As often as athletes talk about being "in the zone," that's typically taken as a metaphor or a vague feeling.
Actually, it might be a scientific phenomenon. In a recent study, some participants were supposed to touch a screen when lights came on, while others just watched. The first group said there was more time between the lights than the second.
In other words, when asked to perform an action, time seemed to slow down for participants.
See the story at Discovery News.