A charley horse is basically a painful leg cramp, or when all the muscles in your
calf seize up.
Someone
kneeing you on the side of your leg can yell "charley horse!". In fact, that's how I I first heard of this term, back when I was in first grade.
Goneaway says that the late stages of his/her untreated diabetes gave some of the worst charley horses ever.
Potassium deficiencies can also cause charlie horses.
Charley horses can also be caused by dehydration or overexhaustion during exercise, restricted blood flow, and nerve irritation. You can prevent them by stretching out before exercise, keeping warm at night and drinking plenty of water (According to
LaggedyAnne)