One-Arm Tricep Extension Steps:
Step 1: Sit on a military press bench while holding a dumbbell in one hand. The dumbbell should either be positioned on your thigh or stood up straight.
Step 2: Lift the dumbbell up so that it is at shoulder height and then extend your arm up over your head. Your entire arm should be perpendicular to the floor. The dumbbell should be over your head. Your other hand can be extended out the side, held by your waist or can support the arm that has the dumbbell. You can also hold onto a fixed surface if you wish.
Step 3: Turn your wrist until the palm of your hand is facing forward and your pinkie is facing the ceiling. This is the starting position.
Step 4: Bring the dumbbell behind your head slowly as you hold your upper arms stationary. Inhale as you do so, and stop for a second when your triceps are fully extended.
Step 5: Flex your triceps and return to the starting position. You should exhale as you do so.