We’ve all heard that you should bend at the knees and not at the waist when hitting ground strokes. To learn to bend at your knees rather than at your waist, try watching the bottom half of the ball as it moves toward you. When you’re looking for the lower half of the ball, you’ll find that you naturally lower your body by bending your knees. You also may find that you see the ball more clearly. This will help you set up for your shot and properly distribute your weight, so your strokes should gain some power, too.