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.

Add Yahoo as a preferred source to see more of our stories on Google. Tweaked by a muscle twitch? From an uncontrollable fluttering eyelid to a pulsing calf muscle, these small, rapid involuntary ...

You're relaxing on the sofa when suddenly your eyelid starts twitching. Or perhaps it's a muscle in your arm, your leg, or your foot that begins to spasm—sometimes for a few seconds, sometimes for ...

Fast-twitch fibers help with explosive movements like sprinting and weight lifting. Genetics and training influence the distribution of fast-twitch and slow-twitch muscle fibers. Doing strength ...

You’re relaxing on the sofa when suddenly your eyelid starts twitching. Or perhaps it’s a muscle in your arm, your leg, or your foot that begins to spasm – sometimes for a few seconds, sometimes for ...