In 2009 I became the fastest man in the world after I clocked 9.58 seconds in the 100 metres at the World Track and Field Championships in Berlin. That was a great achievement for me as a young Jamaican.

But the science of track and field suggests that the times should get even quicker. What will the winning time be at the 2036 Olympic games? Scientists have made several attempts to calculate, and by extension predict, how fast humans can go. Perhaps in a quarter of a century man could be running 100 metres in 9.00 seconds. Incredible!

Well before then, my wish for athletics would be for substance-abuse to be totally eliminated, so athletes can have an opportunity to compete fairly.