I was DDR'ing for the first time this weekend. I do have a year of Stepmania experience, which is why I attempted a Heavy for fun very quickly. I was already worn out a little, so I was having a hard time, but at the end of the song I suddenly noticed how my right knee would not support me anymore, and within 10 minutes it hurt horribly and I couldn't walk without limping badly anymore.
Now (one day later), it's less or more okay, I can at least walk on it although it still stings when I hold my leg in certain angles. I was wondering, though, if anyone else experienced this. I never felt any pain during the game, only afterwards. Also, maybe noteworthy, I do tend to play a lot on my toes when the steps are fast. Shouldn't I? What did I do wrong? I have never had any knee problems in my entire life, although my ankles have always been rather weak.