What is a charley horse?

A charley horse refers to a sudden, involuntary contraction or cramping of a muscle, often occurring in the legs. This painful tightening can cause a temporary impairment in muscle control, making movement difficult until the muscle relaxes. It commonly happens during physical activity or at rest, particularly in athletes or individuals who may have overexerted themselves or not stretched adequately. Understanding this term is essential in contexts like sports medicine, physical therapy, and general health discussions, as it pertains to muscle function and performance during activities.

The other options pertain to entirely different concepts; they do not relate to muscle cramping or impairments in muscle control.