Zwift - Power Stuck in Workout Mode

I've been using Zwift for years now. The one problem that I've been plagued with and have up until now failed to find a soution for is this - When in Erg Mode aka Workout Mode, very often the power setting gets "stuck". This means that despite the Zwift platform raising the power setting as the workout progresses the trainer remains stuck on some particular power setting. When this happens the whole point of Erg Mode is completely defeated. I've faced this situation literally dozens of times and like all "first world problems" it can be very annoying!

Online forums suggest that you toggle Erg Mode when this happens either by stopping/resuming pedaling or by using the companion app on your phone. Other more extreme measures include disconnecting the trainer from power and plugging it back in or worst case just starting the workout completely over.

Recently I've hit upon a theory and a fix that seem to be holding up. Time will tell if this is indeed the source of all the problems but so far so good.

The light bulb or Eureka moment came while in the midst of fiddling with the system because the power was again stuck. I noticed two things happening at more or less the exact same time. The first was that the power came "unstuck". The second was that the HR data - which can be seen as a red line going across the bottom of the screen with time - came back into view having dropped out for a period of time. So this was the basis for an hypothesis - what if the power getting stuck was caused by HR monitor data as seen by the Zwift platform dropping out?

This immediately made sense from a chronology perspective. It's pretty common to pair your HR monitor when you start (and you're cold) only to have the HR data drop out due to loack of skin-strap conductivity. Later on this never occurs because you're warm and sweating. This timeline matches exactly the timeline of the stuck power scenarios - they always occur at the start of a workout but once the workout is underway the problem never surfaces.

Armed with this knowledge I did another web search (I had searched plenty of times before this and either missed this report or ignored it) and quickly found a report of a user who had his HR monitor die mid-workout and power immediately became stuck.

So now things were starting to fall into place. It's been three workouts since my light bulb moment. In each case I made sure that the HR monitor did not drop out (mostly by pressing the strap tightly against my chest, sometimes by adding a bit of moisture) and in each case Erg Mode worked without issue - the power never became stuck. If this pattern holds up for another few workouts I'll be pretty sure that I've hit upon the answer for my particular case. Prior to this the problem was so pervasive that it would easily occur every other workout - maybe even more frequently.

Ironically enough - I had a similar situation in a very different domain that also plagued me for years, could never find an answer for online, and for which I finally found the answer. And the two situations are not all that dissimilar if you think about it. In that case I had a 1987 BMW which mysteriously would get "stuck" in low power mode whenever the car went through deep puddles or snow drifts. It took me years to finally figure it out but I eventually traced the problem down to the 02 sensor sending an incorrect voltage to the car's computer which caused the computer to go into "limp home mode". The more I think about it - the more similar these two scenarios are (despite the obvious superficial difference of the car scenario being due to too much moisture and the Zwift one being due to too little). In both cases the computer sees an anomalous "out of range" signal and goes into some sort of "degraded mode" so that things still "work" but in a way that provides a very sub-optimal user experience.

If the solution holds up in the Zwift case the problem will be solved for me personally, possibly for others who can apply the same workaround, and best case for everyone if Zwift can trace the issue down in their code and apply a fix. Even a warning message on the screen alerting the user to the condition would be better than what is there now.

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