Video report by ITV News Correspondent Ben Chapman
Scientists searching for the answer to athletic prowess have discovered their subjects have been sitting on the answer the entire time.
Researchers now believe it is the Gluteus Maximus - the muscles that make up the bottom - that make the ideal sprinter.
A Loughborough University team found runners with bigger backsides ran up to 44% faster than their smaller cheeked counterparts.
The Gluteus Maximus muscles in the fastest athletes were found to be far bigger - up to two kilograms on each side - with scans of participants' behinds showing the difference in density.
The team hope the findings could help revolutionise training - with new emphasis on the areas of the body to work.
Professor Jonathan Folland, an expert in neuromuscular performance, described the findings as "remarkable"."This is surprising because sprinting is thought to be influenced by many factors – technique, psychology, nutrition, anatomy of other structures – so to find a single muscle that alone seems so important, explaining nearly half the variability, is remarkable."
He added: "The logical implication is that with a larger gluteus maximus the runner will be able to generate more power and therefore greater sprint speed."