I had this for a while when I was commuting on a fixed gear for a month or so with the saddle too high. I actually got bruising on the back of both knees, it was so bad. Just go easy on it; I doubt there is any permanent damage. It'll heal on it's own, even as you still ride. I still get it every so often if I'm doing a lot of climbing.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter