Section: Human Body

Facial Muscles: How You Smile, Frown, and Express Emotion

Smooth Muscles: The Movers You Never Control

How Your Heart Is the Hardest-Working Muscle

Why Posture Depends on Tiny Muscles You Can’t See

The Hidden Power of Core Muscles

Fast-Twitch vs. Slow-Twitch Muscles: The Speed Secret

What Causes Soreness After a Workout?

How Muscles Grow Stronger After Exercise

Why You Get Muscle Cramps — and How to Stop Them

The Science of Flexing: What Really Happens When You Move

How Muscles and Bones Work Together

Skeletal, Smooth, and Cardiac: Meet Your Muscle Trio