When digging a ball hit down the line it is important to stay on the line. Doing so will allow you the proper angles to make an effective dig.
The Bad Habit
Many players have the tendency to move into the court while on defense. A few feet inside the court may not affect you much when digging a ball hit across court. However, a few feet can be disastrous when digging a ball hit down the line.
By moving inside you force yourself to reach for the ball. Reaching to the side for the ball will make it very difficult to get the ball to the setter. It is more likely that you will pass the ball towards the bleachers, forcing your setter to chase it down.
Also, it is important to note that if you are in the wrong position you simply will not have enough time to adjust to the correct position. The ball is coming too quickly and it is important to minimize movement while digging.
The Solution
Make a conscious effort to remember your position on the court. Stay aware of your surroundings and if you find yourself creeping inward, reposition yourself. In the beginning (and for most of your career, in fact) it will be effective to keep your outside foot directly on the line.
