Thus, a positive feedback develops so that a small amount of initial irritation causes more and more contraction until a fullblown muscle cramp ensues. Reciprocal inhibition of the muscle can sometimes relieve the cramp. That is, if a person purposefully contracts the muscle on the side of the joint opposite the cramped muscle while at the same time using the other hand or foot to prevent movement of the joint, the reciprocal inhibition that occurs in the cramped muscle can at times relieve the cramp. There is little knowledge of the exact nature of leg cramps and as an effect of this there is no primary cure. I will mention a few of which magnesium have been of help for me.
Cramps is common with hypoparathyroidism.
Magnesium inhibit calcium entry into nerve terminal. Severe magnesium depletion leads to tonic-clonic convulsions. In obstetrics magnesium sulfate has an anticonvulsive, sedative and blood pressure lowering effect due to its blockade of the neuromuscular transmission. Magnesium sulfate has no place in the therapy of leg cramps. I only mention this practice in obstetrics to illustrate the cramp lessening effect of magnesium.