Katrin Krabbe (left, top), double world champion, was caught with two colleagues trying to avoid a drug test. The three women were judged by the German Athletics Federation (DLV) to have manipulated urine samples which were found to be identical.
They were banned but appealed on a technicality, and were cleared because the DLV's constitution did not empower it to administer the test or impose a penalty. The three have now withdrawn from the Olympics on the grounds that the affair has disrupted their training.
Ben Johnson (left, centre), of Canada, who was stripped of the gold medal after breaking the world 100m record in the 1988 Seoul Olympics, is running again in Barcelona.
Butch Reynolds (left, bottom), the world record holder, was able to maintain a legal right to compete in the US Olympic trials. Reynolds obtained a place as first reserve on the US 4x400m relay squad. However, the IOC has said that he will be prevented from registering as an athlete in Barcelona.