What Is the Difference Between a Muscle Spasm & Muscle Cramp?

Updated February 21, 2017

Muscle spasms and cramps occur when a voluntary muscle contracts on it own. The difference is the intensity of the contraction.


Voluntary muscles are ones that you consciously control to create movement. As you move, voluntary muscles contract and become tighter. They then relax when the movement is over. However, sometimes a muscle, or a few muscle fibres, contracts on its own, causing a muscle spasm or cramp.

Spasm vs. Cramp

The difference between a muscle spasm and a muscle cramp is the force of the contraction. If a muscle quickly contracts and releases without pain, it is a spasm. A prolonged and painful contraction is a cramp.


According to, the exact cause of muscle cramps isn't known, but they can occur if you don't stretch enough, the muscle is tired, or the muscle isn't getting enough oxygen. Other factors may include heat, dehydration, or not enough salt and minerals (electrolytes).


According to, the best prevention is stretching, drinking plenty of fluids, and not overexercising, especially in hot weather.


Sometimes muscle spasm or cramp may be a symptom of illness or side effect of medication. Consult your health care provider as appropriate.

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About the Author

Carol Wiley started writing as a technical writer/editor in 1990, was a licensed massage therapist for almost 12 years and has been writing Web content since 2003. She has a Bachelor of Science in aerospace engineering, a Master of Business Administration, a Certificate in Technical Writing and Editing and a Certificate in Massage Therapy.