what causes muscle contractions in legs?
Causes of Muscle contractions that are rare. The offical US government definition of a rare disease is one that affects 200,000 people or less. The following causes of Muscle contractions appear in the population at a rate of less than 200,000 people per year in the USA: 1  Alpers Syndrome-involuntary muscle contraction. 2  Fahr's Syndrome-athetosis. 3  Ramsay Hunt syndrome Type II-involuntary muscle contraction.