Let’s get one thing straight: Muscle is muscle. Despite what many fitness influencers may have you believe, there’s no such thing as "lean muscle" or "bulk muscle." It’s all made from the same stuff.

Skeletal muscle is the type of muscle that controls movement. Problems with these muscles can be minor, life-threatening, or ongoing problems that make it hard to perform basic daily activities.

The muscular system works to control the movement of our body and internal organs. Muscle tissue contains something called muscle fibers. Muscle fibers consist of a single muscle cell. They help to ...

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 ...