WHAT'S UP WITH ...MUSCLE FLUTTERS

Experts explain why you sometimes get little twitches under your skin.

- KAYLA BLANTON

YOU'RE SITTING PERFECTLY still, yet you can see the skin on your leg, hand, eyelid, or rib cage pulsing, as if a bug is bouncing on a tiny trampoline underneath. Technically called fasciculations, the twitches are spontaneous, rapid contractions of a few muscle fibersthey're common and usually harmless, says Christopher Fry, Ph.D., an associate professor of athletic training and clinical nutrition at the University of Kentucky and codirector of the school's Center for Muscle Biology. Unlike muscle spasms or cramps, they aren't painful, but they can be incredibly annoying and just plain weird.

WHAT CAUSES THE TWITCH?