A friend and I were playing this weekend, and behind us on the set of courts were a husband and wife working with a ball machine. For nearly two hours they took turns hitting groundstrokes, with the husband being the type who gives non-stop advice to his wife. The funny thing about it is that they each had nearly identical strokes, with the wife evidently trying to copy her husband. But their strokes were terrible! Wristy, all arm, with no body rotation or legs in the shot. I think working with a ball machine can be valuable if you're trying to groove good strokes. But why would someone spend the money on a ball machine in order to create muscle memory of a terrible stroke? After all the balls they hit, that muscle memory would be incredibly hard to undo. I wanted to shake them by the neck and tell them to save their money on the ball machine, and take some lessons instead if they wanted to improve. I just don't understand why so many people who are willing to spend money and time on tennis don't do the sensible thing and get some instruction. It's not like tennis instruction is difficult to find in Atlanta.