Did you notice that most of the track athletes were wearing bright green shoes?
Well all the shoes are worn by Nike athletes making those bright green shoes Nikes,
Known as 'Volt', the shoes are striking against the red track in London. Nike says that out of all the colors on the rainbow, the human eye is most sensitive to the yellow/green zone. That means the Nike shoes the Olympians are wearing reflect more light than nearly anything on the field. The shoes are there to be bright and bold so you look at them... and want to buy them. Basically, brighter yellow green shoes are better at attracting attention, even if everyone else is wearing the same bright yellow green shoes.