Zwift Bans Two Riders for Manipulating Race Power Data

November 19, 2020

LAST UPDATED November 19, 2020

Zwift has just announced sanctions against two riders, giving each a six month ban from Zwift Cycling Esports events after it was determined they fabricated or modified their racing data, “bringing the sport into disrepute.”

The notice of sanctions can be found here, which links to detailed PDFs explaining the Zwift Performance Verification Board’s (ZPVB) decision in both cases:

Violation Details

Section 2.5.1 of the Zwift Cycling Esports rules state that:

“The smart trainer or smart bike must be the primary power data source…” and
“Riders must record a second source of power data“

So two sources of power data are required, the power numbers sent to Zwift have to come from the riders’ smart trainer/smart bike, and not their second power source (typically a pedal or crank-based power meter). But in both cases, the ZPVB determined that riders supplied intentionally-modified power data and/or log files.

According to the detailed document for Berger, her supplied secondary power fit file showed a variance of “approx. 0%” when compared to her primary power file. This isn’t what you typically see when you record power from two different sources – but it is what you’d see if you record power from the same source, but in two places. So ZPVB judged that Berger likely connected both Zwift and her bike computer to the same power source.

And that could have been an honest mistake. But the document details how, over the course of the next days, Berger supplied a Zwift log.txt file from Berger’s Zwift device which didn’t match the corresponding file saved on Zwift’s cloud. Namely, the device list on Berger’s supplied log file had been modified to indicate that she had paired a smart trainer as her power source, instead of her Stages power meter as indicated in Zwift’s cloud version.

The document details other reasons for ZPVB’s findings in Berger’s case, but to summarize they judged that she:

Paired her Stages power meter instead of her smart trainer as the power source in Zwift
Recorded only the power from this power meter as both her primary and secondary power file
Attempted to modify the log.txt file to show that she had paired her smart trainer as the power source in Zwift

According to the detailed sanction document for Duncombe, she originally provided a backup power file which did not include her race, but only the first 90 seconds of her warmup. Again – this could be a perfectly honest mistake. But she later uploaded a different secondary power file to ZwiftPower, and this file showed values approximately 1% lower than the values from her trainer sent to Zwift.

An acceptable margin, except that this new secondary power file appeared to have been manipulated to look like it came from her Garmin, when in fact it appears to have come from Zwift itself.

The document details other reasons for ZPVB’s findings in Berger’s case, but to summarize they judged that she:

Did not properly record a secondary source of power from her power meter for the race
Attempted to supply a modified Zwift power file in the place of this secondary power file

What Are They Banned From?

Both riders will still be able to use Zwift whenever they’d like, and even race in “unofficial” Zwift races. They are banned (for 6 months) from taking part in official Zwift Cycling Esports events, which are typically invitation-only events for top-tier teams/riders.

Berger’s suspension has been back-dated to the point when the edited file was submitted to Zwift, and therefore runs from 18 August 2020 to 17 February 2021.

Duncombe’s suspension has been back-dated to the point when her edited file was submitted to Zwift, and therefore runs from 20 September 2020 to 19 March 2021.

Conclusion

Both of these cases give us a look into the sort of analysis Zwift’s Performance Verification Board does for its top-tier races. It’s no small job! But based on the evidence presented in the documents, it appears the sanctions are warranted.

As news of the sanctions has filtered into the Zwift racing community, one common response has been (as one Zwifter put it), “That’s all good, but I wish Zwift would put this kind of effort into policing community races.” And that’s a fair response, given how rampant sandbagging is in the category D, C, and B races happening every day.

While we should never expect Zwift to put manpower into manually checking power files for everyday community races, they could get rid of many of the sandbagging problems by implementing just a few controls in-game, such as forcing riders to join a particular category based on their historic power numbers. Perhaps opening up the (still beta) anti-sandbagging controls so race organizers can use them in events would also be a good step. Hopefully we’ll see progress here soon!

About Zwift’s Performance Verification Board

You can find the details of Zwift’s Cycling Esports Rules here, which explains that the Zwift Performance Verification Board is “responsible for ensuring the integrity of results of Zwift Cycling Esports events and series.” As such, it has “the power to update the results of events, and apply further sanctions to riders.”

The board is made up of a chair appointed by the head of Zwift Cycling Esports, a legal representative from Zwift, and a technical representative from Zwift. Zwift doesn’t disclose everyone who occupies these positions, but the sanction detail documents are signed by the chair, Dr. George Gilbert.