Where in the world did we get the term, "charlie horse"?

Question

I know what it means. I wake up with them in my legs sometimes. But who the heck is Charlie and what does his horse have to do with my muscles cramping up? English is a strange, fun language sometimes.... = )

Answer 1

Charley horse

A charley horse is a North American term for a painful contusion of the quadriceps muscle of the anterior thigh that commonly results in a muscular hematoma and sometimes several weeks of pain and disability.1,2 It often occurs in sports when an athlete is struck by an opponent's knee, in a manner not unlike the kick of a horse, perhaps the reason for its name. In the UK, such an injury is known as a Dead Leg, corky, or corkie.
In recent decades the term has also been used to describe painful leg cramps, which may occur in the thigh, arch of the foot, toes, calf muscle, or quadriceps. Unlike leg cramps, however, a charley horse can occur when the muscle in question is not being used, such as while lying in bed.

The term may date back to American baseball slang of the 1880s, possibly from the pitcher Charley "Old Hoss" Radbourne who is said to have suffered from cramps. Another story mentions a horse named Charley that used to work at Comiskey Park, the Chicago White Sox' ballpark in Chicago. In those days, an old, perhaps lame, retired horse was often called "Charley."