Adrenaline increases the "alertness" of the nervous system, meaning it's ready to trigger muscle contraction. It also increases the amount of blood flow and changes the tension of the muscles, which, ...

Infectious agents can cause muscle twitching and spasms, too. The most commonly known is probably tetanus, which causes a phenomenon called lockjaw, where the neck and jaw muscles contract to the ...

Doctors identify these movements as 'fasciculations', because they occur when individual nerve fibers, which control small muscle groups activate independently to produce brief muscle contractions.

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 ...

Chrissy Teigen took to Twitter this week to detail a health ailment. The model on Tuesday shared a video of her arm uncontrollably twitching. “Hello my arm won’t stop doing this after I stretched ...

A muscle spasm — also known as a charley horse, muscle cramp or twitch — is a sudden, involuntary movement in one or more muscles. Common causes include stress, exercise, or dehydration, but nerve ...

After a grueling CrossFit workout on a hot Summer morning that involved kettlebell swings, goblet squats, and about 100 walking lunges, my lower body was toast. But what was weird was that my left ...

slow-twitch muscle fibers, which move more slowly but help to keep you moving longer fast-twitch muscle fibers, which help you move faster, but for shorter periods “Twitch” refers to the contraction, ...

NEW YORK (CBSNewYork) - When you hear the word "Botox," you probably think of a cosmetic procedure to reduce wrinkles. You may be surprised to know that Botox has some very serious medical uses, too.