Add Yahoo as a preferred source to see more of our stories on Google. Many of us have felt a muscle in some part of our body suddenly and involuntarily tighten, causing a twitch or even severe cramp.

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 ...

Magnetism can refer to the alteration of gravitational pull to the North Pole as well as to the invisible attraction two people feel toward one another. Both definitions, however, indicate a hidden ...