A muscle spasm, also known as a cramp, twitch or charley horse, is the sudden, involuntary forced contraction of a muscle. Here are the main causes.

Muscle cramps are involuntary, sudden, and painful contractions of one or more muscles. Causes include dehydration, mineral loss, muscle overuse or injury during exercise, and pregnancy.

Medically reviewed by Smita Patel, DO Hypnic jerks, also known as sleep starts or hypnagogic jerks, are abrupt muscle contractions or twitches that happen as soon as you fall asleep. Up to 70% of ...

What causes muscle twitching? Our body's nervous system is constantly telling our muscles what to do without our having to consciously thinking about each action.

But the causes of leg cramps are wide-ranging. Need a break? Play the USA TODAY Daily Crossword Puzzle. Muscle cramping can be a sign that there are imbalances in your body’s levels of certain ...

Though many people experience muscle twitching, it's often incorrectly identified as a muscle spasm. While both are involuntary contractions of a muscle, muscle spasms and muscle twitching aren't ...

Clonus reflex is a set of rhythmic, involuntary muscle contractions. Learn about the causes, symptoms, and treatment options for this condition today.

Dystonia involves involuntary muscle contractions, but you're not out of options. Discover how botulinum toxin, DBS, and therapy can restore control.

Running coach Tom Craggs explains what causes delayed onset muscle soreness (DOMS), what to do once it kicks in and how to reduce your risk of getting it.

Dystonia is an involuntary muscle contraction that causes abnormal posture. People may experience twisted and repetitive movements that can affect any muscle in the body.

To understand what causes muscle fatigue, it’s worth looking at what exactly muscle fatigue is. If you exercise regularly, you may be familiar with the sensation of a dull ache in your muscles ...