Muscle cramps

There is a condition called tetany. It might be worth looking into if the symptoms sound anything like what your daughter is describing.

 

Thank you. Not quite the same but perhaps some overlapping.
Calcium plays so many roles it's likely to be part of it.

 

I was getting bad muscle cramps at one time. Coincidently, a relative was taking up jogging at the time and spoke about having to warm muscles up before exercising. I thought that because I did not move very much when I did move it was like a normal person going straight from walking to running without the warm up exercises.

Nowadays, I try not to make sudden movements so that the muscle fibres get a chance to start working and get lined up with the blood flowing and the linkages changing gradually.

I may have the science all wrong, but I get much less cramp and if I feel it starting I can usually fend it off. A slow stretch doesn't cause the cramp I always used to get either.

Permanently spasmed muscles sounds more like a chemical problem though. There are many genetic diseases that affect mineral movement across membranes but they are often missed.

 

If I do a repetitive motion, my muscles may cramp and remain in that position for a few seconds.

Of course they tire easily, and burn with exertion.
They burn even more with Post Exertional Malaise.