematic.)

1 Like

I really think people need to test their LTHR and compare SS to that number, not max HR


I describe 3x20 SS as “I sometimes want to stop, but at no point do I need to stop”. More mental than physical. When I feel like I’m suffering, I just tell myself I should be able to do an hour at threshold straight and this is under threshold for only 20 minutes. Basically, just tell the legs to shut up and suck it up.

As far as HR, I see a decent swing depending on fatigue going into the workout. I can do 3x20’s and hit ~ 152 max on a Tuesday when I’ve had a rest day prior. Same workout on a Thursday (after a couple hard days) and I might be hitting ~160. My max is ~180.


IMO the upper HR limit of SST should be ~ 92% of HRmax for the bike, however depending on where your LT HR sits in relationship to you HRMax it might be a bit lower ~90%

90 - 92% is a good estimate. Upper limit of using HR @ LT is better if you know your LT heart rate, ie 100% LT HR, just my opinion based on what I’ve learnt, read and my experience.

That is normally about right for most.

Ha, I just put that is the best measure if known. Do you think (as I do) SST upper limit 100% of LTHR? My LTHR works out as ~ 92% of HRmax but of cause that will vary for each individual.

1 Like

As a cap? Sure. A bit of flexibility in HR variability day to day depending on hydration status, temperature etc. But in theory if you did a LTHR test of 30 mins at 100% FTP and take the avg over the last 20 mins, it should be higher than 95% of FTP for 20 mins total

Edit: My LTHR of ~190bpm corresponds to ~90% of my maxHR of 210bpm but that doesn’t necessarily hold true for everyone and true max HR not a lot of people know

Thats interesting, I see HR depression when fatigued. Can still put the power out but HR is lower than when fresh

1 Like

+1 to lower heart rate when fatigued. I’ve noticed it on many longer endurance rides after a food break. Still feel strong enough but depressed heart rate.

1 Like

I might see a little depression at the start when fatigued, but I see more drift as the workout goes on. When I’m fresh, I almost feel stronger on the 3rd interval compared to the first and see very little HR difference from one interval to the next. When I’m fatigued, each interval gets progressively harder and my HR drifts higher. I suspect it might correspond to my cadence increasing a bit as I struggle to push a big gear when fatigued.

Check your cooling.


I have a similar max HR and hr on eclipse when I did it on 20 oct was in the low 170s for all three intervals.

Just starting out here on TR with SSBLV1, although have mountain biked for years with 125+ rides per year and 2+ hour rides both weekend days plus one during the week/and some short bike commuting. I did Eclipse today, and after reading about the percentage of max heart rates that folks are working at here I might need to up my FTP. I’m only at 70% of max HR during the last interval, RPE isn’t too bad, and so far am waiting for workouts to get hard. Looking forward to seeing how Warlow/Palisade roll over the next two weeks.

Not Wright Peak but my own 3hr20m session including 3x 30M towards the begining plus endurance…

3x 30M @ 92% FTP rbi 4 minutes (yesterday 17/11/2019)

MaxHR of each interval 161 - 162 - 166 (started over heating in last set)

of LT:- 93.6% - 94.2% - 96.5%
of MHR:- 86.6% - 87.1% - 89.2

NB: MaxHR 186 and LT ~ 172

Picked two Eclipse workouts from previous years…
159 - 161 - 163 (LT ~172)
165 - 168 - 169 (LT ~174*)

*not sure how accurate the LTHR was, based on estimate

1 Like

keep doing it! raising HR each time shows that you can easily get a lot of aerobic benefit from doing these.

then, start elongating them to 30m, 45m, etc, all the way out to an hour!

Good luck!


Interesting data here, and of course it’s all relative to the rider. For me, it’s interesting how “easily” some others claim to complete long SS intervals like this. For me - everything about them is horrible, the duration, the lack of variation, and just how damn hard those long intervals can be.

That said - it’s something I really want to work on this off season! These types of training rides are something I feel like not only my riding can benefit from, but also the length of my season.

Maybe you’re not working at sweetspot but rather at threshold