Zwift bans two riders from racing for modifying data 

The Zwift Anti-Doping Agency has found two riders fabricated evidence and has issued suspensions from virtual races

Zwift has banned two riders for six months each for modifying their data after virtual races. 

The online training platform has issued suspensions for riders Lizi Duncombe and Shanni Berger, after the two riders were found to have falsified evidence after two separate women’s races on Zwift. 

Duncombe has denied tampering with data to Cycling Weekly, saying she is shocked by the process.

In the first case, published by Zwift on September 20, Shanni Berger had competed in the Off the MAAP Women’s Race #2 on August 17, finishing second in the event. 

The event required riders to use a trainer as their primary source of power data, not a power meter. 

Zwift data after the race showed that Berger had instead used a power meter, and had also appeared to pair the same power meter with both Zwift via Bluetooth and a secondary Garmin via ANT+ for “dual-recording” purposes.

This prompted Zwift to strip Berger of her result, but the decision was then protested by the riders team manager and team owner. 

Zwift’s software development team then investigated the files and found discrepancies in the power data, which suggested the files may have been modified after the event to look like the ride was recorded on a trainer, instead of a power meter. 

ZADA said the rider repeatedly denied any wrongdoing and claimed she did not have the technical capability to edit the files. 

Eventually Berger said “apologies for any misunderstanding” and added it’s “very possible that I made mistakes with the software due to human error.”

The Zwift Performance Verification Board ruled “beyond any reasonable doubt that the ride used their power meter as the primary source of power for the race, and therefore that the original judgement of annulling the result of the race for breaching the Technical requirements of the event should stand.”

The ruling added: “The board further consider that it is beyond reasonable doubt that the log.txt file provided by the rider as evidence of the pairing they used was edited after the event to change the primary power source. 

“The board consider that it is beyond reasonable doubt that this was a deliberate action to fabricate evidence to try to overturn the original decision by Zwift to annul the rider’s result in the race.”

Berger was banned for six months for “bringing the sport into disrepute” and “fabrication or modification of any data”.

The suspensions was backdated to the day when the edited file was submitted to Zwift, running from August 18, 2020, to February 17, 2021. 

In the second case, Duncombe was sanctioned by the Zwift Anti-Doping Agency (ZADA) on October 9 after inconsistencies were found in her data from the Zwift Racing League Women’s Qualifier #2 event on September 17, where she finished fourth.

All riders taking part in the event were required to record their power data from a power meter as well as their turbo trainer, known as “dual-recording.” 



Duncombe only recorded 90 seconds of data from her warm-up from a second device, and initially the Zwift Performance Verification board decided this was an inadvertent error, but without secondary evidence of her ride Duncombe was stripped of her result. 

She then submitted another power file as evidence of her performance, but further examination of the file by ZADA revealed a number of inconsistencies, which suggested Duncombe had resubmitted the same file but had changed the data to make it seem like a second power recording. 

Duncombe told Cycling Weekly: “From someone with a public track record in dual-power recordings for Zwift races, I’m shocked at how the situation has escalated to make it appear that I’d maliciously tampered with data with the dual power back up file when this isn’t the case and unfortunately ZADA has seen fit to serve me with six-month ban for the pro-am racing league.”

The statement from the Zwift Performance Verification Board said: “[We]  consider that it is beyond reasonable doubt that the rider did not correctly dual-record their ride, and therefore that the original judgement of annulling the result of the race for breaching the Technical requirements of the event should stand. 

“The board further consider that it is beyond reasonable doubt that the FIT file provided by the rider as evidence of them having dual-recorded their ride was edited after the event.

“The board consider that it is beyond reasonable doubt that this was a deliberate action to fabricate evidence to try to overturn the original decision by Zwift to annul the rider’s result in the race.”

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Despite denying any wrong doing, claiming she was a professional athlete who had nothing to gain from cheating and that she didn’t have the technical know-how to edit data, Duncombe was found to be in breach of Zwift Cycling Esports Rules and Regulations and has been banned from Zwift racing events for six months for “bringing the sport into disrepute” and “fabrication or modification of any data.” 

Her ban was back-dated to the day the edited file was submitted to Zwift, so her suspension runs from September 20, 2020 to March 19, 2021. 

Cycling Weekly has attempted to contact both riders for comment.

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