Re: Muscle cramps in legs while asleep
An old trainer during my track days suggested charleyhorses were partially due to a lack of potassium. Try some bananas.
On a related note, this happened to me once about 15 years ago. I was just sleeping like you when it hit me. I woke up screaming and my heard me from upstairs and came down to help me stretch it out. I still have vivid memories of the pain. Not fun.
Good luck with it.