I suffered from frozen shoulder and my dogs were getting super annoyed at how weak my throwing abilities had become.  I swear I even saw them roll their eyes at me when the tennis ball landed five feet from me.  The Chuckit Launcher solves that problem, because with minimal effort, you can get a tennis ball to sail across a field.  It's also great in that you never actually have to touch a slobberly ball, but can pick it up and throw it without ever having to touch it.