I don't take any calcium supplements in my old age, I get enough from diet and too much calcium, especially a form that don't absorb well in the system like calcium carbonate, can end up blocking the arteries and lead to strokes, etc. My father in law took oyster shell calcium daily for years and ended up with a major stroke that half paralyzed him. Docs said his main carotid artery was 99% blocked with calcification. Since then I started taking vitamin k2 also, to help keep the calcium in the bones and out of the arteries. Also, calcium makes the muscles contract as Doug mentioned.
I was getting a lot of those toe cramps several years ago when I was going to a gym and doing Zumba classes a couple of times a week. I really got into the dancing part and enjoyed it a lot, but a lot of the moves were jumping, up on toes, etc.
That was the first time I experienced any toe cramps, and was amazed at how my toes, usually the last 3 small ones, would uncontrollably curl on me. I always have Magnesium Oil on hand for leg cramps, so rubbing that in gave quick relief from the pain and relaxed the toes so they went back to normal again.
Then I started increasing my daily supplement of Magnesium Citrate from 150mg to 300mg daily. Been a long time since I had a toe cramp, but if I'm crouched on the floor cleaning out low cabinets or something, I'll get a foot cramp in the arch, used to have Plantar Fasciitis problems a lot when I worked on my feet all day, so maybe that's related. But haven't had problems with that either.
Falcon had good advice to eat a banana for the potassium. I think these cramps are just from muscles contracting and stress related.