Muscle spasm is a sudden, involuntary contraction of a muscle or a group of muscles which sometimes is accompanied by a sudden burst of pain, usually it is harmless and ceases after a few minutes. Spasmodic muscle contraction may also be due to a large number of medical conditions, including the dystonia. In very severe cases, the spasm can induce muscular contractions that are more forceful than the sufferer could generate under normal circumstances.