I went through a stage of those - I would wake up screaming!!

Anyway, I realised that a lot of the time, they were caused by pointing my toes/foot in my sleep (eg. if the covers got stuck on my foot). So, firstly, I used pillows at the end of the bed (under the covers) to stop the covers getting stuck on my foot. Then, when I had a cramp, I would point my foot upwards (towards my knees), to stretch it out.

I also sleep with a pillow between my legs - this helps with the aches in my thighs, but not the cramps in my calves.

Finally, I have heard that increasing salt is supposed to reduce your susceptibility to cramping - but I didn't try this.

HTH

Ez.