Former Olympic champion Michael Johnson has said he believes it is "unrealistic" to think athletics will ever be drug-free.
Johnson said Athletics is a microcosm of real life and in real life, there will always be people who cheat, the BBC reports.
Six Jamaicans, including former 100m world-record holder Asafa Powell and 2004 Olympic sprint relay champion Sherone Simpson, tested positive for banned substances earlier this year, the report added.
