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, ...

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 ...

Add Yahoo as a preferred source to see more of our stories on Google. 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 ...

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, ...

The arm extends from the shoulder to the wrist, including the upper arm and forearm. Different muscles may work together in intricate ways to help the arm, wrists, fingers, and hands function. Knowing ...

Twitching at night—it’s something few of us talk about, yet it’s also a phenomenon that impacts Americans when it comes to sleep quality. And even if you feel like you’re getting enough sleep, you ...