Set up a cable machine by placing the pulley higher than your head level, with a short bar handle attached
Stand close to the machine and grab the handle with and overhand grip, palms facing down
Keep the chest up and elbows pressed against your body
Keep the shoulder blades pushed behind and pull the handle down extending the elbow
Pause at the bottom and finish the rep, squeezing the triceps
Breathe in at the bottom and repeat the movement