what causes bad muscle cramps
Overuse of a muscle, dehydration, muscle strain or simply holding a position for a prolonged period can cause a muscle cramp. In many cases, however, the cause isn't known. Although most muscle cramps are harmless, some may be related to an underlying medical condition, such as: Inadequate blood supply.
Muscle spasms and cramps. Cramps are caused by muscle spasms - involuntary contractions of one or more muscles. They can be painful but are usually harmless. They come on without warning and almost everyone will experience them at one time or another.