Grab hold of a suitable weight barbell or EZ bar and take a seated position at the end of a flat bench. Take an overhand, shoulder-width grip on the bar then slowly lower your torso back until it is flat on the bench. Keep your core tight and your feet flat on the floor, press the bar directly up so that your arms are fully extended and the palms now face up and forward. This is the starting position.
Commence the movement by bending at the elbows to lower the bar toward your forehead. The elbow acts as a hinge joint - the upper arms should remain stationary and the movement comes only from the forearms. You should feel a large stretch through the triceps. Inhale through the movement.
When the elbows have reach their maximum range of motion and before the bar hits your forehead, reverse the movement by pushing up through the triceps and extending the arms back to the starting position, exhaling as you do.