Successful baseball fielding requires developing a quick first step and the ability to change direction and move laterally with speed and control. The most skilled defensive players are not always those that run the fastest, but those that also have a quick reaction time, a quick first step, and are able to get a good read on the ball. Getting to the ball faster enables a player to be in a better position to make a strong and accurate throw. For a player to get to the ball faster, they must train their legs and core to increase strength for a quicker reaction time. There are a number of different exercises and training tools that can be used to improve these muscles.
The ability to change direction is huge in the game of baseball. A player must be able to pricisely change direction to have the best chance of making a difficult play. Change of direction is also important for tracking down a ball and transitioning into throwing. Aside from the change of directions, players must also have the ability to move laterally in a quick and effective manner to be successful in fielding. It does a player no good to be the fastest guy on the field if he can't move with precision and control.