Stabilize body in good alignment (abs tight, chest up, back straight) against tower with feet in comfortable position. Grip bar over head and position upper arms parallel to the floor. Slightly bend forward at hips. In a controlled motion, keeping upper arms parallel to the floor, extend bar down until arms are approximately straight. Contract triceps fully, without compromising form. While maintaining the controlled motion, return bar to starting position. Do not allow muscle to relax before next repetition.
Here are a few suggested alternative exercises:Ball Band French CurlBall Band Triceps KickBackBand KickBacksBand Overhead ExtensionBand Tricep ExtensionClose Grip Bench Press - BarbellClose Grip Dumbbell PressDecline Dumbbell Close GripDips - MachineDumbbell Lying ExtensionTricep Extension - Hammer Strength