Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.

Muscle cramps are usually blamed on dehydration or low potassium. It’s simple. It’s familiar. And it’s incomplete. The real cause has more to do with how your nervous system controls muscle ...

The flow of water within a muscle fiber may dictate how quickly muscle can contract, according to a new study. The flow of water within a muscle fiber may dictate how quickly muscle can contract, ...

Proprioceptive neuromuscular facilitation (PNF) is a form of assisted stretching. It combines passive stretching with muscle contraction. First, your partner applies force to stretch your muscle ...

At one point or another, we’ve all experienced the unexpected, intense pain of a muscle cramp. Muscle cramps, also known as muscle spasms or charley horses, are the involuntary contraction of muscle ...

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 ...

You're relaxing on the sofa when suddenly your eyelid starts twitching. Or perhaps it's a muscle in your arm, your leg, or ...