Yes, I get this a lot when I play outdoor gigs in the summer in Texas. Even indoor gigs can cause it because of how hot and sweaty you get loading in. Sometimes I would get halfway through a set and would get a cramp on my left foot.I just started playing in a motown band that does large theater performances, and the last two shows we played 90 minutes nonstop. At about halfway through both of these shows one of my fingers would start to lock up or seize. When it happens the finger wants to just stick out, and if I don't do anything about it, it will cause a lot of pain. So what I end up doing is gripping my stick very tightly until it subsides. The problem is, once that finger is back to normal,a finger on the other hand will start doing the same thing. So again, I grip the stick tight until it goes away. But it's not over! Then a toe on one foot will do it, then one on the other foot. It's insane and very strange. I talked to the guitarist about it after the first show. He said it's happened to him before and what you need is lots of water and potassium. Well, last night's show I drank lots of water and ate a banana.
I think part of the problem is that I'm used to playing 45 minute sets, and because I'm in front of a much larger audience in a little nervous, so I may be holding my sticks a little tighter and playing a little harder.
Has anyone else experienced this and is so what can you do to prevent this?