Well there are some. Check out Petrucci´s Rock Discipline video where he goes through lot´s of strech stuff types. But when I asked a doc for advice he told me that I should avoid to do those streches ´cause thety aren´t good for the hand. So now basiccly I make sure to be warm in my hands, to get a good blood flow (just rub them against eachother) and start with some easy riffs/solos and you should be ok.