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 one side of a dumbbell (do so by allowing your palms to hold the underside of a dumbbell plate). *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 overhead with your arms fully extended, your biceps should be roughly in line with your ears
4. Bend at the elbow ensuring that your upper arms remain fixed in place, and lower the dumbbell behind your head until your arms are bent at a 90-degree angle
5. Using only your triceps, extend your arms driving the dumbbell back up to the overhead starting position
The primary muscles used in Seated Overhead Tricep Extensions are the Triceps.