Itching to switch usually a rash move

From Michael Jordan to Usain Bolt, a select few elite athletes have attempted the switch to another top-level sport in a trait psychologists see as a "high need to achieve" coupled with filling a gulf in their lives.

Sprint king Bolt is the latest example, with the eight-time Olympic champion on a mission to become a professional soccer player.

But his abilities have been questioned, with the fitness levels and skill-sets needed for soccer very different from being the fastest man on earth.