Being at the centre of defence puts you up against the opposition's strikers, which can be a real challenge.
You will have to be a good tackler and strong in the air.
But the ability to read the game by spotting where the likely danger will come from is the biggest asset.
Central defenders need to be very committed and focused on their role.
John Terry provides defensive solidity for Chelsea and England
If you let the opposition striker get in behind you then it can easily result in a goal against your side.
You cannot relax for one second - there is danger on the football field from every possible angle.
Where are the strikers going? Which midfielders are bursting through?
And when your keeper's got the ball, should you make yourself available for the easy pass?