Sit on the triceps dip machine with your back against the pad.
If possible, position the levers of the machine as close to your body as possible.
Grasp the levers.
Keeping your torso upright and elbows close to your body, exhale as you push the levers down until your elbows are fully extended.
Hold for a count of two.
Inhale as you return the levers to the starting position.
Repeat for the prescribed number of repetitions.
Comments and tips
To effectively target your triceps brachii, keep your torso upright and elbows close to your body, as this will emphasize elbow extension. Leaning forward and using a wide grip will utilize horizontal shoulder flexion, which would place more emphasis on your lower pectoralis major.
Do not shrug your shoulders.
For the safety of your elbow joints, do not lock them out forcefully at the bottom of the movement, as this may add unnecessary stress to the joints.
The machine triceps dip is similar to the bench dip, which was found to be one of the most effective exercises for the triceps brachii by the American Council on Exercise (ACE).