Wrist Rotations with Straight Bar

How to

1. Hold a barbell with both hands and your palms facing down; hands spaced about shoulder width. This will be your starting position.
2. Alternating between each of your hands, perform the movement by extending the wrist as though you were rolling up a newspaper. Continue alternating back and forth until failure.
3. Reverse the motion by flexing the wrist, rolling the opposite direction. Continue the alternating motion until failure.

Instructions from free-exercise-db (public domain).