rpm goes to zero during training

 I took part in group training last night. During the transition from high watts/high rpm to 30 sec rest, the rpm drop to zero and are all over for at least 15 secs.  By the time they correct themselves, we are back to the next set at high watts/rpm.  Is there anything I’m not doing right?  The screen keeps on flashing too much power but it’s impossible to drop from high watts to super low in seconds. 


Thank you for posting this. I’ve had similar experiences during individual workouts and I’ve not been successful in figuring them out.

Ca you share what type of trainer you are using? I think that will help some of the more experienced people here offer insights. I personally use a Wahoo Kickr (which I love). I
Just can’t seem to figure out how to slow the watts & cadence down to the rest targets fast enough. 30 seconds goes by so fast then I find myself failing the workout segment because I couldn’t keep the numbers in the target ranges. It’s kind of frustrating.

I look forward to seeing what kind of input you get in this post. I hope you find a solution. :slight_smile:


Thanks Carl.  I hope we get some answers.


I am using a Tacx Vortex.  I know it has an accuracy level of 90% but I don’t think this is about that.  I also don’t understand the ranges during the workouts. For some segments, I can go above the watts or RPMs by a wide margin; in others it’s so narrow I can’t keep at it.

Also, I can’t ride slow enough to meet the rest watts. I don’t know why they’re set so slow. It’s physically impossible for me to slow down to that level and keep the rpms where they want them. So I’m always failing a segment. So I don’t know what the implication is of failing a segment.  Does it hold you back the next time?  


If you have your KICKR paired to Zwift as a Wahoo FE-C controllable trainer, then Zwift itself will adjust your wattage to whatever the workout is calling for. You don’t need to think about it or do it yourself; Zwift and the KICKR will do that for you. The only caveat is that KICKR (at least the first generation) seems to have a minimum level they’ll run at it in erg mode, something like 47 watts. At least that’s our experience. You may not ever need to go down to 46 watts in a rest interval in a workout.

Cadence is under your control and you would need to follow the workout instructions by adjusting the cadence yourself. The KICKR will not control your cadence.



Understood that cadence in under my control but why penalize for being off?  At the extremes of watts I find it impossible to meet power requirements if I have to maintain required cadence.

The workout asks me to ride at 60- impossible to ride that slow.  No idea where that is coming from.  Crazy

Just decrease the gears, and it will be easy (it’s the goal) to pedal at this intensity.

Phillippe. That is what I do. But when I do that,  the rpm goes to zero. Everything wildly swings and by the time it corrects itself, it’s time to up the watts

Which instrument measures the pedaling frequency?


Thanks Phillippe. I saw your full explanation in my email but not here. That is too bad as you have offered valuable advice.  If I don’t drop RPMs quickly, then the program flashes both watts and RPM too high. Should I ignore that? Is there a penalty for staying out of the required levels for too long?  

You don’t care if it’s a matter of seconds.

Workouts are for improving your fitness level, not for getting awards.

  • The body isn’t a perfect machine which reacts/improve according to an absolute perfect timing, which would be exactly the same for everyone. You don’t care what it says on the screen, try to follow the program, the rest are details, for the most part due to equipment limitations.

  • These workouts are here to help, there aren’t what’s the best possible training. You use them if you want, but they aren’t the Saint-Graal of training. You have few chances to become better because you do something 35 or 25 seconds instead of 30, these are details. And the ideal value is a matter of personal attributes (which fluctuate with time and training), which you can’t find in such standard program you find here. Do them as you want/feel, keep consistancy, and you should improve for a long time (the lower the level, the easier to improve, whatever your training). 

Concerning pedaling frequency, you need an equipment on your bike, or having a smart-trainer which calculates it. Zwift only transcribes the data your equipment is sending to it.

Got it, Phillippe. So I just wish Zwift would stop flashing Fail!  I have a cat eye on my bike so I know my real cadence.  

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