It is interesting to observe how much distance players cover in a long rally. Here is an example. This is the last point between Sabine Lisicki and Jelena Jankovic. Jankovic ran 52.1 m/168.6 feet and Lisiki (44.6 m/147 feet). We can also observe that even top players do not always aim their balls close to the lines - but will keep their balls in a "safe zone." Of course, the fact that it is a match point cannot be ignored.