What is mechanical doping? Tour de France cyclists accused of technological fraud – all you need to know
Latest cycling allegations to hit the sport come from a US TV show featuring the so-called inventor of mechanical doping Istvan 'Stefano' Varjas
CYCLING has had its reputation dragged through the gutter in recent years.
And 'mechanical doping' is the the latest scandal to hit the sport.
Here SunSport tells you what you need to know about it...
What is mechanical doping?
The term is slightly nonsensical given that no drugs are administered.
But the idea is that riders attempt to gain an advantage over their rivals by having small motors installed into their bikes.
How is mechanical doping achieved?
The idea is that riders put the motors inside a seat tube with a gear that powers the bottom bracket axle, meaning that the pedals can go round without human force.
Clearly the motors need a source of energy and that comes in the form of a battery pack which can be stored alongside the motor.
The motors can then be turned on and off at the push of a small button.
The rider still needs to put plenty of effort in to gain any kind of race-winning advantage, but the extra boost could be the difference between victory and defeat in a close finish.
What are the latest mechanical doping allegations?
US TV show '60 minutes' has aired an interview with Istvan 'Stefano' Varjas, who is widely regarded as the inventor of mechanical doping technology.
He reaffirmed his belief that pro cyclists are using the motors - but said he could not name individual riders.
The Hungarian also claimed that the technology has existed since 1998 and that he had been paid $2million for an exclusive deal by one buyer.
The terms of that agreement apparently meant that he could not develop of talk about it, with the CBS show stating he was jailed over that period for a "substantial" unpaid tax bill.
Jean-Pierre Verdy, a former chief for French anti-doping, also spoke to the programme and revealed that he believes the Tour de France would have been tainted by the form of cheating.
Verdy said: "It's been the last three to four years when I was told about the use of the motors and in 2014, they told me there are motors.
"They told me, there's a problem. By 2015, everyone was complaining and I said, 'Something's got to be done.'"
Who has been found guilty of mechanical doping?
Femke Van den Driessche is the only athlete to have been sanctioned so far.
The Belgian was charged after an incident at the 2016 UCI Cyclo-cross World Championships.
In April 2016 she was banned from the sport for six years from October 11, 2015 with all her results marked as disqualifications over that period.
What is being done to stop mechanical doping?
A lot of checks and tests with fines and minimum bans of six months for anyone found guilty.
UCI, cycling's governing body, has claimed that they are using new devices to detect motors by revealing the presence of electrical circuitry and batteries in bikes where they should not have them.
Thermal cameras were also used at the 2016 Tour de France.
The UCI claims mechanical doping 10,000 checks were carried out in 2016.