I might exaggerate, but I am almost convinced that within movement one of the most important things is how you master the split step. It is your very first reaction before starting to go towards the ball and it will determine the explosiveness of your movement.
The split step is simple and complex at the same time. Simple, as you just need to jump up slightly with both feet before heading off towards the ball. Complex, as it needs delicate timing in order to avoid to land too early or too late.
What is the main point about the split step? It will allow you to put the weight as quickly as possible on the relevant foot before making your first step. You jump off with both feet from the ordinary parallel position as you wait on the 'T', but you will land with one or the other foot in front of the other, depending where the ball was hit by your opponent.
Let's put it in order: 1) you have to jump just before your opponent hits the ball - this is the most delicate thing, to time the detachment from the ground well. 2) you want to be with both feet still in the air when you perceive/understand where your opponent has hit the ball. 3) depending on where the ball goes, you will land with your feet and weight accordingly.
Peter Nicol has always been extremely agile, but nobody employs the split step more intensively than Ramy Ashour; combined with his phenomenal reading of the game, this is what makes him so damn quick. After having watched the below video, you might want to have a further look on this one, showing Ramy in extreme slow motion with another legend, Jonathon Power.