AP Photo

ON AUGUST 5th millions of people will watch the 100-metre final at the London Olympics. Many will wonder if anyone can repeat Usain Bolt’s feat in Berlin in 2009, when the Jamaican clocked 9.58 seconds, lopping 0.11 seconds—aeons in a sprint—off the previous world record, which he set at the 2008 Beijing games.

One person who thinks this unlikely is Mark Denny. Another 0.11 seconds would take the time below what Dr Denny, from Stanford University, reckons is the absolute limit of human athletic performance in the 100-metre dash.