Charley horse

Charley horse is a colloquial term typically used to refer to a muscle cramp or stiffness,^[5] particularly those of the calf, foot, leg,^[6] or more rarely, the arm.^[7] Some may use the term interchangeably with the term dead leg or thigh contusion, referring to a contusion caused by a physical blow to the leg or thigh.^[8]

Charley horse
Other names	Charley,[1] Charley-horse,[2] charlie horse, leg cramp
Specialty	Physiatry, Sports medicine, General practice, Primary care[3][4]

The term came into use in the setting of baseball in the United States in the 1880s,^[9] though its exact origin is uncertain.^[10]

Etymology

The first known written use of the term was in 1886 in the Boston Globe.^[11][12] The origination has been attributed to two baseball players, Jack Glasscock and Joe Quest.^[13] However, its exact origins are unknown.^[14]