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 ...

Muscle spasms in hands are common for people with rheumatoid arthritis. Get tips for prevention and easing hand pain.

While sitting still at your desk or watching TV, you sense a feeling of muscular discomfort in your arm or leg. It’s not quite a charley horse, but you can see your skin pulsating involuntarily, as if ...

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 ...