DDR Freak often has injury discussions related to Dance Dance Revolution and Pump It Up, and has even done polls. Here's a sample of complaints:
stepped off the pad and twisted my ankle.Like any other sport, videogame exercise can hurt. Know your limitations. Wear sensible gear, warm up a little, do an easy song or two to warm up. Oh, and if you don't already do knee drops, don't start now.
Slipped playing doubles (someone drank water while playing before me) and hit my head on the bar
cutting my toe open on the first time i beat paranoia survivor
I had an asthma attack
My friend has a heart disease and only discovered it after playing a few games of DDR - Her heart was racing and she had to be rushed to the hospital.
Dislocated my sholder while playing MaxX Unlimited. In the arcade I had one arm on the bar I had to do a few steps very fast. The arm that was not on the bar got jurked by moving so fast. I walked off the stage and left...in pain.
blisters, sprained ankle, almost fainted (literally) broke off my left big toe-nail.
[regarding the toenail quote:]
Wow, that happend to me, too! And i'll never DDR in 2-inch platforms again...
My left big toenail fell off after playing ~6 hours a day on a cruise ship last summer.
my friend went for a double knee drop and smacked his shins on the sides of the pad.
My knees really hurt from playing DDR.
I have a 3/4 inch scar accross my right knee from sliding into the metal at the back of one center down arrows at the end of Foxy Lady... The metal doesn't round down around the outer edge.
Probably a compound injury is mine. Under my knee caps on both legs I have calcified spots which have happened from knee dropping during freestyles. Yeah...I don't feel anything in those spots anymore. Other than that anything else have been screw corner-piece bruises/cuts in my knees and palms from misplaced hands and other stupidity (like the end of LIADZ Remix Nightmare).
I have suffered with many bruised knees to where I also don't feel them anymore and also, I have bent my fingers wrong coming down to hit the pad with my hands a few times. Recently I had a full combo on Soca Make Yu Ram Ram on nightmare and during the spin I slipped and busted my knee.... ouch...
Most of the injuries I usually get while playing are hurt fingers or busted knees... I get over it...
I nearly broke my own kneecaps once coming to an unexpected stop during R3 Heavy Doubles - I'm not quite sure what exactly I did to them, but they made this unpleasant cracking noise and were essentially immobile for several days.
I usually go with a few toe touch stetches before play, lol, that doesn't usually work for most of the songs I play....well, i have bruised my leg and now it is hard for me to even walk right now, I still play PIU though!
(Sources: mostly DDR Freak and Indy DDR.)