Barbell seated overhead triceps extension

Sit on a bench with your back straight and feet flat on the ground. Hold a barbell with an overhand grip, hands shoulder-width apart, and raise it overhead. Lower the barbell behind your head by bending your elbows, keeping your upper arms close to your head. Pause for a moment, then extend your arms to raise the barbell back to the starting position. Repeat for the desired number of repetitions.