Automatic resistance variation WITHOUT ERG mode

It would be of great use to me for Zwift to be able to automatically adjust trainer resistance WITHOUT ERG mode.

I sometime do strength sessions using short intervals at high power (150-200% FTP) but V low cadence (45-60 rpm). Whilst I currently do these with ERG mode, it can be difficult to hold such a low cadence at that effort level; whilst avoiding the ‘spiral of death’. Yes, I could use the up/down keys to alter resistance manually, but this is not practical, particularly toward the end of a hard interval.

What would be ideal is to have the trainer resistance adjusted automatically but without controlling for a fixed power - just increasing the resistance to an arbitrary level. I could then set this ‘arbitrary level’ in my workout plan and with a bit of trial and error get it to set the right amount of resistance for my intervals, but without the difficulty of avoiding the ‘spiral of death’.

These type of intervals are very much bike specific weight training, and I find use of zwift and a smart trainer a very effective way of doing these, much easier, more controllable and practical than sprint intervals in a big gear on the road, but it would be better still to just have the automatic big increase in resistance but without the associated difficulty of ERG mode.

Hi Mark,

I am interested in this post, I do all my workouts with ERG off. I may be a bit slow this morning but I don’t fully understand what type of control you need.

Do you need Zwift to Automatically jump to the next resistance setting when the workout block change.

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Gerrie -

Yes, that is what I would like.

A typical workout would then be a 15 min warmup, followed by typ 5-8 intervals at 150-200% FTP lasting about 30-60 seconds each with 2 mins easy (50% FTP) in between. If the difficulty just increased in proportion to the level of the workout block but without the active control to hold a certain power that you get in ERG mode then it would make it more straightforward (easy isnt really the right word!) to do this type of workout.

I think that the ability to do this type of session is something thats almost unique to programs like zwift and smart trainers. The road equivalent is sprint intervals on the road but they arent the same as the cadence is too low at the start and too high at the end, plus the practical difficulty and safety aspects.

Thinking about this a bit more, one possible implementation would be that the workout blocks become ‘gradient’ rather than power, so in my case the intervals could be e.g. 15% gradient and the rest periods flat road. So this would be a an additional sub mode within workout mode, a sort of user defined ‘sim mode’.

Perhaps like the resistance mode on the Wahoo KICKR (and on other smart trainers):

These modes are available for KICKR control:

  • Level: Choose your power curve! Just like riding on a fluid or wind trainer, the faster you go, the harder it gets. The level you select determines the progression of your power curve.
  • Resistance: Just like adjusting the brake in spin class. For those who need complete control, this allows you to set the resistance of the brake manually anywhere from 0 to 100%. Regardless of speed, resistance will remain the same until otherwise changed.
  • ERG: Our personal favorite - intervals have never been easier (or harder)! Set your desired power and watch as the KICKR adjusts to keep you honest during training. If your cadence drops, the KICKR will increase the resistance to maintain a constant power output, regardless of speed. It’s the ultimate way to train - with power!
  • Sim: With Sim (AKA Route) mode, enter your weight, bike type, riding position, headwind, and grade to have the KICKR accurately model the power curve as if riding outdoors. When using this mode, ensure your weight and tire size is properly set in the KICKR’s sensor settings for accurate power calculations.

Steve -

Yes, does sound like auto resistance setting for Kickr. I use Tacx Neo, so should be possible with this, or indeed any direct drive smart trainer.

Mark: I had a similar request about 2 years ago. My idea was that the resistance slider that you see when you press ± be divided in equally and that would correspond to Z0 to Z5. so if the workout is in Z1 the slider will be almost at the bottom, and if it jump to Z5 the slider should go to the top. I currently do all of that using ± but it will be nice if Zwift can automate this a bit. I don’t mind changing a rear or to to get to the exact number.