Place hands on knobs at each end of roller.
With left hand gripping knob, relax grip of right hand and slide grip downward so fingers are under bottom of knob (by ulnar deviation) and regrip. Relax grip of left hand and rotate knob with right hand so thumb travels closer to body (by radial deviation). Repeat sequence with opposite hands, alternating back and forth until weight plate has raised up near hands. Lower weight steadily with opposite movement or loosen grip slightly to control descent of weight stack.
Exercise is performed on specialized piece of equipment which includes knobs at each end of wrist roller.