Concentration
This is no doubt the most taxing position to play in cricket, demanding a higher standard of stamina, concentration and certainty than almost anyone on the field. It has been said in fact that wicket-keepers are born, not made, because the assessment of the ball in flight - which is
often lost to the wicket-keeper - is a skill not many can master.
The wicket-keeper watches every delivery and in his mind takes it. The speed of diving for a catch or stumping demands the highest degree of athletism, fitness, mobility and speed which few have.
However, he can only do what the bowler and conditions of weather allow him to do. Today the standard of wicket-keeping is high in respect to swing and keeping to pace.
The depth of the wicket-keeper's position is not necassarily an indication of the bowler's pace. He will stand back to a very fast bowler as he is able to cover adequately a large potential catching area, for convenience to a fast-medium bowler or on a lifting or uneven-paced wicket.