Levaquin and half marathon

My experience with Levaquin is very similar to many of the other postings. I have had Levaquin twice, the first time for seven days that produced only mild joint and muscle soreness. The second time was supposed to be for 14-21 days for a severe sinus infection. The literature that came with the prescription did worry me a bit but I remembered reading the same information the first time I took it some six years previously. Well, about nine days into the prescription I was at the gym running on the treadmill, something I do a lot of. I had run in a Half Marathon about a week earlier and planned to just run an easy mile or two, get the blood flowing again. I was about a half mile into the run when it felt like someone stabbed me in the left achilles with an ice pick. I thought I was imagining it at first but I slowed up to see if it would go away. After another 10-15 seconds it now felt like my left achilles and lower calf muscle were going to explode. It may sound strange but that is the only way I can describe it. I have never felt anything like that in my life and I've had quite a few injuries to date. I limped home and for the next three weeks not only could I not even think about running, I couldn't even walk fast and had to shorten my normal walking stride. I went to see a doctor and he said it sounded like a slight rupture. Fortunately, the pain did subside and I resisted running for over three weeks just to be sure it had healed. I started running after that but very very slowly. However, even to this day, I can still feel a "tightness" in that area that was not there before the incident and does not exist on the right side. I had no idea that so many others were having similar or even more sever side affects from Levaquin until the weeks immediately following my incident. When I mentioned this to the doctor who prescribed it, he was very surprised and alarmed. Should he have known, well, probably, yes. However, now that he knows there is no excuse for not using caution for the next patient.