Bring back the exact watt goals for workouts. Stop the rounding!

A couple of variables here so its not apples to apples comparison between our datasets - I am talking Zwift app only interpretation of block definition, not WOZ (likely not a factor), and I have two kickr’s in my house and I do know Kickr’s do things 'slightly" differently to other trainers (we have an ERG setting for workouts), and I look at actual fit files, not averages.

Probably to close off my validation (I’m not jumping on my trainer again until later today but will repeat my test workout and update later), daughter did a workout a few weeks back watching a movie and her blocks were 146 and 142 watt for a few hours (she wanting slightly different blocks so her legs didnt go to sleep despite my suggestion to make the gap wider!), anyway, here is an illutration of the watts she put out - these arent averages, these are the actual numbers matching that exact timestamp in the fit file


image

Point being they match exactly with the workout target intended and not rounded to nearest 5 watts.

Edit: If you want, send me your Zwift ZWO file and a workout you used it with and confirm your FTP setting for that activity. I’m now super-curious!

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I’ll DM you, I don’t exactly know how to do that :slight_smile:

I updated Aaron directly with pretty much below - conclusion is that we both have sets of data that look to support both actual target being sent to trainers as well as 5 watt rounded data being used.

Here’s what the Zwift ZWO file config looks like just for two of the larger blocks:
10min block starts here
<SteadyState Duration="600" Power="0.92000002" pace="0">
</SteadyState>
Recovery block starts here
<SteadyState Duration="360.00003" Power="0.55000001" pace="0">
</SteadyState>

Therefore Aaron’s FTP of 290w x 0.92000002 and 0.55000001

  • Steady state block target 266.8 - fit file avg 264 (starts to align with Aaron’s 5 watt rounding)
  • Recovery block target 159.5 - fit file avg 159.5 (too close make a call)
    Note I had removed the beginning and ends of each block to allow Aaron and ERG to settle into the block pace.

Whilst my FTP isnt as high as his, I will do the same workout that we’re comparing, albeit slightly shorter blocks and then repeat that on both my Kickr and a Neo that I’ll have for a few weeks.

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Unfortunately, the rounded power values are transmitted to the trainer!
Analyses with independent power measurement by pedals:



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As already pointed out by NikiT in February (!), Zwift causes disadvantages for women and lighter athletes because we find it harder optimizing our training - 5W stepping in workouts is too big. Please go back to the 1W power precision.

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I guess what I don’t understand, presuming there was a day when the values were not rounded(?), that wasn’t it more work and programming to change the routines so they do round to nearest 5W value, versus not bothering to calculate the rounded value and leaving it alone? What would be rationale behind the rounding?

Well, I checked old screen shots - John, you’re right, the workout power numbers in the HUD list on the left side have been nicely 5W stepped even back in 2020. However, I’m quite sure, that the power submitted to the trainer has been precisely dependent on the scaling factor in the .zwo file and the in game FTP bias - thus resulting in a big power number in the mid of the screen reading e.g. 243, see below.

Concerning “work” for the programming guys, hm, it’s just 7 letters code, round(). :wink:

Anyway, as shown above, rounding of power numbers AND requesting those rounded values by the trainer does not make any sense and should be removed instantly.

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I was wondering why zwift is rounding my power goal when using ERG mode in workout. Is this a bug or is this intentional ? (using Kickr)

More info on this old topic : " Bring back the exact watt goals for workouts. Stop the rounding! "

This was a test i did with 1w step

and this is the results on Intervals.icu (using strava)

Basically all numbers above 167.5 are rounded to 170 and below to 165. Why ?

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Dear Zwift Support Team,

the first time I started to use Zwift last year in October, ERG mode workouts had a +/-1w step granularity. That means, when my workout goal was 248w, Zwift workout told my trainer to use 248w and everything was fine.

During one of the updates in early 2022 or in December 2021, workout steps can only be used at a +/-5w granularity. That means, if my power goal is e.g. 248w, then zwift decided to round it up to the next 5w step, so it’s 250w instead of 248w. Same goes for workout goal is set to 152w, Zwift sets it down to 150w. You can’t really train on the watts you’re supposed to train.

A ramp up or ramp down step in a erg workout behaves the same, last year it was a smooth increase/decrease based on a +/-1w step. Now it’s like stairs, so the increase or decrease is based on the same +/-5w steps which is noticable during the ride.

Please change this behavior back so that we can train at the watts that we are supposed to train on and not on a round up/down based oin a 5w step value.

Kind regards,
Mike

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It has always been like this.

the actual figure it is trying to hold you to is correct only the display is rounded.

Hi Chris, thanks for mentioning this. But that cant be true, since I double record and I can clearly see the stairs on the ramps now. This hasn’t been the case last year:

Screenshot 2022-11-29 162331
This is a ERG Mode Ramp Up using Zwift from last October. It was a smooth +1w step up.

Now, it looks like this:

Screenshot 2022-11-29 162553
You can easily spot the stairs, each one adding 5w on top of the last step. There has clearly been a change in workout behavior.

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that is strange - it always used to be the case that the actual watts were correct but (for some unknown reason) the display rounded it to the nearest 5 watts.

maybe that has changed? i’ve not really noticed

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@Gerrie_Delport_ODZ Thanks Gerri for merging the topics, I knew there has been a thread already but hadn’t found it.

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this proves I should pay more attention while in erg mode! i hadn’t noticed this

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Yeah, this was bothering me a bunch so I did a custom Zone 2 workout and tested different intervals. Intervals.icu showed only the 5W increments as my workout meandered around in power by 1W increments. It’s not a huge deal, but on longer threshold workouts if I see it round up an extra 2 or 3 W it definitely makes me feel like the workout is much more painful :slight_smile:

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does this also happen with the +/- buttons? does it only actually change the resistance if you jump up a 5 watt increment?

Mmmm, did a 2x20’ FTP workout the other day (ERG mode) and the prescribed intervals were 2W lower than my saved FTP. I checked the power data on Strava and Garmin and they both confirmed the -2W difference. This 2W lower (than true) value was the same as the value shown on the HUD during the workout itself.

When I look at data for the exact-same workout performed on 5th Aug (diff FTP value), the prescribed 20’ intervals were actually 1W higher than my (Zwift profile) FTP, both on the HUD and in reality.

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I haven’t specifically tested this in intervals.icu but I ‘think’ it only does it in 5W increments. Can try this next time I do a Z2 workout.

Also note, I think it’s also possible that imported workouts might be handled differently than inbox workouts. But I’ve only tested this in my custom workouts within Zwift on my iPad.

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i’ll give it a go too. Would be interesting to find out.

seems wrong that you could increase it by 1% and nothing happens