Starting Position: Holding two dumbbells, kneel and rest your elbows on a bench with approximately a 90 degree bend at the elbows and the dumbbells hanging freely off the edge of the pad. Pronate your forearms (rotate forearms to face palms downward and the bottom of the forearms are resting on the bench) while keeping your wrists in a neutral position (not in flexion or extension).
Downward Phase: Inhale and slowly allow the wrists to move into flexion (allow dumbbells to move towards the floor) without releasing your grip, extending your arms or leaning forward / backward. Hold this end position briefly.
Upward Phase: Exhale and slowly contract your forearm extensor muscles (along the top of the forearm) and roll your wrists to pull the weight up and return the dumbbells back to the starting position.