I posted something similar in the "head case" thread, how there were a few reasons why a skater who is known to be excellent could have a bad day, with performance anxiety being only one of them.
So I was thinking, what are some other reasons given for someone's bad skate? I was thinking of a few examples. (Note: I have no idea how true these reasons are, they are just things I heard from various sources)
Johnny Weir--2006 Olympic LP--missed bus/too much partying at Olympic Village
Evan Lyscacek--2006 Olympic SP--stomach virus
Sasha--2006 Olympic LP--either nerves or had bad jump technique to begin with (heard that here)
Patrick Chan--2010 Olympics--recovering from an injury
Kurt Browning--had a back injury for one Olympics, at least, that cost him a medal
Jeremy 2010--probably nerves
Michelle 2002--weird coach situation
Rachael Flatt 2011-broken leg
Alissa Czisny 2012 (?)--never heard, but this was the worst of them. Was she injured?
Tonya--skate fell off/became untied (yeah, don't know if I believe it, either)
Debi 1988--she said she was "too calm" but coach thought the opposite
People who skated better than they usually did:
Sarah 2002--she said she got mad when she was "counted out."
Johnny 2010 LP--who knows, maybe he caught the bus and stopped partying this time
Nancy Kerrigan 1994--mad because she was hit on the knee
It seems that anger can be a great motivator for skating better than usual, but pressure to win, bad training habits and especially recovering from or trying to tolerate an injury is the reason for most unusually bad performances. This is all unscientific, of course.