Yellow peril: Lance Armstrong leads the way

He wanted to see if the athletes could beat their personal best times after being subjected to intense yellow light.

Before going out on the track, they were made to wear large domes on their heads which acted as isolation chambers for their lights.

"One of the athletes rather worriedly asked if he would have to run with it on his head!" chuckled Dr Lewis.

Success

Once racing they wore yellow tinted sunglasses - and times were improved by up to a second.

Similar experiments using red and green lights were not as successful.

Olympic 400m finalist Donna Fraser said: "At first I was sceptical, but I ran a faster time than I thought I would...it could mean the difference between getting a medal or not."

Dr Lewis was not surprised by the success rate.

"Different colours produce different responses in the brain, which may in turn influence our mood," he stressed.

Norwich City: Well, there's always an exception to the rule

"Yellow is a very positive colour and is associated with happy things like the beach and sunshine.

"We all feel better when the sun comes out."

Which is all well and good, but how on earth are you supposed to stop the likes of Rivaldo, Steve Waugh and Lance Armstrong from winning everything in sight?

Simple - ask them to swap shirts before the action gets under way.