Lesson learned - Difference between Xert workout and workout export to zwift

Hello, I rode the Xert gasoline workout today and noticed big difference between the work out planned metrics and the actual ride itself. See pictures for details. I executed the workout on Zwift under EGR mode; the ramps power values were pretty close from target. However, my actual MPA after 3x(4x2min) ramps were between 300 to 325W ! I got a near breakthrough. This is great but the gasoline workout is supposed to push MPA down between 615-650W for all 3 8min block. As a results, I got 147 XSS instead of 118 XSS posted by workout design window. See attached pictures.

Workout link

How would you explain this difference? I would expect a few MPA differences but not to this point. Is there something wrong with workout designer itself?

Workouts exported to Zwift can be a little different as all the Xert interval targets have to be translated to a percentage of the FTP that you have set in Zwift. Also ramps are always straight lines in Zwift, you won’t have that curve that you can see in the Xert workout. This usually means your power doesn’t decrease as fast so the workout is harder.

Anyway my rule is to never export a workout to Zwift if there is anything curvy in it. :slight_smile:


I’ve stopped exporting to Zwift altogether. I just let Xert control the trainer. Every once in a while I forget to untick the control in Zwift though, and then strange things can happen. :slight_smile:

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This is what makes Xert quite incredible. There is actually a HUGE difference between doing this workout in our system and doing the workout in another format (ERG or ZWO), as already noted by @guyc above. When exported to ZWO, our curvilinear intervals become straight linear ramps. Rather than decreasing exponentially from the start of the interval, the ZWO interval will decrease linearly, dragging MPA lower, making the workout harder, and resulting in more XSS.

We have a guide to running your workout on our system while riding in Zwift, which might be a good option for you. You can check that out here: The Ultimate Guide to Training with Xert and Zwift – Xert


This is an eye opener! I will certainly attempt the workout using the xert player next time. I was feeling pushing pretty hard lol!

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