Involuntary muscle contraction, also known as a SPASM (5 letters), is an uncontrolled and sudden contraction of a muscle. It can be caused by a variety of factors, including fatigue, dehydration, electrolyte imbalances, and even emotional stress. Spasms can range from mild to severe and can last anywhere from a few seconds to several minutes. Treatment for spasms usually involves stretching, massage, and rest.