Out to lunge.

Look at any top quality squash player and you will not see much running around the court. Instead they gallop and bounce and lunge. The disadvantage of running is that it is too upright, too straight-line, and involves too many steps. So instead of running around the court try to move in powerful side-steps and bounces. Don't sprint in a straight line for the ball - try to bounce up and down the middle section of the court and finish with a low lunge with your body down and your racquet stretched out across to the ball.

Have a look at some of the videos of professional players on youtube and see how they move around the court. How about this one?

http://www.youtube.com/watch?v=C884Y5MUwaU