Trainer difficulty vs workout resistance

I have an understanding of trainer difficulty as it pertains to hill gradient. The topic is covered well in many sources. However, I recently tried a workout while not in ERG mode and saw the incline feature on the ZC app. The icon seems to imply gradient and it seems to suggest that you can, for instance, change the gradient you are experiencing. But, I found an explanation that says it let’s you change your trainer resistance, which seems to suggest something different than controlling how much gradient you are feeling, which is controlled via the difficulty setting.

Pls allow me to set up a scenario that we can use to answer my questions below.

  • Trainer difficulty setting is at 50%.
  • In a workout.
  • Non-erg mode
  • Climbing Epic during the workout.


  1. While in a workout, does the difficulty setting ever truly influence the feel of the ride? I ask because there was a time in my recent workout when I could swear that when I hit the flat castle section, I had to pedal harder to keep up my watts. BUT, it wasn’t as drastic as when not doing a workout. Optical illusion or reality?

  2. While in a non-erg workout, what “resistance” am I changing when I change the incline? Am I changing the gradient? Am I changing the difficulty setting? Or is it something else?

Thank you in advance.

This shouldn’t have any impact at all. Your resistance is based entirely on your power/cadence. I’ve done a workout which got me to the top of ADZ and then depressingly down the other side, having to do threshold, and there was no change in resistance going downhill. I closed my eye to strop it being weird!

You’re basically increasing the resistance on the trainer to simulate the feel of a hill/harder gear.


Thx. That helps.

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I’m a little confused by something.

I’ve always associated “workout” with “erg-mode”. Your programmed workout adjusts resistance of the trainer based on the program. (150Watts NOW… software instructs the trainer to put on a resistance of 150Watts)

In a “free ride”, you’re in “sim-mode” (simulator) where going up a virtual hill increases resistance, down lowers it. In this mode, Zwift’s “trainer difficulty” slider simply makes a hill feel more real or not. (a 10% hill feels like a 5% hill at 50% difficulty). It’s not “cheating” anything as, if set to 50% difficulty, you’d be going 50% as fast up that hill - no free lunch here. (it’s like having an easier granny gear on your bike)

Alternately, if you’re in neither sim nor erg mode, you’re in “dumb” mode - which seems to be what you’re describing: you disable all software control of the trainer and simply mash a button for “easier” or “harder.”

In erg-mode, Zwift often has a “workout bias” setting where you can make the particular interval “a bit easier” or “a bit harder”. This is still erg-mode, but you retain some manual control.

Clear as mud?

Thx CJ for the effort in your reply but mud is a pretty good description. All I know is I did a workout uploaded from Peaks. I disabled ERG mode before starting. I did mountain route and climbed epic while doing the programmed intervals. I was in control of meeting the power expectations of the program versus my trainer forcing me.

I was curious if the difficulty setting that was in place before I started the workout had an influence on what I was feeling. I know that ERG removes the sensation of climbing and descending. But without ERG mode, do we get to feel the climbs?

There were times during the climb that it felt like I was feeling a change in the terrain but it could have my imagination as I watched my avatar level out or go down hill. :person_shrugging:

no in a workout you don’t get to feel the climbs. The trainer only get input from the user when you change resistance or changing gears.

Yes. imagination, I have experienced the same