What Is the Trapezius Muscle? Trapezius muscles are large, paired, triangular muscles in the back of your neck and upper back. They extend down your back, but they’re mostly involved in the movements ...

Experts share the best trap exercises to look cut, prevent injuries in and out of the gym, and improve your posture.

Ask someone in the gym to point to their trapezius muscles, and they’ll probably gesture toward the small mounds nestled between their neck and shoulders—but that’s really just the tip of the iceberg.