Run-up, Approach

Almost all bowlers need a run up before delivering the ball, to bring them up to the required speed and into the rhythm at which they are comfortable to bowl it.

The run-up can vary from two or three strides up to thirty or so, depending on the speed at which the bowler bowls. Generally speaking, the longer the run-up, the quicker the delivery is likely to be.
The former Gloucestershire player Bryan 'Bomber' Wells had a two stride run-up at the start of his playing career. When told that he would have to do a lot of bowling for the County he replied that he had better shorten his run-up. He did - to just one stride!
The run-up is also the name for that area of the ground beyond the wickets at each end on which the bowlers run up to bowl.