Barbell lying back of the head tricep extension

Lie flat on a bench with your feet flat on the ground and your head at the end of the bench. Hold a barbell with an overhand grip, hands shoulder-width apart, and extend your arms straight up over your chest. Keeping your upper arms stationary, slowly lower the barbell behind your head by bending your elbows. Pause for a moment, then extend your arms back up to the starting position. Repeat for the desired number of repetitions.