Leg cramps are sudden, involuntary contractions of the muscles in the leg, often causing sharp pain. They can occur during physical activity, at rest, or while sleeping. Common causes include dehydration, overexertion, and imbalances in electrolytes like sodium, potassium, and calcium. These cramps typically last from a few seconds to several minutes and can affect anyone, though they are more common in older adults and athletes. Stretching the affected muscle and staying hydrated can help alleviate the discomfort. In some cases, persistent cramps may require medical evaluation to rule out underlying conditions.