Cramp is a word applied to muscular contractions of an irregular kind, in a somewhat variable way.
(1) In its common use, it denotes an involuntary and painful contraction of a voluntary muscle or group of muscles. It is most apt to occur when a muscle has been fatigued; though any muscle may be affected, those of the calves most often suffer. It is especially common in pregnant women and persons of a gouty diathesis, and is a prominent feature in some diseases, especially cholera. There is no specific for preventing it; each case must be treated on its merits. The contraction and accompanying pain is usually cut short if the affected muscle be stretched—e.g. in the case of the calf-muscles, the knee must be straightened and the foot bent up as far as possible towards the front of the leg, to lengthen the affected muscles to the utmost, and similarly with other cases.
(2) Writer's Cramp is the commonest and best known of a group of diseases called trade spasms. The person affected can use his fingers for any purpose, even the most delicate manipulations, so long as he does not attempt to write; but whenever he does so, the muscles refuse to obey his will, and the pen either drops from his hand or executes spasmodic purposeless movements. Similar conditions may occur in telegraphists and pianists—in fact, in any case where frequent and continued use of particular muscular actions is necessary. These distressing and troublesome affections have recently been cured in some cases by means of Massage (q.v.) and systematic gymnastic exercises of the affected parts.
(3) Bather's Cramp.—A good swimmer, while bathing, is seen to throw up his arms, perhaps is heard to cry out once, and then sinks to rise no more. It is said that 'bather's cramp' has been the cause of his death. This phrase, however, is merely an apology for ignorance: what has happened, and whether it is the same in all apparently similar cases is as yet quite uncertain. Cramp, in the ordinary sense, of one or more limbs, though very embarrassing and alarming, would not be so disastrous to a practised swimmer as to make him sink without a struggle; and, though common in bathers, cannot be accepted as the cause of all the fatal accidents like that described above. Of other theories advanced, the most probable is that sudden failure of the heart's action, a partial or total faint, is the cause of the calamity, at least in very many cases. A sudden plunge into cold water by itself causes some strain upon the heart; and swimming, about the most severe of all forms of exercise, increases its work very greatly—sometimes, it is easy to believe, beyond safe limits. The recorded experience of some who have narrowly escaped death from this cause makes it appear extremely probable that it is the real explanation of at least some of these sad accidents. No one when out of practice should attempt a long swim in cold water; and persons with weak hearts should be especially careful to avoid fatiguing themselves when bathing.