Standard mode drifting power question

Equipment - gen1 cycleops Hammer, assioma uno

So recently I’ve been doing vo2 work on standard mode (level 1). Unfortunately didn’t record the trainer power on its own to compare, but was curious to understand the power drift across these intervals. Same gear/cadence, maybe slightly different muscle engagement at different times. I thought there was temp compensation in the trainer that wouldn’t necessarily require recalibration, but I might be misremembering. Of course, I could have shifted up a gear, but I’m on 8 speed, so the tends to put me a little too high power wise. Not sweating this too much since I was focused on the effort and not the power, but still curious!

  • Any form of that would only affect power data directly, and then potentially ERG mode use as a related offshoot of that.

For Standard mode use (1-9 scale vs 0-100% that is Resistance mode), it is “fixed” in the sense that the #1 setting you use has a certain power curve, that relates to the effective resistance force at a given wheel speed. If you are truly holding an even cadence as it seems, the only reason for drift is the result of electromechanical changes happening in the system.

AFAIK, the Hammer series is not dynamically altering the Standard resistance curve based upon system temperature. This is effectively similar to the shift in resistance feel in something like the old fluid systems that would change their resistance level for a given RPM of the unit from cold to hot temp ranges in use. In those cases, we had to alter cadence and/or shift to hold a given power target. That may well be what needs to happen here since it appears you are getting some delta in the effective resistance over time. That is sort of necessary in what is essentially a “dumb” trainer mode, and the apparent impact of altered loads from the trainer over time at higher resistance levels.

you didn’t hold power by changing cadence or shifting?! :crazy_face: Sorry couldn’t help myself, but seriously isn’t that a consideration? Resistance mode is like outside in that the goal is not to hold a steady cadence, the goal is to respond to changes in the environment and hold a steady-ish power.

Like you said, it didn’t impact the impact of the workout other than mental - you could have adjusted cadence/gearing and try to hold power better.

I’ve been doing VO2 max workouts in resistance mode this week. Here’s a 5x5 I did on Weds. I settled in at the same % resistance and same cog for the interval work. The tail off in power happened to me, but it was simply due to fatigue (reduction in cadence) as the workout progressed. Maybe the same in your case?

Not from what I see in his workouts. His cadence looks very flat and nearly dead steady, while you can see a fairly linear decay in the power registered as the interval progresses.

  • image

In your workout, the power decay closely matches a similar drop in cadence, so that makes sense to me.

  • image
1 Like

Ah, thanks for explaining :grinning:

Sounds sub-optimal. Perhaps a need to bump up the % to compensate for this issue if the cassette jumps are too large or cadence is already maxed out.

1 Like

i should edit the title, I was actually in standard mode not resistance, but level 1 in my text was correct. I’m done with this current block so won’t have a chance to test anything new, as I said I let the power report whatever and just closed my eyes (proverbially speaking) and pedaled hard for 5mins

1 Like
  • As someone who watches his cadence pretty closely, I applaud you for such a steady cadence without looking :clap:

Sorry to pile on this thread with a related question - does Zwift estimate cadence?

This was recorded in the gym over 5 years ago, on a Stages SC3 stationary bike. About two months before I bought a trainer.

Garmin 520 view:

and dual recorded with Zwift on my iPhone:

Just the intervals on 4x5-min at 120% climbing repeat (vo2) workout.

Why does the Zwift cadence vary so much?

One other explanation is possible…as it’s the one leg power meter version (uno): The effort was kept constant but during the interval there was a slight shift of effort between the legs (switch of dominant leg)

1 Like

quite possible, although i can’t say I can really tell, guess we’ll have to run out and get dual sided lol

1 Like

Sure an open variable. But I question how consistent L/R delta would be over time and between intervals vs the highly understandable case of a resistance unit shifting performance with heat gain.