A fine line exists between becoming a champion in professional sport and breaking the rules.
This year has seen a succession of fallen heroes and miscreants outed by scientists running anti-doping teams.
They range from the Russian athletic team barred from the Brazil Olympics to tennis star Maria Sharapova falling into disgrace.
World champion boxer Tyson Fury has also been stripped of his belts amid accusations of taking a banned substance, thought to be cocaine.
The latest sports superhero to fall victim to speculation about doping is Olympic and world champion cyclist Sir Bradley Wiggins.
Investigation under way
Wiggins admits taking banned steroids to tackle a medical condition before winning the 2012 Tour de France.
He is also accused of taking the steroid before other races.
Wiggins, along with doctors and managers from his Team Sky argue that he declared the medical condition and taking the steroids.
Other riders and teams say the drug gave him an unfair advantage as steroids can enhance performance.
The allegations against Wiggins remain unproven and an inquiry is underway.
“British Cycling can confirm there is an ongoing investigation with which we are cooperating fully. We are unable to comment further at this stage,” said a British Cycling spokesman.
What are banned substances?
Either way, a wide range of sports seem to be riddled with accusations, excuses and counter allegations of doping.
With prizes of millions of pounds at stake for winning a world title, no one should be surprised that athletes are tempted to take illicit drugs to boost their chances of grabbing a slice of the action.
Doping generally covers the taking of five types of stimulants and hormones which meet two of three conditions:
- Enhance performance
- Threaten an athlete’s health
- Break the spirit of sportsmanship
Foul play is not more of an issue now than before, except advances in medicine make many drugs a lot easier to detect in an athlete’s body.
The first Olympic tests were introduced in 1968.
The World Anti-Doping Agency (WADA) was introduced in 1999 to oversee drug testing of athletes in all major sports.
Besides Wiggins, Fury and Sharapova, other high profile athletes stripped of titles include Canadian Olympic sprinter Ben Johnson and world champion cyclist Lance Armstrong.