I am the king of hand cramp! I dont usually suffer during natural, other than the usual arm pump, it's more on street. I'm fine unless I cram loads of Redbull into my system and go mad for about 30 mins, then my hands 'lock up', this is meant literally, I have to beat my hands off the bar and prise my fingers open, it's messed up. No idea what causes it, but it's a pain in the arse.