1. Sit on a bench or sturdy chair and ensure that your back is in contact with the back of the bench/chair
2. Take a firm grip of a dumbbell *Warning*, only perform this exercise if using a fixed or secure, screw-seal dumbbell. If using a dumbbell that is not extremely secure, perform tricep kickbacks instead
3. Hold the dumbbell directly overhead with your arm fully extended, your biceps should be roughly in line with your ears
4. Bend at the elbow ensuring that your upper arm remains fixed in place, and lower the dumbbell behind your head until your arm is bent at a 90-degree angle
5. Using only your triceps, extend your arm driving the dumbbell back up to the overhead starting position
The primary muscles used in Seated Single Overhead Tricep Extensions are the Triceps.