Robert Harting (Getty Images)
Berlin - Germany's out-spoken Olympic discus champion Robert Harting has criticised sprint superstar Usain Bolt for not speaking out more in the fight to clean up athletics.
The 29-year-old Bolt will attempt to win the 100m, 200m and 4x100m relay titles for a third straight Games before bidding farewell from the Olympic stage in Rio.
Bolt's retirement will be another blow to a sport suffering the fall-out from a Russian state-sponsored doping scandal and corruption allegations against the former leadership of the International Association of Athletics Federations (IAAF).
Harting had hard words last month for IOC president Thomas Bach, who he branded "part of the doping system", over the International Olympic Committee's (IOC) decision not to blanket ban Russian sportsmen and women in Rio.
And the German says he is suspicious of Bolt for not taking a harder stance in the fight against doping.
"I would ask him why he does not go on the offensive, in any way, on the subject of doping," Harting told magazine Sport Bild.
"The best known athlete in the world must join the current discussions and fight for a clean sport, especially since a lot of sprinters have tested positive and he has also been accused on a massive scale.
"The fact he stays out of it, gives a lot of food for thought."
Speaking in Rio, ahead of the start of the athletics meet on Friday, Bolt said he believes his sport has turned the corner in the fight to cleanse itself.
"We're weeding out the bad ones. I personally think we're on the right track," said the Jamaican.