Set the Smith machine bar to the height of your shoulders when you are seated on the bench.
Set the safety pins to prevent the bar from dropping past your shoulders.
Sit on the bench with the bar behind your shoulders.
Grasp the bar with a wide overhand grip and unlatch it by rotating your wrists backward.
Exhale as you extend your elbows to press the bar upward, keeping your forearms perpendicular to the ground.
Inhale as you lower the bar behind your neck, stopping when you reach shoulder height.
Repeat for the prescribed number of repetitions.
Rotate the bar forward to latch it back on to the rail.
Comments and tips
Throughout the exercise, maintain an upright torso, with your chest out, and gaze forward.
The seated Smith machine behind-the-neck shoulder press is not recommended, especially if you are a beginner. The reason is that, bringing the weight behind your neck under heavy load may place your shoulder joint in a position where it can get damaged or dislocated. Your ligaments and muscles, which keep your shoulder joint stable, can either be traumatically overcome by the weight you are lifting or can be damaged over time due to repetitive stress brought about by the exercise.
It is possible to perform the seated Smith machine behind-the-neck shoulder press safely. Some people have more range of motion in their shoulder joint than others do or have stronger ligaments and muscles than others do. However, the risk of injury is not worth it. A typical barbell shoulder press can be performed as an alternative.