The Commonwealth games reminds me to say something I have been considering for a long time.
Sprinting events have a long history of performers whose achievements suddenly rise to extreme heights, either (or both) in terms of their own career or global performance standards. In almost all cases of such steep rise, artificial stimulants were involved. The performances of the adored Usain Bolt, who is the biggest draw in contemporary athletics, rose with awesome steepness. See http://engineeringsport.co.uk/2012/06/21/how-fast-is-usain-bolt/.
Five Jamaican athletes have already tested positive for drugs:
The world of athletics has a huge investment is Bolt being “clean”. If, to use a cliché, I were a betting man (I have never laid a bet on anything), I would not put any money any top current sprinter running below 9.80 seconds not being eventually exposed as a drug cheat, using techniques that are currently difficult to detect. I hope that this is not the case. Bolt is properly regarded by myself and the world at large as “clean” until proved otherwise. But the history of athletics, and its willingness to welcome back those convicted, does not encourage me to be optimistic that new revelations will not emerge.