Sunday 1 May 2016 21:24, UK
Simon Yates is potentially facing a suspension after testing positive for the asthma drug terbutaline at the Paris-Nice stage race in March.
His Orica-GreenEdge team insist they are to blame, having failed to apply for a therapeutic use exemption (TUE).
Here, we look at the case more closely…
What is terbutaline?
Terbutaline belongs to a group of drugs known as β2-agonists, which are primarily used to treat asthma and other pulmonary illnesses.
Asthma is the inflammation or constriction of the airways, and the β2-agonists work by relaxing muscles to aid breathing.
All but four β2-agonists are banned by the World Anti-Doping Agency. They are: salbutamol, salmeterol, formoterol and terbutaline. However, crucially, terbutaline requires a TUE before it can be used by athletes.
Why did Yates take it?
Yates has "documented asthma problems" and took terbutaline through an inhaler, according to Orica-GreenEdge. But why he was given terbutaline instead of one of the permitted β2-agonists has not yet been officially confirmed by the rider or the team.
It has been reported in the British media that he usually uses a permitted drug but was given terbutaline for the first time after suffering an acute episode.
Does terbutaline improve athletic performance?
The first thing to point out is that it not yet clear how much terbutaline was in Yates' system, and this is relevant because the amount taken has a big impact on potential athletic benefits.
When taken in supratherapeutic doses - more than what would be used to treat a medical condition - various studies have found terbutaline improves some areas of performance.
One study published in the European Respiratory Journal in 2013 found that supratherapeutic doses increased muscle strength and power but decreased endurance, while a second published in the European Journal of Applied Physiology in 2014 concluded that "high-dose inhaled terbutaline elicits a systemic response that enhances muscle strength and sprint performance".
When taken in therapeutic doses - no more than to treat a medical condition - current evidence suggests there is no performance gain.
In an interview with Cycling Weekly, Dr John Dickinson, the head of the Respiratory Clinic and senior lecturer at the University of Kent, said: "The dosages required [to improve athletic performance] are above therapeutic levels. An athlete would have to be either using the medication wrongly, contrary to advice, or in a deliberate attempt to enhance performance."
In an article he wrote in specific relation to Yates' failed test, Dr Dickinson added: "An athlete using terbutaline as prescribed therapeutically is not likely to benefit from a performance enhancement in their sprinting."
What happens next?
Yates is currently free to race due to the fact that, under International Cycling Union (UCI) anti-doping rules, terbutaline is designated as a "specified substance" and a provisional ban is therefore not required. However, he is currently out of action with a knee injury.
Orica-GreenEdge say they are conducting "a full evaluation … of the documentation, statements and evidence" surrounding Yates' failed test, all of which will be submitted to the UCI. They do not want to comment further to ensure that the process is unprejudiced.
Fundamentally, they will have to explain why Yates was using terbutaline without a TUE and convince the UCI that there was no performance gain, and no intention to gain.
If they succeed, Yates could be let off, but if they fail, he faces a ban lasting anywhere between several months and several years.
Several months appears to be the most likely sanction given that the Norwegian cyclist Vegard Robinson Bugge received a four-month ban for using terbutaline last year.
