Headline 6th December 2008: Misplaced enzyme is to blame for quick fatigue after mild exercise in muscular dystrophy. May play role in chronic fatigue syndrome & MS as well. I had a muscle biopsy in the 90's to find the cause of my severe muscle fatigue. They found a missing enzyme, then changed their minds and said it was there after all. This new research makes me think that in the case of my biopsy, the enzyme was actually 'misplaced'. It makes sense if you read the research article on ProHealth [highlighted above]. My belief is that restriction of blood to the muscles causes both the pain and the fatigue. I just hope they can come up with a 'viagra-type' drug that is both effective and doesn't have nasty side effects.