Just a thought Mossdog. It might be worth considering doing a big block of basic leg strengthening work (weighted or body-weight). Squats, Swissball work etc while you're on a forced reduction in running. Come back stronger if not as run fit. Re: Wheezing Donkey and the knee thing. I had a similar experience with my knees improving with some cycling added to my training, as does Mrs tfg. My 'theory' was that the extra/different quad work improved the knee placement etc so stopping unwanted internal 'rubbing'. A simplified explanation.