Four-time Olympic champion sprinter Michael Johnson believes that athletics will never be rid of drug cheats.
The sport has been plagued by a number of high-profile doping issues, and while there are strict testing rules within athletics, Johnson believes that some athletes will always try to cheat.
"Athletics has a zero-tolerance policy with drugs and, in a way, we have kind of suffered because of that," Johnson said at a Doha GOALS Forum. "Since we control it more than most sports, we have more scandals and more people caught.
"Despite that, you are never going to have a situation where no-one cheats. Athletics is a microcosm of real life and in real life you will always have people who cheat. It's unrealistic to expect athletics to be a drug free sport."