Grab hold of a suitable weight barbell and position yourself for the lift. Take either a seated position at the middle of a flat bench (facing lengthways) or a kneeling position adjacent to a flat bench (facing crossways).
Take an overhand, palms down narrow grip on the bar and position your arms so that your forearms are predominantly on the bench whilst your wrists are hanging off it in a relaxed (non-flexed) manner. This is the starting position.
Commence the movement curling the wrists up as high as they will go and exhaling. The forearms remain stationary and the movement comes only from the wrists.
When the wrists have reach their maximum range of motion, inhale and reverse the movement back to the starting position.