Instructions
Sit on a bench with back support.
Grip a dumbbell at one end using both hands. Your palms should be facing inward.
Hold the dumbbell overhead with your arms fully extended. This is the the start position.
Keep your upper arms close to your head (biceps roughly level with your temples) and near to 90degrees to the floor.
Moving only your forearms, lower the dumbbell in a smooth arc behind your head until your forearms and biceps touch. Hold for a count of one.
Return to the start position by using the triceps to extend your arm and raise the dumbbell. Exhale as you do this.
Repeat.