Got home late yesterday to give the tennis ball trick a go and disaster.... No tennis balls in the near vicinity, thought about using an apple, and then thought again !!! Eventually found a kids plastic oversized golf ball type thing. This was good for about 10 mins and then gave way under the immense strain ! It is painful and must look very strange, I made sure the the house was empty but I don't think my cat will ever look at me quite the same again..... Seems to have done the trick though, feeling a lot better today, maybe I will get a run in this week ?