Sit on an upright bench, back firmly against the bench’s back rest, and grab a straight-bar or an EZ-bar with your hands slightly narrower than shoulders width apart. The bar or EZ-bar should be above your head with your arms outstretched and your triceps squeezed.
Lower slowly your forearms beyond your head until your elbows are at a 90° angle. Then slowly come back to the starting position and squeeze your triceps at the top. Keep your back straight throughout the movement. Repeat for desired reps.