Two of the world’s fastest sprinters, Tyson Gay and Asafa Powell, have tested positive for a banned substance, leaving the athletics world “shocked”.

Did they cheat or was it an accident? FactCheck can’t provide that verdict – but as disappointment ripples across the global arena, we assess the trends in sports doping.

Biggest offenders

The number of failed drug tests in athletics is on the rise. Statistics from the World Anti-Doping Agency show that 1.15 per cent of tests taken in the year of the Athens 2004 Olympics had “adverse findings”.  By 2010, that figure was up to 1.75 per cent.

In the UK, five athletes are currently banned from competing after failing drugs tests. Athletics is the fourth worst-offending sport – with a total of nine athletes banned since records began in 2009.

The most bans received in the UK however are for rugby league players – with 15 banned since 2009, followed by rugby union players, with 12 banned. The majority of the failings were down to the presence of the stimulant methylhexaneamine in tests.

Next up are professional boxers, with 10 banned, then come the athletes and finally weightlifters take the number five spot with eight bans.

On a global scale it is the weightlifters who take the top spot for failed drugs tests – with 2.97 per cent of tests in 2010 showing “adverse findings”.

Among the drugs that showed up in the tests were cannabis, the performance-enhancing drug stanozolol, the hormone human chorionic gonadotrophin (hCG), the stimulant benzylpiperazine and the steroid metenolone.

Most improved

Given the spate of recent scandals, it may come as no surprise that cycling is ranked as the second highest offending sport.

But it is also the sport that has seen the most improvement since 2004. In the year of the Athens Olympics, 4.6 per cent of cyclists tested failed their drugs tests. In 2010 that figure was down to 2.86 per cent.

There have been small improvements in other sports – namely shooting, tennis, badminton and boxing.

Cleanest Olympians

As the graphic above shows, badminton players are the cleanest sports stars with just 0.4 per cent failing their tests in 2010 (five players). The next cleanest sports are rowing, shooting, tennis and modern pentathlon.

Fastest rising offenders

On the flip side, “adverse findings” are on the rise  in other sports.

Hockey players have deteriorated the most – with failed tests up from just 0.6 per cent in 2004 to 2.51 per cent in 2010.

Failed tests are up in sailing, from 0.99 per cent to 2.14 per cent, and in table tennis – from 1.05 to 1.93 per cent.

Meanwhile, gymnastics has suffered a climb from 0.39 per cent to 1.24 per cent and finally the number of equestrian competitors failing their drugs tests has jumped from 1.53 per cent to 2.35 per cent.

Outsiders

Amid the failed tests, a few lone offenders crop up in otherwise seemingly “clean” sports.

In the UK, a lone cricketer has been banned since 2009 – Abdur Rehman was banned last year for three months after cannabis showed up in a sample test.

Another sportsman falling foul to cannabis is wheelchair tennis competitor Anthony Carter, who was banned for three months.

A single amateur boxer, Ryan Llewellyn, was banned for a year after the stimulant methylhexaneamine showed up in a test.

By Emma Thelwell